Questions on: Fertilizer

Ron Smith, Horticulturist, NDSU Extension Service


Q: I have five large dogs and a well-established shelterbelt on the west side of my two-acre lot. Would it be a bad idea to use the dogs’ solid waste as fertilizer for my shelterbelt? What should I know about spreading the piles? Should I mix anything with it, such as lime or tree mulch? I do nothing to the trees in this shelterbelt. I let the weeds grow and have not cleaned out fallen branches. Should I be doing these things? (Mandan, N.D.)

A: Spreading the dog manure on the shelterbelt planting would be a good way of disposing of the waste and certainly wouldn't hurt anything. I would suggest that you compost it with leaves or grass clippings to give it some fiber and dilute it somewhat.
I have spread chicken and cattle manure in my day and became used to the smell. If I could get used to the smell of accumulated dog droppings is another question. Of course, the more care you give the shelterbelt plantings, the longer they will last and reward you. Weeding and pruning would be just the basics to engage in on a regular basis.


Q: You specifically say not to fertilize trees and shrubs. My husband says the card that came with the bushes says to use Miracle-Gro Quick Start, and to drive Miracle-Gro Tree and Shrub Spikes into the ground around the tree. I believe you 100 percent, but I need a little “ammunition” to dissuade my husband from using any fertilizer or spikes. (e-mail reference)

A: Fertilizing trees and shrubs is not needed in 99 percent of the situations at planting time. In the old days when I was doing fieldwork as a landscape contractor, such fertilization was standard operating procedure. Then research was conducted at various universities around the country, most notably in Oklahoma and Virginia, plus others as well. It was found that such treatment had little positive effects on the plants when compared with no treatment. Fertilizers simply added to the expense. While a “shot” of Miracle-Gro Quick Start will not hurt anything and may lessen some transplanting shock (during the months of active growth) without adding significantly to the cost of planting, the use of spikes are a waste of good money. Have him take you out to dinner tonight or sometime soon because it will do the trees as much good. Spikes are not needed because they concentrate the nutrients in specific, tight locations, so the roots will spread randomly following the path of least resistance and mine the nutrients that already exist in the soil. Adding more nutrients blindly is like taking three vitamin pills when a qualified physician recommends just one. If a little is good, more must be better, which of course is wrong. Even in sterile soil, spikes still would be the wrong choice because the nutrients in the spikes would serve the plant much better evenly distributed throughout the backfill soil, plus the cost per unit of nutrient is the highest on the market. Everybody is marketing these darn things because the consumer is purchasing them, so why wouldn’t they recommend them? They do contain fertilizer and they can be driven right into the ground around the base of the trees, but the simple fact is they are not needed. It is like putting high-test gasoline in your car when regular will do the job, so why waste the money? This doesn’t make the companies that sell these products “bad companies” because they are simply responding to what the customers think they want. The companies are reading their market, responding to it and attempting to get a piece of that market for themselves. I can’t blame them for their business action, but it is my job to point out whether or not such action will benefit the consumer.


Q: I usually put about two drops of Liquid Miracle-Gro plant food in the water before I water my plants. I am afraid of overwatering. When I bought a new bottle, it didn’t say that it had chelated iron. Is this something important for the plant? My new bottle doesn’t have it. (e-mail reference)

A: Miracle-Gro fertilizer tends to acidify the soil somewhat, which makes the iron available to the plant. Most potting soil brands have enough iron within to sustain most houseplants. If the plant needs iron, it will tell you with interveinal chlorosis on the most recent growth. It easily is corrected at that time.


Q: Earlier this spring I requested manure for my garden. A farmer brought me too much manure and it was too fresh. Now my cabbage plants are not growing and the leaves on my tomato and peppers are turning yellow. Is there anything I can do for them? Will they snap out of it and start to improve? Some say give them lots of water and some say it will be better next year. What do you say? (Golden Valley, N.D.)

A: I doubt your plants will recover this year no matter how much water you apply. Give it a year to “weather” somewhat and next year’s crop should be fine.


Q: I am trying to figure out the amount of peat to buy. Do the 5.5-cubic-foot bags of peat fluff to more volume when it comes out of the bags or is that all there is? (e-mail reference)

A: Yes, those are compressed bails and the peat literally doubles in volume when it’s broken up.


Q: I have a flowering ornamental crab apple tree in my garden. The fruit doesn't fall off until spring and then I have lots of raking to do. This is difficult, since the plants in the garden are coming up so I have to rake around them. Should I worry about cleaning up the fruit? Will it decompose quickly if I just leave it? (E-mail reference)

A: The fruit that is falling off in the spring is probably smaller than marble size, and having gone through the winter, should be one step away from becoming compost. If it blankets the soil in your garden and you consider it unattractive, then pick up what you can easily and let the rest remain, either turning it into the soil or mulching over it with sphagnum peat moss or bark.


Q: Are there any studies on the various aspects of hardiness such as soil type, moisture, whether the cold comes early or late, is the cold worse when it's accompanied by wind, is it the branches or the roots which can't handle the cold, is it worse if there are large temperature fluctuations or extended cold spells? Does mulch help or hinder? What causes a variety to be hardier than others? Is it genetic makeup? If one raspberry plant out of 10 survived a hard winter, would the new plants from the one that survived be more able to survive subsequent cold winters? I really would like to know the botanical reasons rather than just take a company's word that a certain variety is hardy in zone 4. (E-mail reference)

A: Hardiness can be affected by nutrient level, water availability, whether or not the plant has time to acclimate to our changing temperatures and whether or not it can be "teased" out of a hardy state by fluctuating spring temperatures. If a single plant survives a brutal winter while the rest get wiped out, you can bet that plant will get a lot of attention. Was it a fluke? Seed will be collected to see if any of the offspring inherited a hardiness characteristic. Follow the dollars in some catalogs. They might say a species will survive in zone 4 because they want to expand their market.


Q: I know someone who is trying to raise blueberries. One question he has regards using ground up pinecones to lower the soil pH. Can this be done? We found some information about using sawdust. He does some woodworking and is concerned about using sawdust from plywood. (E-mail reference)

A: He needs 100 percent sphagnum peat and pinecones along with acidifying fertilizer. He should also select the hardiest plants he can find. I would stay away from the sawdust. It might have toxins from the glue and might cause chlorosis on the plants.


Q: I have access to horse manure but may not be able to get it until spring. Can I till it into the garden and plant at that time or does it need some time before I plant? (E-mail reference)

A: Horse manure is pretty hot stuff if it is used fresh. If it has been outside in a compost pile for a year, then it should be fine. You can then take and spread about three to four inches over your garden and till into the upper six to nine inches of soil, going in two perpendicular directions. If it has not been composted or aged somewhat, I would suggest using it with great care and in lesser amounts. You might want to get it tested for soluble salt content, pH, and nutrient analysis.


Q: Did you, this past summer, answer a question about putting pre emergent fertilizer on a newly seeded yard? Could you reprint the answer? (Frankfort, S.D.)

A: How I wish I was that organized! I get so many questions that I cannot specifically recall the one you're making reference to! But here is the low down on fertilizers for lawns. On new lawns, apply a starter material, which is higher in phosphorus and lower in nitrogen than normal.

For established lawns, do the spring fertilizer application around Memorial Day weekend. The fall application should be completed sometime around the Labor Day weekend. Do the winterizer application around Columbus Day.


Q: Every year I collect and burn at least a cubic yard of black walnut leaves. I understand that the trees or leaves are allelopathic to certain plants. Can I use the composted leaves in my garden? (Dent, Minn.)

A: I don't know if the allelopathic character would be carried over during the composting process. You might want to try a little around some tomatoes or peppers to see what effect it might have. I wouldn't suggest placing it wholesale on the garden until you experiment with it a little first.


Q: I've been putting Miracle Gro on acid loving plants like hydrangeas, azaleas, and dogwoods. The instructions say continue into the fall, even after the leaves fall. The instructions on their rose shrub package are silent on fall feeding. Does that mean don't apply it? (Jamestown, N.D.)

A: That is simply good marketing on their part. You need only about half as much fertilizer as they state to have decent looking, healthy plants. So stop! It isn't needed now for your woody plants, including the roses.


Q: I recently bought plant food spikes (Miracle-Gro 6 12 6). Can I use it on aloe vera, pothos and a new baby cactus hawthornia? (E-mail reference)

A: If you haven't opened the package, take it back and exchange it for granular or liquid houseplant fertilizer. No houseplant on the face of the earth needs those spikes continuously stuck into their root zone.


Q: I have a few thousand trees that I planted over the years. I plant a thousand or so each spring for deer habitat or cover on a couple of pieces of property that I have. I also have a number of trees in my yard as well. I get my fertilizer in bulk from the local grain terminal. A friend has used a handful of 30-10-10 for years which he seems to have good luck with so I use it too. I use a one ounce jar full per tree. I place it at the base of the trees which are covered by fabric. I’m not sure if this is hurting anything or not. I do it in the spring and sometimes in the fall. I also toss a couple of cups or more around the large spruce trees in my yard and one cup on my "B&B" trees. I have lost some trees in my yard but I believe fertilizer is not the problem. I have lost some to tree protectors, damage by a weed eater and because I have tried to grow zone 5 trees in zone 4. I won't try that again! Also I have a number of maples that have had plastic protectors on for a couple of years. I took them off this spring to find that some had lost a few feet of bark on one side. Did I leave them on too long?

A: Fertilizer placed at the base of a tree does little good. Your fertilization efforts, in all likelihood, are not benefitting the trees and, most certainly, they do not need the fertilization regime you are following. Tree roots are uncanny miners of nutrients from the soil. Fertilization is recommended, in most cases, only when deficiencies are suspected and can be confirmed with a soil or leaf tissue test. If fertilization is then called for, it is calculated by the spread of the tree. A precise amount is either spread under the canopy or injected into the soil at root depth near the feeder roots but not near the trunk where the roots are functioning as a prop for the trees. The fertilizer you are using is more suited for turfgrass than for trees. A lower level of nitrogen is recommended (10-10-10) so that leaching beyond the root zone doesn't take place or the tree isn't overstimulated into excessive foliar growth.


Q: A week ago I heard on our local news that we should not add gypsum to our gardens as it is too high in sodium. Is this true? Also, I need to move a lot of my peonies. When is the best time and do I cut them back before I move them? (Fargo, N.D.)

A: Gypsum has two elements, unless it has changed since I went to college, calcium and sulfur but no sodium. It is formulated to replace the sodium ion that has built up in soil with calcium to improve the tilth and drainage. It is only effective if adequate quality water can be added to the soil to leach the sodium ion out and replace it with the calcium. Peonies can be moved in early spring before they begin active growth.


Q: I have been using distilled water with a small amount of Miracle-Gro for many years. My plants seem to be okay but I wonder if reverse osmosis might be better. Am I giving my plants too much plant food? (E-mail reference)

A: Reverse osmosis (RO) water is all right for watering plants too. All the RO process does is remove most of the salts, generally down to about 10 parts per million, which is very close to distilled water. I think you may be overdoing it with the Miracle-Gro since you use it each time you water. Using it once every two weeks is adequate.


Q: I have large perennial beds (approximately 600 or so plants) with a few annuals mixed in around my home. I’ve been noticing some of the leaves are turning yellow. On the majority of them the leaves are yellowing and the veins are somewhat green. I am guessing they are lacking iron. I would like to send you soil samples of about three different areas in my beds. How much do you require and what is the charge? Also, what can I do to amend the soil? I have used a liquid iron formula that you attach to a garden hose. I will be adding a granular fertilizer and Miracle-Gro. (Not all at the same time, of course!) When I add new plants, I mix compost in with the soil. I will admit that I have been lax with composting in the fall like I should. I will compost now but should I do it again in the fall? Should I do something else? I mulch with wood chips. Should I clear away from each plant and compost or can I put the compost over the chips? How much should I use? Also, can you please tell me the difference between compost and humus? Is one better than the other? (Glyndon, Minn.)

A: The amount needed for the soil test lab is about a pint or a sandwich bag full. Get the pH, N,P, K, soluble salts and organic matter checked for each sample. The cost is approximately $20. Send it to the NDSU Soil Testing Lab, Fargo, ND 58105. You want to amend the soil based on the soil test results. The mixing of organic matter with the soil is always a good procedure. Compost is vegetable matter that has gone through a decaying and breakdown cycle that involves human interaction to move it along. Humus is another term for "woods earth" where the decomposition has taken place over the years (sometimes called "cold composting") and is composed of the plant material that has fallen to the forest floor. I really don't know that one is better than the other.


Q: Should I put Miracid (Miracle-Gro water soluble azalea, camellia, rhododendron plant food for evergreens and all other acid-loving plants) on my mugo, yew, globe arborvitae and my three Black Hills spruce this spring? How often? I couldn't actually find "Miracid" in the stores but this Miracle-Gro states "formerly Miracid." I have some brown on my Black Hills spruce evergreens and also on the globe arborvitae. (Grand Forks, N.D.)

A: Yes, it will not hurt to do so. Do it a couple of times this summer.


Q: What is the average shelf life for garden products like Miracle-Gro? I would like to know about powder and liquid forms of garden products. Does it affect shelf life if the products are kept in an unheated garden shed? (E-mail reference)

A: The powdered product should last virtually forever. I’m uncertain about liquids if the shed is subject to freezing. I wouldn't take a chance as separation could take place or a chemical reaction could occur that would change the composition of the material. Most of those liquids have a definite shelf life, usually at room temperatures in the 60 to mid-70s range. I would suggest that if you have doubts or concerns that you contact the manufacturer of the particular product.


Q: We are going to use our fireplace this winter. Would it be beneficial to use the wood ash on our lawn? If so, do we spread it as soon as it cools during winter, or should we collect it and wait until spring? Also, do we simply distribute it by hand on top of the lawn surface (is it effective without being incorporated into the soil)? (E-mail reference)

A: I would suggest storing it dry until the spring thaw. Frozen ground doesn't absorb nutrients and mixing the ash with wet snow will degrade some of the nutrients the ash contains. Spread it at a rate of about 5-10 pounds per 100 square feet. For maximum effect, do right after a core aeration of your lawn. Otherwise the potassium will work it's way into the soil slowly with the spring and summer rains.


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 gardener asked me for the recipe for manure tea. Do you have a recipe? (Cando, N.D.)

A: Manure or compost "tea" is simply the liquid that is collected from compost or well-weathered manure piles. A cheese-cloth or untreated burlap is used to filter the solid stuff out. Soak this "bag" of compost or manure in a watering can or barrel for a couple of days, then dilute it to a weak-tea color. Reuse a couple more times, then use the solid material as a mulch or to condition the garden soil.


Q: A lady asked if she could spread her fireplace ashes on her garden. Would it help, hurt, or do nothing to her crop? Next, a man asked if there was some chemical he could use to kill a young chokecherry tree growing too close to his house. (Bowman, N.D.)

A: A one-time application of ashes will not hurt, but a continual application would do no good. The pH of ashes is alkaline, something most soils in North Dakota don't need. To kill the chokecherry, allow it to leaf out, then paint or spray the leaves with Roundup.


Q: My question is about the effects of potassium nitrate (Greenlight Stump Remover) on adjacent trees. If placed in a hole approximately 4 feet from 2- to 3-year-old blue spruce, will we see some leaching and subsequent damage to those trees? (Hettinger, N.D.)

A: Your question leaves me a little confused: potassium nitrate (aka saltpeter) is used in tree stumps along with paraffin and slowly burned out of the ground. Otherwise it is a fertilizer. Are you placing it in the ground or the stump of a tree? Either way it shouldn't damage the adjacent spruce, unless it is over-applied, and that would only result in localized root damage, not the killing of the whole tree.


Q: How much wood ash can a person put on a garden? It seems to me that we have a lot of soluble salts in our soil here, and more in the water, so that the addition of ashes would compound the problem. What's your opinion on this one? What about using a combination of manure and ashes? (Beach, N.D.)

A: Adding wood ash is OK as long as the soil is acid or low in potassium. Wood ash itself is highly alkaline, and I suspect that the soils in your areas are as well, so adding wood ashes to your soil would be a redundancy and inhibit micronutrient uptake by plants as well as micronutrient activity. The salts would come mostly from the manure source; adding wood ashes to manure piles would contribute to controlling odors, increase the calcium and potassium content and the pH to possible toxic levels.


Q: I have access to several bags of "decorative" redwood bark. Can I use it as mulch (raking it off at the end of the season) without harming the soil or vegetables? (E-mail reference)

A: It shouldn't hurt anything as long as it isn't placed around the plants in excess. Two to 3 inches should be all right. Don't put it directly against the stems of the plants. Leave about a 1-inch clearing to prevent disease girdling the stem from continuous moist contact.


Q: I have recently taken on a project investigating the composting of poultry feathers. Before I tackle the issue I am researching the techniques of composting and what factors make a good compost. I have investigated the moisture content and the carbon to nitrogen ratio. (E-mail reference)

A: You need to get your hands on two books: "The Rodale Guide To Composting" and the "Science and Engineering of Composting" edited by Harry A.J. Hoitink and Harold M. Keener, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH.

If you can’t find the answers to your composting questions in these two books, I doubt you'll find them anywhere else!


Q: I think my soil is lacking phosphorus. What is the best natural (organic) or otherwise phosphorus to use? When do I apply it? Also, where do you recommend sending a soil sample for testing? (Bonney Lake, Wash.)

A: Rock phosphate is the natural source. Superphosphate is treated with sulfuric acid to make the phosphorus more readily available. It is best applied into the soil in the fall, to give it time to become available the following spring. Work it into the upper 6 inches, using about 40 pounds per 1000 square feet. For soil testing, your best bet is to contact your local state university, requesting their soil test lab. The price for a fairly complete soil test (N, P, K, pH, soluble salts, Ca, Mg) is usually between $20 and $30.


Q: I'd like to offer another idea for the woman who wrote that her husband dumped left-over minnows on her lawn. You suggested that the fish go to the compost pile. Being an organic gardener for awhile now, I think that may cause some problems. Any time animal products are put in the compost pile it attracts vermin, and lots of maggots! It's pretty much taboo to ever put any meat, even vegetables with some grease on them, in the compost. An alternative would be to dig under the compost and bury the fish in about a foot or more of dirt (my parents saved several trees on our land by burying the leftovers of fish cleanings under ailing trees). By the next year that dirt will be very fertile and ready to use in the garden. (Jamestown, N.D.)

A: I know that but didn't think of it at the time! Thanks for the tip and reminder.


Q: My husband and I argued over this one. This winter he would dump his dead minnows on the lawn after his fishing expeditions. I think this kills my lawn and he argues that it fertilizes the lawn. Which one is it? It seems like the area in which he dumped the minnows the grass is still brown and not growing very well at all. Hopefully you can settle our argument. ( New Rockford, N.D.)

A: I think I should change my name to Solomon, since I get so entangled with solving spousal arguments! Here is my answer: You are both right. The minnows act as a fertilizer eventually, but the water he dumps with the minnows temporarily thaws the snow enough to encourage snow mold pathogens to develop, resulting in the dead areas of your lawn. It would be better if you had a compost pile that he could dump the minnows on, allowing them to be digested by the microbes into compost, which is certainly more useable and not as unpleasant as seeing dead minnows strewn about on the lawn. I hope this brings peace to your marriage!


Q: During clean up there will be lots of old wood and brush to be burned. Since most of the minerals will remain in the ashes, can it be used for fertilizer, and how? Seems to me we used to make soap by pouring water thru wood ashes for the "lye" component, so I imagine ashes would tend to make the ground highly alkaline. (Bismarck, N.D.)

A: Yes, ashes can be used as a "fertilizer," and yes, they are very alkaline. I would suggest mixing just a little into the upper part of the soil--1 inch covering into 4 inches of soil--and see what results you get. If your soil is already quite alkaline, you will likely not notice any difference.


Q: Could you send me some information on how to fertilize my apple tree? My tree is 40 to 50 years old and I believe it needs fertilizer of some kind. (Napoleon, N.D.)

A: Just because your apple tree is 50 years old doesn’t necessarily mean it needs fertilizer. If your tree is growing in a turf area that has received regular fertilization, the tree’s nutrient needs have likely been met. About the only thing apple or other fruit trees need in much of our region are the trace elements, iron, zinc, copper, etc., since they are "tied up" at the elevated pH of our soils.


Q: I read not to use dog manure in a compost as it may carry disease. Yes or no? Also, should cow or other manure be aged or can it be fresh? I know that commercial fertilizer can be used as a replacement. (E-mail reference, Fessenden, N.D.)

A: If it did carry disease, a "hot" pile of compost would kill the organism as the temperature gets to 140-160 degrees F. Never use manure fresh. Salts are too high and the carbon/nitrogen ratio could be a problem, tying up the available N, causing chlorosis.


Q: We recently purchased a contorted filbert. What type of fertilizer or plant food should we use and how often? Can the suckers be dug up and transplanted? Are catkins the little green things that hang down from the branches? What is their purpose? (E-mail reference, Gilbertsville, Ky.)

A: I wouldn't worry about fertilizing this tree, unless you have it growing in a container. Then it should be a complete fertilizer like Miracle-Gro once a month. Otherwise the tree will do just fine in the soil that it is planted in. I would water only when or if, the plant shows some nutrient deficiency symptoms. Yes, the suckers can be dug and transplanted, but being a grafted plant, you will not getting the same thing. Suckering is one of the problems with this plant. Yes, those are male catkins hanging off the branches. They serve as a source of pollen for the female flowers, which almost never show up, so their purpose is mostly ornamental. Don't hope for any filberts! This is also known as Harry Lauder's Walkingstick. It was discovered in 1863 at Frocester, Gloucestershire, England, in a hedgerow.


Q: In a recent Hortiscope you indicate that sunflower hulls are inert. Another horticulture specialist claims they contain an allelopathic substance that will inhibit growth of nearby plants. I know sunflower roots are allelopathic, and when we spread sunflower hulls at Crookston we could essentially sterilize the ground if we put them on heavy enough. Any thoughts? (E-mail reference, Beach, N.D.)

A: Well, that is interesting anecdotal evidence that something is working, either chemical or physical. A good little study would be to take water extracts from sunflower hulls and spray it over some soil to see if the same effect is obtained. I would really like to know, one way or the other.


Q: I received a beautiful plant for my birthday called a Kalanchoe (Kalanchoe blossfeldiana) I keep it in my office. It seems to like the fluorescent lights. The card says to maintain soil on dry side and to fertilize starting two to three weeks after purchase. What type of fertilizer should I use? We just noticed that there are two plants in the pot. Should I divide them? It is a fairly large plant, the blossoms (dark to pale pink) seem to still be okay. People comment on the plant when they come in and I don't know what to tell them. I can't even pronounce the name! (Mandan, N.D.)

A: What a nice gift to get! They are beautiful plants, and are easily cared for. There are any number of houseplant fertilizers you can use. Shop locally and see if they have Schulz's, Miracle-Gro, or Hyponex. Those seem to be the most popular ones on the market. I have used all of them to satisfaction. For care, I suggest dividing it when it is dormant, which will occur later in the spring. Water thoroughly each time, allowing the soil surface to dry between waterings. Being a succulent, it propagates easily. Simply take cuttings in the fall and root them. Once it has finished flowering, it will be a challenge to get it to root again, as it has a low temperature requirement to do so (50 degrees). But even as a succulent without flowers, the plant is attractive. And, as far as pronunciation goes, sound it out phonetically, and call it that. Who is going to argue with you?


Q: My brother helps out on a horse farm on his days off. They have a lot of pine shavings mixed with manure that are really piling up. He has hauled a lot of it off the place but he would like some information on how to break down the shavings faster. Are there any commercial composting agents that would help break down the shavings? Or something else? (E-mail reference, Bozeman, Mont.)

A: What is needed is to get the "N" in the C/N ratio higher, and he can do this if he adds some commercial nitrogen to the mix, or simply collects some grass clippings from golf courses or lawn care operators who mow lawns for a living. It depends on the size of the pine shavings, too. The finer they are, the quicker they will break down. Even if they don't break down to unrecognizable components in the pile, one summer of weathering will usually do the job at rendering them ineffective in tying up available N. At that point, the end user has nothing to worry about.


Q: Do I really need to put fertilizer on my trees? If so, which one do you recommend? (E-mail reference, Milpitas, Cal.) 

A: Fertilization of trees is suggested only in response to a deficiency. Generally, trees need little additional nutrients, since they have an extensive root system to mine ample nutrients from the soil. If you start to notice chlorosis (yellowing of the foliage) or shortened internodes on the branches, then it might be advisable to add a complete fertilizer like a 10-10-10 or one that contains microelements like iron and copper. To know where your soil stands in nutrient content, I suggest getting a soil test done. Have the pH, organic matter, N,P, and K and the soluble salts checked.


Q: I need to know what kind of manure is best to use as fertilizer for a strawberry garden. Also, would marigolds and/or Hoya Carnosa help keep harmful bugs away from my strawberries? (e-mail)

A: The best manure is rabbit. It is clean, easy to handle and, of course, rich in nutrients.

The lygus bug is the big pest with strawberries. It damages the flowers and causes "nubbins" to develop. I doubt the flowers you mentioned would be effective in keeping these and other destructive insects away.


Q: I'm am wondering where can you buy Poast in small quantities, and also lime to use on trees for fungus. (e-mail)

A: Poast is not available in small quantities that I am aware of, but lime sulfur should be available at just about any garden supply store, garden center or retail nursery.


Q: When a granular form of fertilizer or nitrogen is added to an existing flower garden, do you just sprinkle it on the surface and water it in? Will the fertilizer eventually trickle down to those roots, or do I need to do something different around those plants? I want to be sure that all my flowers get what they need as not all have done so well the last year or two.

Also, do I need to apply the nitrogen more than once a summer?

One more question! I often read about how many gardeners are always incorporating organic matter into the soil. I add peat moss to my soil whenever I plant new plants, but how does one incorporate organic matter around existing plants? If I dig around the plants do I risk damaging roots? Is it good enough just to spread the organic matter across the surface? (e-mail)

A: Nitrogen sprinkled on the soil surface as a granular fertilizer will move into the soil profile and become available to the roots with the irrigation water or rain. Of course, if the soil is as hard as concrete, it will simply wash off. If it has good tilth, it will work well.

During a normal growing season (whatever that may be!) it is a good idea to apply nitrogen-based fertilizer about once every four to six weeks, assuming you are going to water and care for the planting on a regular basis. I wouldn't go beyond Aug. 1, however, as it would mostly be wasted.

If you work organic matter into the soil away from the roots of the plants and simply spread it around the plants that are already established, that will benefit the plants and the soil greatly.


Q: Can you tell me how to mix packages of Tempo insecticide with water? Also, I bought a Mandevilla vine last spring and it has been doing wonderful. What do I do with it for the winter? Do I need to cut it back? (Minot, N.D., e-mail)

A: Concerning the Tempo insecticide, the label does not give specifics: "Mix one 50-gram packet of TEMPO 20 WP in sufficient water to adequately cover 5,000 square feet." I would suggest nothing less than 5 gallons of water, but I also suggest spraying the area with water first to see how much will be required to cover the area to the point of runoff. Be sure you handle the water-soluble packets with dry hands or gloves.

Concerning the Mandevilla vine, if it has stopped flowering, then cut it back now and repot in the spring. It will need bright, indirect light to keep it going through the winter. Do not overwater during the winter months, but mist it often when the air is dry from heavy interior heat use. Don't let it experience temperatures lower than 55 F.


Q: We have a fairly large patch of strawberries, but have been getting few berries out of this patch. What type of fertilizer should we be using and how often? Also, what should we use for weed control? We also have a large patch of raspberries along the south side of our garage and we've always gotten quite a lot from them except this year. Is it possible that this patch is dying out? It is more than 10 years old and, we have never done anything with it except to cut out the dead canes. (Barnesville, Minn.)

A: Your strawberries may very likely have a virus disease, one of the symptoms of which is a yield reduction. They and the raspberries should be fertilized twice a year; once in the spring at initial growth or green-up, and again right after harvest. The material to use is 5-10-5 at about 10 to 15 pounds per 100 square feet.

Raspberries just don't "die out" unless something is killing them. It be virus, root rot, cane cankers, anthracnose, cane borers etc.

Both crops require constant attention to good management practices to be sustained productively. For example, the old mother strawberry plant should be tilled up each year, allowing the daughter plants to be more productive. The following year, those daughters are tilled and so forth.


Q: I have five maple shrubs, but only one has the light color veining its leaves. What nutrient is lacking? Is it too late in the season to fertilize? In general I have been using Miracle-Gro. Should I be using something different? (Washburn, N.D.)

A: I doubt that any fertilizer will pull your Amur maple out of its chlorotic funk. Generally, when a tree is stressed, it shows an iron deficiency--which yours is doing. I suspect a root rot problem of some type. Although you will not get any response now, put some chelated iron into the soil around this tree, and hope next spring it can outgrow whatever is ailing it. If the same symptoms appear with the growth next year, get the tree out of there, root and all.


Q: Will fertilizer spikes last over the winter? (Garrison, N.D.)

A: I know of no reason why the spikes shouldn't keep for another year, as long as they are kept dry.


Q: I found this powder substance in ice cream pails in a neighbor's garage. They said they thought it was for use on evergreen trees, but I'm not sure. (Leonard, N.D.)

A: The material appears to be a water-soluble fertilizer like Miracle-Gro. You can dissolve 1 teaspoon in 1 gallon of water to apply to plants. Evergreens generally don't need fertilization, so be careful to not overdo.


Q. In a previous column, you recommended that Miracle-Gro be used on arborvitae. We have both products: Miracle-Gro and Miracid. The recommendation for evergreens is to use Miracid. Please address this matter in a future column.

We have benefitted so much from the information in your columns and take your advice as "gospel" the good news so please help us in this one also. Thanks. (Lisbon, N.D.)

A. Miracid is used where soil acidification is needed. It does this gradually, by the action of soil microorganisms breaking down organic compounds.

The length of time required to produce the acid reaction depends on the amount and frequency of application of the product, along with soil type, temperatures and moisture conditions.

Like its "mother product" Miracle-Gro, there is no danger of harmful residual buildup and certainly in our region, no danger of making the soil too acidic. Miracid is often recommended where iron or other trace element chlorosis or deficiencies are noted in a crop or planting that are not corrected by the usual methods.

Like Miracle-Gro, the product's nutrients are quickly utilized by the plants through foliar application hence the quick but non-leggy response.

I didn't mean to neglect this important product to gardeners. I am fortunate enough to not have chlorotic plants and have found Miracle-Gro to give me the results I want.


Q. I have a Globe Arborvitae that has a brown bud-like growth which has been present for the second year. The plant looks sickly and is turning yellowish-brown, although there are still some healthy looking branches left. It appears to be some type of disease. I have been on the verge of digging it up and starting from scratch again. Do you have any suggestions as to what the problem is and what can be done with it?

I have enclosed a couple samples for you to examine. Thanks for any help you can give. (Center, N.D.)

A. Nothing to worry about--that is just the arborvitae "fruit" or seeds.

If it is producing heavily, that is often a sign of plant stress, not at all unusual in North Dakota. You might try fertilizing with Miracle-Gro. If you are using plastic mulch in your planting beds, remove it--the roots need air.

Consider relandscaping with something different. Refer to the circular H-958, "Landscape Ideas for North Dakota Homeowners," available from any office of the NDSU Extension Service.

Thanks for writing.


Q. How is one supposed to water plants with Miracle-Gro; spray type or root way?

My strawberries were winter hurt two years ago. They didn't do anything last year, and by the looks they will not do much this year. Should I dig them all up and get a new set, or is there something I can do to bring them back to bearing again?

Thank you for all the good information you supply in the paper. (Linton, N.D.)

A. Miracle-Gro is applied as a liquid spray over the foliage where it is rapidly absorbed by the plant. It appears to have been a bad year for strawberries--thanks to our long, tough winter. At this point, I would suggest starting over (see circular H-16, "Strawberries") to get something productive that is worth picking.


Q: What kind of fertilizer is best for my cucumbers and pumpkins, as far as high yield and early yield goes? I can order 25 pounds of 20-20-20 all-purpose fertilizer from one place for $24.41. Another option is 5 pounds of Miracle Grow (15-30-15) for $14.95. What kind of yield per season could I expect from 100 asparagus plants once they're established? I know it depends on about a million things, but could you just give me a ballpark figure? I've read you shouldn't start cucumbers or pumpkins to transplant more than two or three weeks before you set them out. Do you agree? Would you set them out about May 20 (I live near Jamestown) or is that still iffy since they are so tender? I will have black plastic down and cloches above them. (Jamestown, N.D., e-mail)

A: I prefer Miracle-Gro. It has a good spectrum of major and minor elements that others lack and doesn't cause excessive vegetative growth.

Asparagus should yield between 40 to 50 pounds per 100 plants.

The longer the cucumbers and pumpkins sit around waiting to be planted out, the more difficult it becomes to get them established. May 20 is still iffy, but gardening any time of the year in North Dakota is iffy! With the plastic down and clotches above them they should do OK.


Q: Is it OK to use gypsum to reduce salt and pH? I am having trouble getting trees to grow and have found a site on the Internet that recommended this. What rate or how much should I use? (Wahpeton, N.D., e-mail)

A: That is poor information--or at least incomplete information. Gypsum, which is essentially calcium sulfate, is close to neutral in pH value. Second, in order for it to be effective, it has to be placed on a soil that is high in sodium (Na) to have the calcium ion replace it. Third, adding gypsum or anything else will do little to no good if the salts cannot be leached from the root zone or soil profile. Most soils in the Red River Valley are from a calcium carbonate base, so there is plenty of calcium already present, and unfortunately, most of the soils are poorly drained. If, by chance, your soils are well drained (which I doubt), then adding gypsum might help, if I knew what the amount of sodium per acre was. For every 23 pounds of sodium present in the soil, 20 pounds of calcium is required to replace it. For example then, if a soil test showed 402 ppm (parts per million) sodium, or 804 pounds per acre, roughly 700 pounds of calcium per acre would be required to make the replacement (804 pounds of sodium divided by 23 times 20 = 699). Since gypsum is about 29 percent calcium, it would take 55.3 pounds of gypsum per 1000 square feet to make the replacement. This should be worked into the upper 6 to 9 inches of soil prior to planting, followed by 12 inches of irrigation water applied over a two week period to leach out the unwanted sodium. I know this is more information than you wanted, but I was trying to show that answers to such problems are not simple, but complex. I suffered through many hours of soil physics to learn this stuff years ago--and back then I was really wishing it was simple!


Q: I just planted four rose bushes, all being hybrids, and they are in good sun, but out of four one went into shock (I think) from being transplanted, even though I used Safe vitamin B1. I am constantly having problems with my plants going into shock, especially hydrangeas. I usually have to deadhead all my flowers and a handful of leaves after transplanting. Is there something I am doing wrong or is this just to normal? Also, I was wondering if fish emulsion is really that great of a fertilizer. I use it on all my plants, but I want an experienced opinion. I have some well-decomposed steer manure, but I was told by someone less experienced than myself not to put it in this time of the year because it will burn the soil. True or false? (e-mail)

A: Generally, the shock you describe is normal. Most hydrangeas are greenhouse grown under ideal conditions, and when they are moved into real world settings, the show their distaste by dropping leaves etc. As long as they come out of it, don't worry. The fish emulsion and the composted steer manure are both fine for use in the garden. Both are low in nutrients and would be almost impossible to get a burn from either, unless someone spiked them with some extra nutrients to make them more potent! Use either without worry!


Q: Do you know of a fertilizer product (supposedly applied to lawns) that you can sprinkle on your sidewalk to get rid of ice? We don't want to use salt. (E-mail reference)

A: Any dark-colored fertilizer will do the trick -- somewhat. No deicer works when the temperatures reach the sub-zero level. Mixing it with coarse sand will help as well.


Q: Do you have information in one an Extension publication on how, when and with what to fertilize fruit trees? (E-mail reference, Forman, N.D.)

A: No, we do not. Fruit trees (like most other trees) need little if any fertilizer. If some is needed based on a diagnosed deficiency symptom, then I suggest that the missing nutrient(s) be added at the recommended rates. This is usually done for farms that are in the apple orchard business. For the backyard fruit lover, I suggest an early spring application of 10-10-10 or something similar under the drip line of the canopy. Do this just before the leaves unfold. The deficiency I have seen in our high pH region of the country is possibly of micronutrients. iron, zinc, or copper, determined by a soil and tissue analysis.


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