Questions on: Squash

Ron Smith, Horticulturist, NDSU Extension Service


Q: I have a question about buttercup squash that I grew in my garden this season. I live in the northwest part of North Dakota. My garden is under an irrigation pivot in the corner of an alfalfa field. The buttercup squash grew beside two other types of squash, spaghetti and acorn. My squash has white, raised spots that resemble seeds on the outside skin. The water that we irrigate with is high in sodium. What caused these spots? Is this squash safe to eat? Do I need to do anything special to the squash in order to make it safe to eat? (e-mail reference)

A: Those are corky lesions on the skin of the squash, which are nothing to worry about. The lesions will not affect the eating or storage quality of the vegetable. This comes mostly from physical damage, such as insects, hail or wind-blown dirt.


Q: I planted a row of squash that is now rotting at the bloom end. What should I do and what is causing the problem? What do I need to do to prevent this from happening again? (e-mail reference)

A: The problem is blossom end rot on squash. This is the same problem that occurs with early fruit set of tomatoes and peppers. The problem should disappear as the season moves on and other fruit is set. It is caused by sudden changes in the water supply, such as going from very little water to a sudden abundance. It also can be caused by vigorous cultivation. This damages the roots and limits their ability to absorb nutrients. This results in incomplete cell formation at the end of the fruit, cell tissue collapsing and then secondary organisms moving into the fruit.


Q: Why do the little pumpkin and squash fruits turn yellow and fall off, sometimes before the flowers open? My summer yellow squash does not have this problem! I try not to overwater, but the plants wilt in the sun, so a little splash of water revives them. (Fargo, N.D.)

A: The flowers were not fertilized because of the lack of bee activity in your area.


Q: I read that if, at the first part of October, you feed your Christmas cactus a solution of two tablespoons castrol oil and one-half cup lukewarm water it would bloom before or at Christmas time. Is there any truth to this? I don't want to kill my plant as it came from a clipping of a cactus that was brought over from England over 125 years ago. I also must be the only one from North Dakota that can't get zucchini to grow. They bloom, produce a few squash, and the rest of the blooms either fall off or don't produce. They are in an easterly direction, where it gets early morning sun and plenty of water from the roof of a building when it rains. I also water often.

A: The Christmas cactus will come into flower when its need for short day length has been satisfied. I have never heard of using castrol oil and advise against it. You must be the only one I've ever known that can't grow zucchini! It may be the rainwater from the roof, otherwise, I don't know!


Q: Im raising winter squash. When should I stop watering it and how do you tell when the squash are ripe? Also, can you water cucumbers too much? (Opal, S.D.)

A: The squash vine roots are extensively developed by now and should not need further supplemental watering. Ripe winter squash will have a shell hard enough to resist pressure from a thumb nail. Id let them stay until frost hits the vine. Yes, you can certainly water cucumbers too much!


Q: I had a fellow ask me a question regarding a problem with his squash plants last summer. They would get squash anywhere from quarter to half dollar size and then the small squash would dry up. I had the same problem with my birdhouse gourds. I've searched all my books and information from the master gardener class and can't seem to find anything on it. Can you give me any help? (E-mail reference, Williston, N.D.)

A: This usually means that the pollination of the squash was either incomplete or non-existent. It happens when the stigma is ready to receive pollen and there is no male flower to supply the pollen, no insect to transfer it, or the weather is not conducive to pollination at the time the plant organs were ready.


Q: All of my squash, gourd, pumpkin, melon, and cucumber plants have begun to die. It begins with one runner wilting and yellowing and then proceeds to the entire plant. There are no bugs, ground rodents etc. visible. Plants have been sprayed and fertilized. The plants are scattered throughout the garden and were not previously planted in current locations. Any ideas? (Avon, S.D., e-mail)

A: It sounds like Verticillium wilt to me. This is a fungus of the root system that attacks plants under the right environmental conditions, and we are seeing a lot of it this year--on cukes, squash, flowers, trees and shrubs. All you can do is remove the dead plants this year, and plant resistant cultivars next year--looking for the initials VFN after the names, which indicates Verticillium, Fusarium, and nematode resistance.


Q: Can you tell me what is wrong with my sunflower and squash leaves? They seem to have a grayish discoloration. I also bought what I thought was a kobold blue liatris, but it looks like a garden weed. Is this what it should look like? (Moorhead, Minn.)

A: Both plants have a bad case of downy mildew, and the weed is giant foxtail. Spray plants with Daconil in the spring to prevent onset of the disease, and repeat monthly. Control the weed with a preemergent herbicide.


Q: When I planted my squash last year I got some fresh manure and put some in each hole with the seed. At harvest time I got some squash but not very many.
When I pulled up the plants in the fall there appeared to be not much of a root system. Did I do the wrong thing? (Audubon, Minn.)

A: The manure was not a good idea. It is often high in soluble salts and weed seeds. The salts are what kept the roots from developing.


Q: Last year toward the end of the season I had squash beetles, so I removed all the plants and sprayed with Malathion at the end of the season. I then removed all the mulch and sprayed again. This year I noticed that they were back early and I sprayed with Malathion again. How much should I use of the Malathion to a gallon of water and would it be ok to mix it with Sevin as I use Sevin on the rest of my garden? I heard that Sevin will not kill the beetles, but Malathion will. Is this true? (Dimock, S.D.)

A: Try a rotation crop in a different family, like carrots, beets, beans, or tomatoes. Squash beetles are difficult to control. That is why a variety of insecticides should be used. What you are likely experiencing is species resistance to Malathion - the insects are essentially using it as mouthwash. Sevin will work, along with Diazinon, Bioneem (organic approach), insecticidal soap (also organic), and if you really want to give them a dose they wont forget, use a spray composed of liquified garlic, onion, and habanaro (or jalapeno or cayenne) pepper. Your precaution: wear rubber gloves when preparing and applying. That pepper is hot! Liquify (or finely chop) one clove of garlic, one small onion, and one of the peppers (some use the powdered form). Mix it all with a quart of water, steep for at least an hour, strain thru cheesecloth, and add a tablespoon of liquid dish soap. Mix it well, and apply it when you see the dirty bounders! If they tolerate that, get a white flag and surrender!


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