Questions on: Tomatoes

Ron Smith, Horticulturist, NDSU Extension Service


Q: My grandma has had a problem with her tomatoes getting black spots and rotting a day after they are picked. Most of the tomatoes can't be eaten. She said she is rotating the plants. She also grows pepper plants. They are always good. She doesn't water with a hose or sprinkler. She uses a bucket and waters with a pan, so there is no splashing. (Springfield, Ohio)

A: It sounds like your grandma is using seed she saved from the previous year. If so, she should purchase fresh seed each year because many diseases can be carried over in the seed of infected tomatoes. If that isn't the case, then tell her to get hybrid tomatoes with the letters VFHNT after their names. These are tomatoes bred for resistance to the most common bacterial, fungal and virus diseases.


Q: I had someone in the office with a garden supply catalog that sold red-colored tomato accessories, such as red wall-o-waters, red root zone waterers and red mulch. Is there any research about the successful use of these red products or is it advertising hype? (Ward County, N.D.)

A: Research years ago using red plastic mulch under tomato plants reported an increase in production. We tried to duplicate that at the Dickinson Research Extension Center, but did not find that to be true. There is probably a nugget or two of truth, but I would say the hype outweighs the truth somewhat. The successful research used red plastic mulch and drip irrigation, but nothing else.


Q: I want to start a greenhouse business growing hothouse tomatoes for local supermarkets. I am a smoker and have heard that greenhouse tomato plants will be subject to more disease problems because I smoke. I have grown tomatoes in my outdoor garden with no apparent problems. Why would the situation change if I were growing them in a greenhouse environment? (e-mail reference)

A: The big answer is that it is in a greenhouse environment. In attempting to control the factors of growth, such as heat, light and nutrients, we also are creating an artificial environment that removes some of the checks and balances that Mother Nature throws into the mix. The big problem with smoking (as far as tomato plants are concerned) is that many tobacco leaves are carriers of tobacco mosaic and spotted wilt virus. Both diseases can be very destructive to a greenhouse tomato crop. The chance of you giving up smoking is probably remote, so if you persist in this habit and in your desire to grow greenhouse tomatoes, be sure to follow the best sanitation procedures possible. Wear a lab coat to cover your clothing and thoroughly wash your hands before going into the greenhouse to handle the plants.


Q: I have thousands of tiny, white gnats flying around my tomatoes and other plants when I water. I used a Black Flag bomb, but it didn’t work. It doesn't appear that they are bothering anything, but I have noticed that my tomatoes are not setting fruit. What should I do? Thanks for all the info you have been sending everyone’s way. (Valley City, N.D.)

A: This is a white fly infestation, which is somewhat unusual for outdoor tomatoes. They are a curse in greenhouse plantings because they can reduce quantity and quality. Generally, white flies are controlled by predator wasps in commercial operations. For homeowners, the best bet is to get yellow, sticky cards and place them around the plants that are infested. Replace the cards once they become full of this pest. You also can follow an aggressive pattern of spraying with insecticides, such as Sevin, when you see them flying. The egg masses and immature nymphs will not be affected by the spray for the most part. As Calvin Coolidge once said, "persistence and determination alone are omnipotent."


Q: My wife purchased a self-watering container system from a catalog house last spring. We planted three tomato plants in the container, but found out it was one too many. The plants shot up and had lots of fruit, but when the fruit started to ripen, the bottoms turned black. Some of the fruit have small, black insect casings attached. At least I think they are insect casings. The inside of the fruit is contaminated beyond the black exterior. Also, the leaves started to turn yellow after 30 to 45 days. Any ideas? (e-mail reference)

A: My faith doesn't extend to automatic or self-watering containers. To grow good fruit requires human judgment, which these take away. Secondly, what you saw getting started probably was blossom end rot. This is caused by a cell breakdown on the blossom end of the fruit (imagine that!) from insufficient calcium being transported to the forming cell tissue at that point. The cells collapse and the secondary organisms that cause the rot you see make an appearance. Generally, it is confined to certain cultivars of tomatoes, the first fruit set or plants that are under accelerated growth. The yellow leaves could be caused by too much water in a poorly-drained container, gray leaf spot or early blight. These are pathogens brought on by heavy dews and frequent rains where the foliage has not been allowed to dry sufficiently. Both can be controlled with fungicides, but at this time of the season, I don't recommend it.


Q: Is it a good idea to fertilize tomatoes as they set fruit or will it result in more foliage? The plants are huge and look healthy. Also, my neighbor has a plum tree that is sending up many shoots in my yard. If I spray them, will it damage her tree? If not, what should I use? They are a real nuisance! Thanks for your advice. I enjoy your column and find it helpful. (Fargo, N.D.)

A: Regular fertilization with a balanced fertilizer, such as Miracle-Gro, will improve growth and fruit set. As long as they are not showing any signs of deficiency and are setting fruit to your satisfaction, don't worry or fertilize. As for the plum suckers, cut them back and then spray with Sucker Stopper RTU. This will stop the suckering. I took my plum trees down years ago because of the continual suckering problem. Thanks for the nice comments about the column!


Q: Many of the leaves on my tomato plants began to yellow and the green tomatoes that were emerging began splitting on the bottom. The tomatoes were smaller than golf balls when this began happening. It appears that new fruit also is affected. We recently had heavy rains, so I am wondering if that might have something to do with it. (e-mail reference)

A: No doubt about it. Tomatoes need a rather consistent supply of water in order to produce well and not split. When it doesn't rain, the gardener must accept the responsibility of providing adequate water for normal growth.


Q: We have a terrible problem with blossom end rot, but only on our zucchini. The tomatoes and cucumbers are fine. Any ideas? (e-mail reference)

A: Harvest the zucchini, cut off the degraded end and consume the rest. Avoid vigorous cultivation and wide swings in irrigation cycles. As with some tomato cultivars, blossom end rot usually is limited to the first fruit set. Later fruits are usually free of the disease.


Q: This is my second attempt at planting tomatoes in my yard. I have been able to produce nice plants and fruit, but the skin is so tough that you can hardly eat it. What the heck can I do to avoid this situation? (e-mail reference)

A: Plant a different species of tomatoes. If that doesn't work, I don't know what else to tell you.


Q: I was wondering if watering my tomatoes at night is OK. I also noticed that the following day my tomatoes start wilting again. Why? (e-mail reference)

A: Watering during the early morning hours is better. That way the plant can efficiently use the water with the warming sun and the chance for disease development is greatly reduced. The wilting during the day is a normal reaction as long as the soil is moist. The plants are probably getting full sun and/or reflected light off a light-colored surface. As long as the plants recover, you have nothing to worry about. The wilting will disappear as the plants mature.


Q: Is there anything I can do if my tomatoes have too much nitrogen? I have blossom drop. (e-mail reference)

A: Nitrogen is leachable, so double water a few times to see if that helps. Flower drop also is caused by extremes in watering regimes, temperature swings or root damage.


Q: I'm a novice gardener and recently came across your Web site. I started tomatoes from seed and on the package it said to transplant the seedlings once they had two pairs of leaves. I planted all of the seeds in one big pot because I didn't anticipate that all of them would come up! I waited until they had two pairs of leaves, which I assumed were the first leaves and then the true leaves. The first leaves have started yellowing and I'm worried that I might have killed my plants. Should I have waited longer? Any advice you might have on growing tomatoes from seed would be much appreciated. (e-mail reference)

A: Those first two leaves are called seed leaves or cotyledons. It is normal for the cotyledons to gradually die after the true leaves open up. Wait about two more weeks before planting outside, unless you live much farther south than North Dakota. Watch out for late-spring frosts because tomatoes are not tolerant of frost. If a frost is predicted, then cover the plants with an old sheet or newspaper for protection.


Q: I bought a house two years ago. The previous owner had cherry tomatoes. After I planted my vegetables, I also got more cherry tomatoes. Is there a way to keep the killer cherry tomatoes from returning this year? (e-mail reference)

A: Presprout them by solarizing the soil with clear plastic before planting your garden. Once sprouted, they are easily cultivated out. There should be diminishing plant populations over the years anyway if you are not planting any more cherry tomatoes. The solarization should take care of any seed left in the soil and you can grow your veggies free of invading cherry tomatoes!


Q: My father-in-law is an incredible gardener. Year after year he grows beautiful, tasty, juicy tomatoes. He keeps seeds from the year before to plant the next year. This year his crop of tomatoes looked amazing. The plants were healthy, they flowered, tomatoes appeared and grew to amazing sizes, but they did not fully ripen. Most of the tomatoes stayed green. He didn't do anything differently from other years. We have looked high and low on the Internet for an answer, but could not find one. (e-mail reference)

A: The main problem is the fact that your father-in-law saves the seed each year. Not that this is a bad thing, but tomatoes are bred for certain climate conditions. When the genetic information is erased or lost, as it would be in saving the seed from year to year, that characteristic of ripening within a certain time period and day length is lost. For example, the tomato hybrids that grow and produce well in a greenhouse in Florida or south Texas will not do well in our northern gardens and vice versa. Another factor that influences the ripening of tomatoes is the heat units. If Toronto were short on heat units, the tomatoes would be slower to ripen. We had that problem in North Dakota last year when our summer was cool through August, so very few tomatoes had ripened to that point. I was telling everybody to dig out their grandmother's green tomato recipes, but September turned warm and we had an extended growing season through October. The extended season allowed the tomatoes to ripen before the killing frosts killed the plants. Tell your father-in-law not to give up, but try some hybrids next year.


Q: I have tomato plants that are 5 feet tall. Can I snip the ends off the branches to encourage fruit growth such as you do with squash? I do pinch off the suckers between the crooks of the branches. Thanks for any help you can give me. (Bismarck, N.D.)

A: Pruning the plant will keep it compact. Many people do get rid of the sucker growth that appears on the main stem. To get larger, fewer fruit, remove any blooms that appear before fruit set can take place. If you have overfertilized the tomatoes, the growth will be mostly vegetative. In that case, any pruning would be of little help.


Q: I have a problem with my tomatoes. The tomatoes get small, dark brown spots on the leaves. After that, the leaves turn yellow and the brown spots grow together. I’m worried I’m going to lose my tomatoes because it seems to spread fast. What do I need to do? (e-mail reference)

A: You have blight, but I can’t tell which one. Here is a laundry list of what you can do to prevent it from spreading. Pick off all infected leaves. Don’t water overhead because the splash is an excellent conveyor of the disease spores. Don’t overfertilize. Dig out the badly infected plants, but don’t hoe, weed or otherwise work the garden when dew is present on the foliage. If you believe there is a need, get the appropriate garden fungicide for vegetable crops and apply according to directions. Typical fungicides include mancozeb, benomyl and chlorothalonil.


Q: I used regular cedar mulch to place around my tomato plants to prevent rain splash. I had thought at one time that might not be good because too much nitrogen might be sucked from the soil, but the person at the outlet store said that it would take longer than a season. (e-mail reference)

A: Unfortunately, the person at the outlet store is wrong. The mulch can tie up nitrogen in a matter of weeks and would soon be evident symptomatically on the plants growing within. This easily can be offset by adding nitrogen to compensate for the tie-up in the soil microbes.


Q: I have someone with bottom-rot on their tomatoes. Any idea of the cause? (e-mail reference)

A: Blossom-end rot is a physiological disorder caused by an incomplete cell formation at the time of fruit development on the blossom end. It is common on early-setting tomato cultivars. It usually disappears when fruit develops. The way to avoid a recurrence is to maintain an even soil moisture level as much as possible and avoid dry/wet cycles. Don’t cultivate too aggressively around the plants and damage the roots, and avoid overfertilization with high-nitrogen material. The cell tissue breaks down due to insufficient calcium and other minerals that go into cell-wall development, so rotting pathogens then set in. The affected part can be cut out and the rest of the tomato eaten, but the tomatoes would have to be discarded if they are intended for market purposes.


Q: Can you please tell me if there are certain varieties of tomatoes that have a low acidic content? I’m trying to avoid getting canker sores. At the end of last summer, my husband and I got canker sores for the first time in our lives. After eating all of our tomatoes, we quit getting the sores. This year we only want to plant varieties that won’t cause these painful sores. (e-mail reference)

A: NDSU has done some studies on the acidity of tomatoes. The pH does vary, but mostly stays above 4.3. Some of the varieties that tested high for us (above pH 5.0) are health kick (5.04),vita gold (5.09), La Roma (5.08), Russian (5.09), super marzano (5.20) and classica (5.05).

People often mistake the pink- or yellow-colored varieties as having a higher pH (lower acidity), but that has not proven to be the case when looking at the research. Generally, the lower acidity taste is due to a higher proportion of sugar to acid in the fruit, so it is not as noticeable when eating. I would suggest allowing the tomato to remain on the vine until it has reached the maximum level of ripeness to allow for greater sugar accumulation and lower acid taste.

It is often thought that canker sores come from something like eating too many tomatoes, but it is often a sign of some nutritional imbalance in the body. I would suggest checking with a nutritionist, dentist or doctor to be sure that there is no mineral or vitamin deficiency (especially B12) in your system.


Q: I am growing tomato plants in my portable greenhouse. The plants are growing great and have flowers, but don’t produce many tomatoes. Is there a trick to getting the plants to fruit? (e-mail reference)

A: The trick is to get bees involved or shake the plants while they are in flower. It will make a big difference!


Q: I have started several tomato plants and herbs indoors in preparation for planting outside later this spring. The plants grow very fast, but the stems are spindle-thin and don’t seem to thicken up. What is wrong? (e-mail reference)

A: You very likely made the same mistake most people make in starting seed indoors, insufficient light. They need light and lots of it! This can be accomplished by the use of fluorescent bulbs. Use a warm white and a cool white bulb placed inches above the seeds and developing seedlings. Keep the lights on for 12 to 13 hours a day. Using this technique, you will get thicker, healthier plants. Also, don’t keep them too warm. Temperatures in the low 70s or upper 60s work best.


Q: I’ve had problems with blight in my tomato plants the last few years. I moved my garden to a different location, but the problem was worse. Are there blight-resistant plants or is there some treatment to control the blight? My plants are almost dead by the time the fruit starts to ripen.
(Fargo, N.D.)

A: Go through the garden catalogs and look for variety names with the initials VFNT and A behind them. This means that the variety is resistant or at least tolerant to the most common tomato problems, such as verticillium wilt (V), fusarium wilt (F), nematodes (N), tobacco mosaic virus (T) and alternaria (A). Avoid water splash when watering, working the soil around the plants when the foliage still has morning dew present and overfertilizing. Be sure the plants are located where they get full sunlight and good air circulation.


Q: I have a tomato plant that is now my second houseplant to be attacked by a strange problem! Little black, egglike gritty things are appearing on the underside of the leaves. The leaves are turning yellow and dying. (e-mail reference)

A: You can control these insects with Insecticidal Soap, which is a direct toxin to soft-bodied insects. It kills the insects by dehydrating them. Be sure to cover both leaf surfaces. This material is safe to use on edible plants and in the home on houseplants.


Q: My tomatoes were hit with fusilaria wilt this past summer. Is there an effective method of sterilizing the soil? Would a propane weed torch work? I would appreciate any help you could give me with this problem. (Detroit Lakes, Minn.)

A: If you use a propane weed torch, all you will do is warm the surface of the soil a little and perhaps kill a few languishing weed seeds, but nothing more. The best approach, when you have disease problems, is to get a resistant variety and plant in a different location in full sun. Always try to avoid water splash.


Q: I planted a tomato plant (can’t recall the name, but it grew small, cherry like tomatoes). It grew a lot of tomatoes, but almost all of them fell off while still green. Any ideas what caused the problem? (e-mail reference)

A: Usually fruit drop is caused by fluctuations in water availability or temperature swings. It could be the plant was not nourished sufficiently to support the fruit load.


Q: Over the past few years the lower leaves of my tomato plants have turned yellow and fell off. Eventually there was hardly any foliage and the plant produced very few tomatoes. I tried adding powdered milk to each plant when I put them in the ground. I thought this was working because they all looked good and then I noticed that the yellowing returned. (e-mail reference)

A: Hearing about using powdered milk on tomato plants is a first for me. Use Miracle-Gro or something similar at planting time for tomato and other vegetable plants. Avoid overhead watering; rotate the planting site, make sure the soil is well drained and that the plants get full sunlight. Also, try to select resistant cultivars.


Q: I have a patio tomato plant. This past week the bottom half turned yellow. It is in a pot with plenty of drainage, so I give it a pitcher of water daily. I do not know what to do. (e-mail reference)

A: It appears your tomato plant is showing the symptoms of early blight. At this stage, there is little that you can do about it. Carefully remove the affected foliage and avoid splashing water on the foliage when you water. If the plant doesn’t need water on a particular day due to cool temps, cloud cover or rain, then do not water. You should still be able to harvest some tomatoes.


Q: I purchased a tomato on the vine (a clump of two to five tomatoes still attached to the vine) at the grocery store. I left them on the kitchen counter, not in the refrigerator. They lasted for about two weeks. I ate all of them except one. When I cut it open to use it, the seeds were sprouting green leaves. I have never heard of this before. Usually tomatoes rot before I can use them. What caused the seeds to sprout inside a ripe tomato? (e-mail reference)

A: The chemistry in the fruit changes as it continues to ripen. It got to a pH level where the seed was able to germinate.


Q: I thought my wife had a senior moment when she started saving gallon plastic milk jugs. When she had about 20 to 25 jugs, my curiosity got the best of me so I asked her what in the world she was going to do with them. She promptly told me that she was going to cut the bottom off the jugs and create miniature hot houses for our tomatoes and peppers. She went on, treating me somewhat like a small child, to say she could get a month head start on all the neighbors by putting the jugs over the plants. She continued to explain that with the jugs in place, she did not have to worry about the sun baking the tender plants. I went to my shop and sharpened the lawnmower blade, amazed by her knowledge. (e-mail reference)

A: As usual, your wife was right on! You have lived a sheltered life because this practice dates back to the invention of plastic milk containers. Get out of your garage more often and listen to your wife. I do and am still learning from her!


Q: I had someone call in wondering about her tomato and potato plants. She described the plants as having thick leaves that curl upward. I suggested it may be pesticide damage. She had the same problem last year. The plants did get better, but it was so late in the season they didn’t produce any fruit. She also said that about 10 plants out of 100 appear healthy, but the others all exhibit the same symptoms I described. I asked if the healthy plants were all in one area, and she said that they are scattered all over. (Carson, N.D.)

A: Your analysis sounds about right - but it could also be any number of problems, or simply a characteristic of the cultivar. It could also be that this particular person is saving their seed every year and is carrying some disease over on the seed. That is the extent of my guesses - beyond that, samples should be sent into the diagnostic lab.


Q: I bought a yellow tomato plant that was growing nicely until I transplanted it into a pot using garden soil. I believe the soil has Miracle-Gro and fertilizer in it. The plant is not dying, but it has now turned black and won't grow. (Eureka, S.D.)

A: Obviously the plant doesn't like where you placed it. If the pot doesn't freely drain, that could be the problem. If the plant is black and not green, then it is dead. I don't know what else I can say with the information you've given me. Miracle-Gro potting soil is a quality product and has been on the market for a long time. You might do a seed test using corn and beans to see if they grow. If they do, then the problem isn't the soil.


Q: Someone called me about young tomato plants that they purchased about a week ago. They were doing very well, but they have white spots on the leaves and they are curling. They still have the plants in the house. Do you have any idea what could be wrong? (Carson, N.D.)

A: Yes, the fact they are not yet planted in the garden! Tell them to get them in the ground ASAP. Tomato plants sitting in the house at this time of year are not going to look good. They should recover when transplanted if they haven't been kept in too dark a location.


Q: What would cause a green and young tomato about the size of your little finger to split on the bottom? (e-mail reference)

A: A sudden surge of moisture after an extended period without.


Q: I've got three varieties of tomato growing in my garden: Earl girl, better boy and brandywine. My brandywine plants have leaves that are yellowing and necrotic from tip to stem. Is this variety more susceptible to disease? Do they have some mineral requirement that the others don't? (e-mail reference)

A: Brandywines do not have special requirements. If the problem is isolated to a few leaves and stems, carefully cut those off and dispose of them. If the malady continues to progress, then get rid of them and replant.


Q: Are zucchini, green bean or tomato leaves toxic to cattle? (Cando, N.D.)

A: Tomatoes are definitely toxic to livestock. The only green bean species that is toxic to livestock that I have listed is Phaseolus lunatus. With squash, it depends on the nitrate levels found in the foliage.


Q: This year our tomato plants are drying up starting from the bottom around the center and then moving up. They are getting plenty of water and we even gave them Miracle-Gro. The plants aren't very big. They do have tomatoes and some are nice sized. Any idea what could be drying them up or what we can do? (Selby, S.D.)

A: It is tomato blight time again in the Upper Midwest! Our wonderfully variable regional weather has set the stage for tomato blight diseases. There are four diseases that fall into this general category, each with distinct symptoms and caused by different fungi. Based on your description, I would guess that yours is early blight. It attacks the older foliage and slowly works its way up the vine. Secondary damage to the fruit is manifested by sunscald from foliage loss.

Avoid overhead watering or using mulch. Use only clean seed and don’t plant in the same location each year. Spraying with fungicides at this time will do little good and only contaminate the environment with unnecessary pesticide. Be sure to clean the garden of all litter this fall and turn the soil over before the snow flies if you have a chance.


Q: I had a gardener ask me why the blossoms would suddenly fall off his tomato plants. Can you explain that one? Also, why would cucumbers suddenly quit blooming? (Mandan, N.D.)

A: One answer to both questions, high temperatures and a lack of adequate moisture. While both like warm temperatures, the hot weather we've been having and the lack of consistent rainfall will cause both blossom abortion and non blooming. Even our zucchini plants are way down on production this year and that's saying something!


Q:  We've been so pleased to have ripe tomatoes so early in the season but they have suddenly started to get hard and yellow at the stem ends. We are raising them in an earth box. The three varieties we have are cherry tomato, early girl and beefy boy.  Do you have any idea what is happening?  (Bismarck, N.D.)

A:  Just when I think I have heard about every problem dealing with tomatoes, someone comes up with a new one! I suspect something is wrong with the environment if it is hitting all the varieties equally.


Q: I had a lady call regarding her tomatoes. The plants she has seem to be growing quite tall but not bushing out. She is wondering if it’s okay to pinch them back to promote lower growth? Also, what do you think of the blossom spray products? I have a flower bed in town that a lady has had trouble with the last two years. The geraniums and petunias have severe yellowing. Could iron deficiency be a possibility? She also would like to know a source for buying a powdered iron supplement. (Hettinger, N.D.)

A: Yes, she can go ahead and pinch back the tomatoes without any effect. She may be using too much nitrogen fertilizer. Blossom spray products are fine but usually aren’t necessary. The yellowing of the geraniums and petunias could be an excessive salt accumulation and/or too high a pH. Iron sulfate may solve the problem. Chelated iron would be better if it can be found. Most garden stores have some kind of iron fertilizer product.


Q: I’ve got a veggie question for you. I know a man who has greenhouse tomatoes that are 8-10 inches tall. I don’t know the variety. The top leaves are curling but not discolored. He uses rain water and says the bottom leaves look vibrant and healthy. Any ideas? ( Bowman, N.D.)

A: It’s nothing to worry about -- just something that happens with many cultivars of tomatoes as they grow. It is believed that this is a reaction to high temperatures, sort of a built-in plant water conservation technique used by the most tender and vulnerable leaves.


Q: We're growing some tomato and pepper transplants. Some of the tomatoes are showing strong purpling of the leaves with the veins remaining green. They are growing in small 1 1/4 inch size plug trays. Their about 6-7 inches tall. Would adding some Miracle-Gro help? Should we transplant them into something larger? How about the temperature? The temperature they are being kept at is around 60 degrees. (Cando, N.D.)

A: The temperature is too low, there is not enough soil mass, and they are suffering from lack of nutrients. Raise the temperature to about 70-72 F., repot into larger containers or packs and fertilize every two weeks with a complete fertilizer.


Q: My friend and I are having a debate over whether a tomato is a fruit or a vegetable. Can you please answer this question for me? (E-mail reference)

A: Tomatoes are fruits eaten as vegetables. Here's another one for debate: rhubarb is a vegetable eaten as a fruit.


Q: I have a bad problem with tomato blossom rot. I have been told it’s caused by a calcium deficiency. I have tried a foliage spray with mixed results. Is there some other way to address this problem? Also, my annual flower bed dirt has become so gumbo like that the plants will no longer root. I live in Crosby and the water comes from the city’s lime softening plant. I think this is part of the problem. I am going to replace the dirt and start over but I have to use the same type of dirt for replacement. What can I mix in with the native dirt to prevent this problem from recurring? (Crosby, Minn.)

A: Blossom end rot is a cultivar/environment interaction. Generally the cause is from overzealous cultivation that damages the roots and results in a reduced nutrient uptake. It could also be from a wide fluctuation of watering or rainfall. Finally, some cultivars in some climates are prone to this malady, at least with the initial fruit set, thought to be tied with cold soil or cold water in the root zone. But, since you told me that the water source is already softened, and most likely with sodium, the problem is that particular cation is in such high concentration that it is destroying the structure of the soil and negatively affecting the growth of your plants. You need to get another water source or treat the water with a RO unit to remove the salt. It will simply cause the problem again later on even with all the soil being replaced. Canadian sphagnum peat moss is an excellent soil conditioner, and I would suggest incorporating generous amounts into the soil to improve the tilth.


Q: What causes my tomatoes to be mealy? They look great, are firm and ripe, but when we cut them open they are mushy and mealy. What can we do to avoid this? (E-mail reference)

A: Change to another cultivar if you are growing them in your garden. If you are purchasing them from a supermarket, complain to the produce manager. I don’t know specifically what causes the problem but I would guess it has something to do with environmental/cultivar interactions. If the tomatoes you are growing are from seed you have saved from previous crops, that could be the answer. If I come across a definitive answer either via my references or another authority, I'll post it to my Web site.


Q: If I use Miracle-Gro on my tomato plants, will it go into the tomatoes? My children will not eat them if I use it. Also, a lot of my tomatoes have big cracks in them. What is causing the cracks? (Jamestown, N.D.)

A: Miracle-Gro is a fertilizer compound of some 13 elements needed for plant growth. Those same elements are present in the soil and available to the tomato plants. Adding a broad-spectrum fertilizer like Miracle-Gro boosts the nutrient level of the soil and in many cases, makes up for other deficiencies. It has never poisoned anybody. The cracks on your tomatoes are caused by variable weather conditions. Some cultivars are more prone to developing them than others.


Q: A tomato gets ripe on the plant and after it gets picked, it does not get ripe, it gets old, right? (E-mail reference)

A: Sounds like someone has a bet on this question so here is my answer: Mature green tomatoes will ripen after they are picked if placed in the right environment. Immature green tomatoes will not ripen no matter what, and will, as you say, simply get older, eventually rotting. Tomatoes go through some interesting biochemical changes as they develop to maturity and ripen, either on or off the vine. We are currently conducting research on tomato cultivars for acidity (pH), taste, and lycopene (antioxidant) content. We are initially finding that acidity varies little between cultivars and that they are not as acid as we once thought. We also think we are seeing a difference in the sugar and acid content based on weather conditions or location such as Fargo compared to Williston. Once tomatoes biologically mature, they have the biochemical capability of ripening, changing the acid/sugar ratio as the fruit ripens. A fully ripe tomato has a higher sugar content than one that is not fully ripe with no difference between the ripening taking place on or off the vine. I hope I answered your question to your satisfaction.


Q: I received a call from a lady about tomatoes. Her tomatoes have what she described as a black mold on the lower half of the tomato. The inside flesh of the tomato is brown and unusable. She says the plant itself looks healthy. The tomatoes are suspended and not laying on the ground. The disease information I reviewed didn't match the symptoms. She is concerned that she will have the disease in the soil for future crops. Any conclusions or recommendations? Thanks! (Napoleon, N.D.)

A: It sounds like delayed blossom rot having an effect on the whole fruit. This is a cultivar interaction with the environment, which is simply the fact that this particular one is not suited for growing in N.D. Normal garden clean up this fall and a new cultivar selection will likely solve the problem.


Q: I read an answer about an Oregon Spring tomato (nearly seedless). I was wondering if you could tell me where I might be able to purchase seeds or plants? (E-mail reference)

A: I think you would be better off, at this stage of the season, waiting until next spring. You can order seeds from Tomato Growers Supply Company, Box 2237, Ft. Myers FL 33902. Their phone number is: 1-(888)-478-7333.


Q: Approximately 70 years ago, my father grew a variety of red tomato named Red River, which I recall was hybridized by your facility. For many years seeds of this variety were cultivated by our family. It was our favorite. However, because of moves which precluded any vegetable gardening for a few years, we lost track of seeds for Red River tomatoes. (E-mail reference)

A: I have never heard of that variety of tomato, but perhaps someone will have some seed that they would be willing to share with you. If I get any kind of positive response, I'll connect the two of you.


Q: How do I fight existing tomato and potato blight? What can I do to prevent it? (Breckenridge, M.N.)

A: If it is just getting started, carefully pick off the infected leaves and dispose of them. Then, try to keep the water from splashing onto the foliage when watering. This can be accomplished with a soaker hose, drip irrigation, and/or generous mulch around the plants. If it is widespread, then fungicides need be applied. There are plenty of "garden" fungicides for you to select from at the local nursery or garden supply store. Finally, select those cultivars that are resistant to the diseases, and try to rotate the plantings with something that is not in the same family as the potato and tomato for about three years.


Q: I have no room for a garden but would like to plant at least one tomato plant in a large cedar planter located either on my deck or somewhere else in my yard. What tomato do you recommend? I would prefer something larger than a cherry tomato. Do I care for it the same as the tomatoes I had in my garden? Should I use garden soil or potting soil? Someone told me that when they used a large planter they put styrofoam in the bottom and then filled the rest with soil so the planter wasn't so heavy. Is this a good idea? (Ashley, N.D.)

A: No cherry tomatoes? Ok then here is a list of varieties that I have found tasty and productive. Many of which should be available at some local garden centers: Early Girl, Brandywine red, Celebrity, Oregon Spring, Prairie Fire, Health Kick, and Russian. Of course, if you can find Sheyenne around your area, that is an old favorite. About the only thing you need to be concerned with is the watering. Container gardens dry out faster than in-ground ones do. Use potting soil, not garden soil.


Q: I just read your column and noticed that someone is looking for Sheyenne tomatoes. We grow them where I work (at Harmens Greenhouse near LaMoure). We save the seeds each year and have a large demand for them. We wholesale as well as retail, so your inquirer may find them at a location near them. I'm sure if they contact Harmsens (701-883-5813) they would be glad to let them know of a source nearby. (LaMoure, N.D.)

A: You have no idea how happy you made many people in our area! Thanks for providing the lead.


Q: I am a long time gardener who has enjoyed starting my own seeds. I have had good luck with tomatoes called "Super Fantastic." The last several years I haven’t been able to find the seeds. Could you give me some information on where I might purchase the seeds? Also, what kind of evergreen trees could I plant that would not harm the apple trees? (Wolsey, S.D. )

A: Tomato Grower’s Supply has the tomato seeds that you are looking for. Their phone number is (888) 478-7333. The seed is listed on page 11 in their catalog. Any evergreen would work except any junipers.


Q: You had a request from a Moorhead resident about the Sheyenne tomato. Tanager Organic Seeds specializes in organically grown heirloom vegetable seeds. You can access the catalog at: www.angelfire.com/biz2/collectibles4u/seeds.html (Moorhead, Minn.)

A: Thanks! Your tip will make hundreds if not thousands of people happy. I checked the site out and it looks great.


Q: Would you have any information on a supplier of the Sheyenne variety of tomato? I can't seem to locate it. I have older friends that tell me how great that tomato was. ( Moorhead, Minn.)

A: I'm afraid you'll have to trust your older friends and their judgement. It was a good tomato, and still is, but is not available commercially anywhere that I know of. There might be some old-timers around who save the seed from year to year and would be willing to part with some, but I don't know who they would be. In the meantime, don't pine for the old days as there are dozens of other tomatoes readily available that are excellent in taste and disease resistance.


Q: I have a client who likes tomatoes but has troubles with the seeds because of diverticulitis. He would like information on availability of seedless tomato varieties that could be grown here. (Cavalier, N.D.)

A: There is no such thing, as far as I know, as a completely seedless tomato. There is one that is touted as nearly seedless, and we have grown it. It is called Oregon Spring and was developed by Oregon State University. The oxhearts are low in seed (just from experience) but this variety is the only one that touts seedlessness as a quality.


Q: This year almost all of my tomatoes split on top. The bottoms were fine. I kept them watered and mulched. Why did this happen? Also my ferns got brown and dry by the middle of August. I think it may have been from the hot wind. Could that be? (E-mail reference, northern South Dakota)

A: Sometimes it has to do with the variety of the tomato, and it usually affects the first fruit setting the most. I would suggest considering another tomato cultivar (variety) next spring, since it appears that you did everything right this year. Concerning the ferns, the wind could very easily be the cause. Some ferns are tough and will bounce back next spring, so don't give up hope just yet.


Q: A local farmer brought tomatoes and wanted to know why they developed yellow patches.  All have some degree of yellow on them. I'm sorry I don't have any information about the variety, etc. (Williston, N.D.)

A: The random yellowing is nothing to really worry about, unless one happens to be a nutrition fanatic. It simply represents a lycopene (red coloration) breakdown in the fruit and could be a result of the cultivar interacting with the environment (soil, watering, nutrients, weather conditions, etc.). Slice 'em up and enjoy, even if they are still a little deficient nutrition-wise


Q: What can I do to make tomatoes ripen faster? My plants this year had a lot of foliage. Should I trim that off and if so how much should I trim? Someone had told me not to water the tomatoes after they have set fruit. Is this true, or should I keep watering them? (Battle View, N.D.)

A: Tomatoes suddenly exposed to sunlight after being under a dense canopy foliage may just sunburn. They don't need sun on them to ripen. Yes, water stressing the tomatoes will cause them to ripen faster. Late in the season they should be able to get along on what mother nature provides anyway.


Q: Can you give me any information on tomatillos? How do they produce in North Dakota? When do they ripen ? (Bismarck, N.D.)

A: Tomatillos and tomatoes are both in the nightshade family, but different genera. The tomatillo is the genus Physalis while tomato is the Lycoperscion genera. Tomatillos grow fruit from large marble to golf ball size in a papery husk and are often called "husk tomatoes." There are several indicators of ripeness: the husk gets papery and straw-colored; or it opens; or, the fruit inside changes color from a green to a pale yellow. The tomatillo is used in Mexican cuisine to make a "genuine" salsa. They are generally simmered in water for five to10 minutes or roasted in a broiler until the skin blackens slightly to bring out the flavor before adding to salsa or other recipes. Leave the husks on when harvesting and storing. They will store longer. They often self-seed, so the following season will have some volunteers if they are not completely harvested in the fall.


Q: I am a first time tomato gardener(in a pot). The first tomatoes grew nicely and the last bunch were very small, just a little larger than cherry tomato size. Is this common? Also, how do I know when the plant will stop producing fruit? When that happens does it mean I throw the plant out, or does it come back next year? (E-mail reference, Dallas, Texas)

A: Your location makes a BIG difference. Thanks for telling me! Generally, tomatoes are thrown out at season's end. In the north, we don't have to worry about when that happens, as mother nature tells us with a killing frost usually some time in September. There are basically two tomato types as far as growth goes: determinate, where the plant grows to a particular size, produces fruit, and stops (some people refer to them as bush tomatoes), and indeterminate, where the plant grows as a vine, either sprawling all over the ground or up some kind of trellis. They continue producing fruit until the season ends with a frost. Concerning tomato size, no, smaller second fruits are not common on most tomato cultivars. It may be that since you have grown them in containers, the nutrient status is low in your soil. Tomatoes are heavy feeders, and need regular fertilization throughout the growing season, along with a steady water supply.

I am glad you have chosen to garden and selected tomatoes as your first crop. They’re the most commonly grown garden vegetable in America! I suggest you visit a local bookstore and look for "The Complete Vegetable and Herb Gardener," put out by the Burpee Company. It emphasizes organic approaches to gardening and is loaded with valuable information for both the beginner and professional.


Q: I have white spots on my tomatoes. When I bring them in the house, after a few days it looks like little holes in the tomatoes where the white spots were. What is wrong with them? (Williston, N.D.)

A: My best guess is that it is a disease like bacterial speck that attacks fruit in this manner, leaving black dots or holes all over the fruit. While unsightly, they can be cut out in most cases and the fruit still consumed. Try to avoid water splash on the fruit and foliage, and take care when working the garden that the disease doesn't get spread from one plant to another. Spraying with a fungicide at this time would be of no help. Cleaning up the debris this fall, rotating the planting site, and selecting resistant cultivars are the best approaches to preventing tomato disease.


Q: Can you please tell me what is wrong with my tomatoes. They always have enough water and I’ve raised tomatoes for years without problems. The leaves started to dry up from the bottom up and went all over the plant. I did spray with fungicide, but that didn’t help. Can you help? (Tuttle, N.D.)

A: From your description, it sounds like Septoria leaf spot. I am sending you some literature to read regarding the disease and its management. Don’t be too hard on yourself. It is normal to replant where you had good production the previous year, and this has been an ideal summer for proliferation of tomato diseases.


Q: When my tomatoes start blooming before the plant is well developed and bushed out, I pull the blossoms off to give the plants a chance to bush out more. My neighbor says if I do this I will have no tomatoes. Which one of us is right? (Audubon, Minn.)

A: I vote for your neighbor. I know many Master Gardeners and commercial growers of tomatoes who never follow that practice. They consider every bloom a potential tomato fruit!


Q: I started my tomatoes under grow lights in the basement. After the weather warmed up I moved them to the greenhouse. I have a disease infecting all six varieties of tomatoes. What is it? I sprayed it with Maneb. Enclosed is a sample for you to look at. Also, my spruce have something wrong with them. Can you please tell me what? (Regent, N.D.)

A: Your tomatoes are showing symptoms of phenoxy herbicide damage. It is either a contaminant in your soil or it has drifted in through your greenhouse ventilation system. The spruce samples you sent show symptoms of both needle cast and drought damage. Spray with Bravo (chlorothalonil) in June and July to control the needle cast. For the drought affected ones, water would solve the problem.


Q: We wish to plant a couple tomato plants on the east side of our garage. We realize this is not an ideal area for tomatoes since they will only get full sun in the morning but do not have yard on the south or west side to plant in. What would you suggest we add to the soil to prepare it as best we can for the young plants? Peat moss? (E-mail reference, Aberdeen, S.D.)

A: Not to worry. Tomatoes will do well with east sunlight against a home. I have seen it at least a half-dozen times. The early morning sun dries the foliage, the sun light and heat reflect from the side of the building, the plants get at least six hours of direct sunlight most of the summer, and they are spared the destructive heat of the late afternoon sun. Working sphagnum peat moss into the soil each year prior to planting can do nothing but improve the growth and production of your plants.


Q: I had blight in my tomatoes the last two years . Now I am wondering if there is a disease resistant tomato plant out there. If I take out the top 6 inches of the top soil, will that be enough to plant them back in the same plot? (E-mail reference, Hoven, S.D.)

A: That's too much work! Simply order disease resistant tomatoes. Any of the All-America Selection winners are resistant. Incorporate generous amounts of peat moss into the soil; water only around the base of the plant, not on the foliage, and stake them to keep the foliage and fruit off the ground. If you continue to have a problem after this year, get into a three-year crop rotation; beans, corn, then back to your tomatoes. That often breaks the disease cycle.


Q: I had a patron stop in today who starts her tomato plants from seed. Her question is,
what are some of the best varieties of tomatoes to grow in this area? (E-mail reference,
Valley City, N.D.)

A: There are probably close to 100 varieties of tomatoes that can be grown in North Dakota. Celebrity is one of the best hybrids as it grows with few problems and produces good sized (not jumbo) fruits. Others are: Sweet 100, Sweet Million, Better Boy Hybrid, Burpee Hybrid, Early Girl, Stupice, Siberia, and Better Bush Hybrid to name just a very few. Some are bush, some are indeterminate; some are large and some are small, depending on what the gardener wants. Good sources for the seeds are: 

Totally Tomatoes Catalog 
Fulfillment Center 335 S. High Street 
Randolph, WI 53956 

Tomato Growers Supply Co. 
P.O. Box 2237 
Fort Myers, FL 33902


Q: When should we start our tomato and pepper seeds? Can we just plant them directly outside in the spring? (e-mail)

A. Pepper and tomato seed should not be started yet! Figure about 28 to 30 days from the average last frost date in your area, and plant the seeds in a sterile media (like vermiculite) at that time. Be sure they get ample light from a flourescent lamp (about 6 to 9 inches above the seedbed), and bottom heat of about 72 F. As the seeds germinate, move the lamp up accordingly.

If we lived in a warmer climate, direct sowing might be possible. Simply put it out of your mind anywhere in the upper Midwest. Some may sprout, but the fruit bearing would be non-existent due to our short season.


Q: Help! The tomatoes in our community got sick this year. The tomatoes were half red and half green and spoiled too fast. I am a 93 year old grandmother and love to garden. (Rolette, N.D.)

A: The likely problem is a combination of factors; first, blossom end rot, followed by late blight fungus taking over. Try a different variety or two next year, plant in another location and hope Mother Nature cooperates with some decent tomato-growing weather!


Q: We had beautiful tomato plants loaded with fruit, but once they began to ripen the bottoms turned black and seemed to rot. This happened to about half of the tomatoes on every plant. What could be the cause of this? We do rotate the vegetables when seeding in the spring. (New Town, N.D.)

A: This is known as blossom end rot, caused by poor cell wall formation at that location. This, in turn, is brought on by surges in growth from excess moisture. Some cultivars are more resistant than others. Mulching the plants will often help nullify the problem.


Q: I have a problem with blight in my garden, on the tomatoes and potatoes. Is there anything I can do to get it out of the soil? I've been told to cover the garden with clear plastic and the sun will destroy it. Is this true? (Detroit Lakes, Minn.)

A: Oh, if only it were that easy! The best thing you can do are all of the following:

Be fanatical about cleaning up the garden debris this fall.  Rotate the crops--have beans, corn, carrots, or cabbage follow your tomatoes and potatoes.   Select resistant cultivars. Employ drip irrigation, or at least avoid watering overhead. Monitor regularly for diseases getting started. At first symptoms, apply a multipurpose fungicide.


Q: My garden is full of blight, the tomatoes have just the vines left, no leaves. Is there anything I can put on the garden this fall to prevent blight next season? (Jamestown, N.D.)

A: There are a number of steps you can take to help assure that your tomatoes will not be as blighted again:

Clean up all plant debris this fall, and if time permits, turn over the garden soil.   Select only those resistant tomato cultivars next season. Look for the letters V, F, N behind the names, which indicate Verticillium, Fusarium and nematode resistance.   Stake or cage your tomato plants next year. They typically are healthier, and produce better, along with having fewer disease problems. Avoid overhead watering or splashing water on tomato foliage. This contributes to more disease problems than most people realize. Mulch the plants with compost or sphagnum peat moss. This will modulate temperature and moisture extremes, and prevent or greatly reduce rain splash.


Q: Can you please tell me what to do with my garden plot that has had tomatoes with black spot or blight. To clean up this fall, can I spray with chlorine bleach? What do you suggest? (Fargo, N.D.)

A: I'm afraid that using bleach would alter the ecosystem too much. You're likely to get a rebound of something much worse! Instead, clean the area up physically as best you can, turn the soil over before winter if time permits, be sure to rotate your crops and select varieties that are disease resistant.


Q: Our tomatoes had a problem this year. The first fruit was okay, but that was all. Will it affect the soil for future use? We do rotate our crops every year and we use a lot of compost manure on it. (Karlsruhe, N.D.)

A: The tomatoes are showing an advanced stage of late blight--Phytophthora infestans. This has become a somewhat common disease on tomatoes this year, thanks to our rainy season. Clean up your garden carefully this fall, and turn the soil over. Plant resistant cultivars and stake or cage your plants. And of course, plant them where no Solanum crop was grown (peppers, eggplant, potatoes etc.).


Q: Can you tell me what is wrong with my cucumber and tomato plants? (Pettibone, N.D.)

A: Your plants appear to have the advanced stage of anthracnose and a bacterial leaf spot. First, I would suggest selecting only those plant cultivars that have disease resistance bred into them. Next, continue to rotate your plantings, tomatoes with beans, cucumbers with cabbage, etc. Avoid any overhead watering to keep this from recurring, and spray with a copper-based material to control further spread of the bacterial disease (if it hasn't developed too much). For the anthracnose, try Bravo or mancozeb as a protectant.


Q: Can you tell me why the leaves on my tomato plants are brittle, curl and have light-colored blotches? The problem seems to be spreading upward. I hope I can save my plant before it damages all of the green tomatoes on it. (Washburn, N.D.)

A: It appears your tomatoes are suffering from tomato mosaic virus--akin to tobacco mosaic virus--spread by handling (especially by smokers), leaf hoppers, etc. Unfortunately, there is not much one can do. If it is affecting only a couple of plants, then I'd suggest their immediate removal. If it is hitting many, then I suggest letting any green, mature tomatoes to ripen off the vine.


Q: My tomato plants were looking great and then this stuff attached itself to them. I did spray it with bordeaux mixture, but it didn't help. I enjoy plants, but I don't have any other place to plant them, so will this affect my plants next year? (Viborg, S.D.)

A: Your tomatoes have bacterial spot. It is a problem controlling diseases when you cannot rotate your crops. Be sure to clean the planting area completely of any debris, purchase disease-resistant cultivars and avoid overhead watering.


Q: Is it OK to put grass clippings around my tomato plants? (Oakes, N.D.)

A: Grass is fine, as long as no herbicides have been applied and you don't make the mulch more than 2 inches thick. Also, it is not advisable to spread wet grass around plants.


Q: I am trying to start a spraying program for blight on my tomatoes and I was hoping you couldmake some suggestions. (Maple Plain, Minn.)

A: You are smart to get a head start on these diseases. The NDSU Extension Service publication titled "Disease Control in Home-Grown Tomatoes" (PP-659) highlights what you need to do. Spray with chlorothalonil, mancozeb or maneb, and try to keep the foliage dry when watering.


Q: Every time my tomato plants get ripe they get black scab on them. I have to pick them green, then let them ripen. I planted them other places, but they still get that scab on them. One person said I water them too much or dig around them too much. Last year I didn't water them much, and they still got black scab. Is there something I can spray on the tomato plants? (Georgetown, Minn.)

A: It could be the variety of tomato you are planting. Do you save the seed each year? If so, that's your No. 1 mistake. Plant them deep, in full sun, and water only around the base of the plant, without splashing on the leaves. If you are a vigorous cultivator in your garden, try to stay away from the plants themselves with the hoe—hand weed around them. Also, try mulching your plants with organic matter this year to see if that helps.


Q: We are having a problem with our tomato leaves curling up, turning yellow and dropping off in the middle of July and August. Is there something I can do to stop this? I am also wondering what does lime do for the soil? Should I put some lime in my garden? (Mott, N.D.)

A: It sounds like verticillium wilt to me—a soil-borne disease. Your only defense is to purchase tomato seed with some letters after the names, like V, F, N (Verticillium, Fusarium and Nematode resistant varieties).

Lime is pretty much of little use in most of North Dakota. It is a soil "sweetner"—that is, it elevates the pH to more alkaline levels, something most soils don't need. I strongly suggest a soil test before any extensive fertilizer use. At this point, I do not recommend the application of any lime


Q: Is there such a thing as seedless tomatoes and cucumbers? (Carpio, N.D.)

A: Your question is a simple one, but the answers are tough. It took some calls to producers, and here is what I found. There are no seedless cultivars of tomatoes or cucumbers out there, but there are nearly seedless ones.

Your best bet probably is to call companies offering these cultivars. Two such firms are Stokes in New York, at 1-800-396-9238, and Tomato Growers in Florida, at 1-888-478-7333.


Q: I am trying to grow tomatoes inside hoping to have some ready to eat before we can plant them outside. Maybe even have fresh tomatoes year round. My plants grow to the two leaf stage then quit growing. What do I have to do to make them grow? I have a light on them. Is the soil too cool? (Manvel, N.D., e-mail)

A: You are finding out what many who invested much money into growing tomatoes commercially have found outit is not as easy as it looks!

Tomatoes are warm-weather crops. They need heat, and bottom heat is best. You can get some inexpensive heating cables or pads and place them under the plants. This will stimulate growth. Also, make sure the light is of the right spectrum. They need to be plant lights, of the fluorescent type, and kept close to the plantsabout 6 inches or so, no further! Keep the lights on for 14 to 16 hours, and when blooms appear, gently vibrate the tomato vines to aid pollination. Also, let the water set out for a day to warm up to room temperature. Coming directly out of the tap at this time of year is murder on the root system!

You should be able to do it; others have following this procedure. Good luck!


Q: I've started some tomato plants, and the underside leaves are starting to turn purple, curl up and die. I've powdered for bugs, but it hasn't helped. (Java, S.D.)

A: You are starting tomato plants about two and a half months too early! The purpling is a symptom of phosphorus deficiency. Check your planting mix for nutrient balance.


Q: I canned my tomatoes without salt, because my husband is on a low-salt diet. Now people are telling my that the tomatoes are not good because it is the salt that preserves them. Can we eat the tomatoes without getting sick? (Forman, N.D.)

A: Thanks for writing. I'm married to a home economics major who has canned tomatoes without salt for the past 14 years. Salt is an excellent preservative, but we are also hooked on its taste. Following normal good canning procedures such as clean containers, making sure of vacuum seals etc. will help preserve the fruit. Also, tomatoes are quite acidic, which helps in their preservation. Of course, dump any canned tomatoes that appear off-color, flavor or smell. Don't take a chance. In the future, refer to "Canning and Freezing Tomatoes" (FN175), which is a publication of the NDSU Extension Services.


Q: I am having trouble with my peppers getting a soft spot on one side. It looks kind of like blossom end rot that sometimes is seen on tomatoes. Is this possible and what should I do to stop this problem? (Hannaford, N.D.)

A: Peppers do indeed get a blossom-end-rot malady like tomatoes. Basically, the same treatment: mulching at time of planting, steady water supply, and cultivar selections that are not prone to the problem.


Q: Can you tell me where I can purchase some Israeli tomato seeds. It says in this ad that they are powerful in fighting cancer, and I would like to try them. (Rugby, N.D.)

A: Sorry I don't know where you can get the Israeli lycopene-enriched tomato. But, shame on whoever wrote the advertisement promotion! "...Farmers in Israel have come up with a hybrid tomato that contains between 4 and 10 times the lycopene content of regular varieties!" Now, just what is a "regular variety"? The ones that all the other seed companies have hybridized? I don't think they'd agree!

Be confident that all ripe, fresh tomatoes are rich in lycopene and will have the same anti-cancer benefits of the Israeli tomatoes. I would simply like to try them to see if they taste any better!

As a member of the Garden Writer's Association of America, I should be among the first to know when (or if) this product becomes available. When I do, I'll let everyone know through this column.


Q: Can you give me some information on dry rot of tomatoes? (Carrington, N.D.)

A: I assume by dry rot you mean blossom end rot. I've addressed the subject several times throughout the years and will be happy to do it again. Blossom end rot is not a disease per se (not caused by a pathogen), but a condition where insufficient calcium is available for complete cell formation at the blossom end of the fruit. This causes tissue breakdown, which results in the "rot" that is seen.

This is caused in some cases by wide fluctuations of water availability, cultivation or other root injury, and it is simply a characteristic of some tomato cultivars, with the first fruit to ripen being most vulnerable.

No sprays! Just maintain an even moisture regime, mulch, and select cultivars that are not prone to develop this malady.


Q: Enclosed are some leaves of two different tomato plants. Are they blighted or is there something else wrong with them? (Minot, N.D.)

A: Your tomato is blighted with Alterneria solani, a common fungus known as early blight. For control refer to enclosed PP659, "Disease Management in Home-Grown Tomatoes," where cultural and chemical controls are listed. Other readers may obtain a copy from any county office of the NDSU Extension Service, or by calling (701) 231-7882.

Basically, apply water at the base of the plants and avoid splashing, and use protective fungicides like Mancozeb or chlorothalonil.


Q: Enclosed is a tomato leaf which is affected by something. Every year about six weeks into the growing season this same thing appears. I have used different spray/powders, which don't seem to help a whole lot. This does affect the size and number of fruit they produce. I hope you can tell me what might be wrong. If so, how can I correct this problem? (Gettysburg, S.D.)

A: Your sample was well on the way to rotting (please everybody send me dry samples). But from what I could guess, it appears to be herbicide residual damage.

If this is not a possibility, then please send another sample, packed dry.


Q. Would you examine these samples of apple tree and tomato leaves and identify the problem they have?

I took a sample of the tree leaves to two nurseries. One said it was a blight and we bought the spray recommended and it didn't help. (Don't know what it was.) The other said it  was a fungus and sold us Daconil. That didn't help either. What would you recommend? Do the tomato leaves have the same problem? I would appreciate your help, I would hate to loose the trees. They are about 6 years old and bear apples every year.

I enjoy your articles. Thank you for your consideration. (Martin, N.D.)

A. The tomato plant has late blight, a relative of the blight that caused the potato famine in Ireland. Fungicides will not help at this stage. Try to plant in a different location next year and use resistant cultivars.

Your apple tree has scab and what appears to be a root problem. Application of fungicides must precede the appearance of the disease. I also suggest aeration around the dripline of the apple tree to possibly correct compaction, or other root anaerobic problems.

Enclosed is a copy of PP-659, "Disease Control in Home-Grown Tomatoes," and PP-454, "Diseases of Apples and Other Pome Fruits." Others may obtain copies of these publications at their local county extension offices or by contacting the NDSU Extension Distribution Center, Box 5655, Morrill 10, NDSU, Fargo, ND 58105-5655.


Q. Can you tell me if there is something to put on my garden ground before I plant next year? I have blight in my garden. It is on my tomato and cucumber plants.

Enclosed are the leaves. Please let me know what the disease is. (Pettibone, N.D.)

A. The disease is known as late blight or Phytophthora. There isn't much you can do about it now. The best bet next year is to get into crop rotation and avoid overhead or splashing water when irrigating.

I have enclosed extension circular PP-469, "Plant Disease Management in the Home Garden," which will also help you. Others may obtain a copy of this publication at their local county extension office or by contacting the NDSU Extension  Distribution Center, Box 5655, Morrill 10, NDSU, Fargo, ND 58105-5655.


Q. Our greenhouse tomatoes, grown hydroponically, are showing this leaf problem. Could you identify it and how to treat it?

Thank you. I always look for your column in the Sun Country paper. (Carrington, N.D.)

A. From the visual symptoms alone, I would say your solution is likely to be low in potassium. You definitely have some kind of nutrient salt imbalance. Have your water checked for naturally occurring salts, and adjust your nutrient input accordingly.

The variation in water quality over the period of a year is often overlooked with hydroponic growing.


Q.Enclosed please find samples of tomato leaves from early girl and celebrity varieties. It appears that the plants may have had some drift from 2,4-D spray. We do have tomatoes on the plants and it seems that the plants are getting to be more healthy looking. We are giving them a daily watering of Miracle-Gro and hope that this will bring them out of the set back.

We are wondering if it will be alright to eat the tomatoes from these plants. Thanking you in advance for your help. (Ipswich, S.D.)

A.The samples you sent definitely showed 2,4-D damage. I am sorry, but I cannot advise you to eat the fruits from the affected plants.


Q. Can you tell me what ails my tomatoes? I have sprayed twice with Mancozel plant fungicide. This affects nearly all of 100 plants. It seems that the bush tomato is less affected. (Lisbon, N.D.)

A. Your tomatoes are showing typical symptoms of phenoxy herbicide damage. It could be   the result of drift from adjacent field or turf applications, or residual in soil or mulch.


Q: I've read about grape tomatoes and the variety Santo or Santa. Do you know if they are hardy for our area, and what varieties would be recommended? (Cando,
N.D., e-mail)

A: You want to order the Santa hybrid, which matures in 55 days.


Q: I am having quite a bit of trouble with blight in my tomatoes and potatoes. Will the addition of copper to the soil help with the problem? I know of people in Williston that do apply copper and it seems to help. What do you think? (Amidon, N.D., e-mail)

A: Perception is everything, and if the copper seems to work, then so be it. But don't over do it, or plant toxicity will be the result. Copper IS a micro-nutrient, meaning that very little is needed for the effect desired--20 parts per million max. I would rather you apply the needed copper (and other micro-nutrients) through the use of a product like Miracid or something similar. That will reduce greatly the chance for toxicity.


Q: I have seen a number of products used to control early and late blight on tomatoes. These products are chlorothalonil, Daconil and captan. The captan is in powder form, and the other two are suspensions to be mixed with water. I have found that the water solutions or suspensions are easier to use and seem to cover the leaves of the plant better than a powder.
Which of these products do you recommend, and how often should an application be made? Are there any new products on the market at this time, and can these products be used to control apple scab and or the apple maggot? (Faulkton, S.D., e-mail)

A: The suspensions are better for coverage, and certainly less drift off target. These products would give some protection against apple scab, but being fungicides, they would do nothing for apple maggot. For the maggot you need Sevin applied at seven- to10-day intervals beginning at the end of June and continuing to about mid-September. This spacing would be good for the fungicide applications on the tomatoes as well. If the scab has already set in, don't worry about it this year. The apples are still edible. Practice good sanitation by cleaning everything up well this fall and begin spraying with captan next spring as the leaves unfold.


Q: What causes dry rot on a tomato? Is there anything that can be done to prevent the dry rot? Thanks for your help. (E-mail reference, Bowman, N.D.)

A: Dry rot, better known as blossom end rot, is caused by insufficient calcium being unable to reach the developing fruit at that end. Generally there is enough calcium in the soil, but sometimes over-zealous weed cultivating damages the roots and the plant is unable to take up enough calcium to transmit it to the blossom end of the tomato fruit. It also occurs after a period of no rain or irrigation, followed by rain and/or heavy irrigation -- a sudden surge of new growth in tissue. It is often confined to the first tomatoes to ripen; some cultivars are more prone to this problem. A solution is to mulch the plants to maintain even moisture levels and to keep from cultivating too close.


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