Need help with problematic vegetables?
May 1, 2013
By Tiffany Woods
Too much water can cause cabbage heads to crack.
Are the vegetables in your garden so freakishly crooked that they need a chiropractor? Or maybe they're so immature that they would make a teenager look like a centenarian?
Jim Myers, a vegetable breeder at Oregon State University, might be able to diagnose your problem. He offers troubleshooting tips for growing carrots, cabbages and tomatoes – and he recommends how to grow them better next time.
Are your carrots more crooked than San Francisco's Lombard Street? They could be overcrowded. Next time, thin them to an inch apart after the leaves reach about three inches high. Did you plant them in clay soil? If you have heavy clay soil, it can force the roots to grow crooked. Amend clay soil in next year’s carrot patch with broken-down leaves and well-rotted compost. Carrots do well in sandy, fluffy soil that is not too full of amendments. You can also choose a type of carrot (such as French Forcing, Chantenay or Danvers) that produces shorter roots and is less prone to deformation.
Root-knot nematodes may also deform carrots. You can verify this with a soil test, and if it comes back positive for the nematodes, you might have to "solarize" the soil (treat it with the sun’s heat using plastic sheeting in the summer) to get rid of them. Or you can plant your carrots in another area next time.
If your carrots are coming out hairy it may have to do with your fertilizer. Excess nitrogen from over-fertilizing can cause carrots to form multiple roots or grow "hair." If you add manure-laden compost to your soil, do so in the fall, then let it overwinter before planting carrots in the spring. Carrot roots will also become hairy in waterlogged ground.
Did you leave your carrots in the ground too long? Carrots are biennials. In the first year, they grow a taproot. The second year, they put out secondary roots off of it and send up a flowering stem. If you planted your carrots last fall, then overwintered them in the ground, they might be sending out whitish secondary roots by now and maybe a stem. Some varieties are more prone to bolting than others.
Are your cabbage heads cracking? Perhaps you're watering too much. Excess irrigation after a period of little or no watering can cause the heads to swell until they crack. Cabbages also crack when they're mature. Try watering them less and harvesting them earlier.
Or maybe your heads aren't developing properly? Hot weather can cause them to be stunted or misshapen. Adequate watering may overcome this. It's better to water deeply with longer intervals between watering than to water frequently but shallowly. Poor heading can also be caused by overcrowding your cabbage. Thin your plants early in the season to at least 18 inches apart.
Disease may also stunt growth. Pull up one of your stunted plants and examine the roots. Do they look clubby with large swellings? You may have club root fungal infection. If so, don’t plant any of the brassica family in that spot again for seven years. Root rot is another infection that thrives in clay soil. It can kill much of a plant’s root system. If you have it, plant something else in this area of your garden.
Are your blossoms falling off? It could be the aptly named blossom drop. It's usually caused by dry soil and dry winds but also may be caused by a sudden cold spell, heavy rain or too much nitrogen. Usually not all blossoms will fall off, so just be patient for the next set of flowers.
Are the ends of the fruit farthest from the stem turning black? It might be blossom end rot. It's most common in western Oregon, and it's caused by irregular watering and calcium deficiency. Water deeply and regularly. Add lime to soil in the fall to increase the calcium in the soil for next year’s crop.
Are the edges of your leaves curling up? This could be leaf roll. It's most often the result of heavy pruning or root injury. Plants may lose leaves but will recover. Some varieties have a genetic trait that causes leaf roll under stressful conditions like cold, heat and drought. Plants with this trait will produce normally despite their appearance.
Do your leaves have purplish black lesions with maybe a cottony white mold along the edges of the lesions? It could be late blight. Look for spots that appear water-soaked on lower leaves and stems. If you see these, pick them off. Avoid overhead watering, and remove diseased leaves. Avoid prolonged leaf wetness from overhead irrigation or heavy dews.
For photos and more information on vegetables with various diseases, check out the Pacific Northwest Plant Disease Management Handbook. In the search box, type in the vegetable you want to know about.
You can call or visit the Master Gardener help desk at the OSU Extension Service's office in your county. Head over to our Ask a Master Gardener website for more information.
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