Even with the hot weather, it's time to start thinking about fall and cooler temperatures.
Some of my favorite vegetables are produced during the fall. These vegetables are cole crops and greens, and it is time to plant these vegetables in our gardens. These vegetables grow well in cool temperatures, but it is best to start them in mid-August to produce a crop in the fall. These vegetables are easy to grow and will produce for most of the winter.
The closely related vegetables commonly called cole crops include broccoli, cabbage, cauliflower, Brussels sprouts and kohlrabi. These vegetables can be grown in all types of soils, including sandy and clay soils. However, they do like soils that are well drained. If soils hold too much water, these vegetables can get root rot.
The soil pH needs to be 6.0 to 6.5, and this can be determined by having the soil tested. Cole crops require more fertilizer than most other vegetables. Some of the other heavy fertilizer users are tomatoes, Irish potatoes and sweet potatoes.
Cole crops can either be started from seeds or transplants. In our area, most gardeners use transplants, which saves two to three weeks' growing time. It is best to plant these vegetables over the course of several weeks. What I do is plant a third of my cole crops, wait a week to 10 days and plant another third, and wait a week to 10 days and plant the last third. This spreads the harvest over four to six weeks.
The time to plant is now until mid-September. I try to plant as soon as I find transplants at garden centers. Gardeners who grow their own transplants need to plant the seeds four to six weeks before time to transplant the plants to the garden.
Early planted cole crops can have some pest problems. The more common pest is the caterpillar. There are several different caterpillars that cause problems, including cabbage webworms, cabbage loopers, armyworms and corn earworms. They usually attack when the plants are small, and when the temperatures start to cool off they are not much of a problem.
A number of insecticides, including cararyl (Sevin), peremethrin, or esfenvalerate, can be used to control these pests. Make sure to read the label to see how long you have to wait before harvesting the vegetables. An organic control option is Bacillus thuringiensis (Dipel, Thuricide). This fungus attacks the caterpillars, and it works very well at controlling them.
Several diseases can attack these vegetables when the temperatures are hot, including Alternaria leafspot, downy mildew and powdery mildew. These diseases can be controlled by improving air circulation around the plants and keeping the leaves as dry as possible. If fungicides are needed, the copper fungicides or chlorothalonil (daconil) are the most effective.
Most of these vegetables, including broccoli and Brussels sprouts, will provide multiple harvests if they are left in the garden. Cabbage and cauliflower will yield only one harvest.
Greens, including collards, kale, spinach and mustard, also can be grown in the fall.
These vegetables are easy to grow and have a short growing season. Rapid growth is essential to producing the highest-quality vegetables possible. This rapid growth can be accomplished by fertilizing properly and thinning the crop.
Collards can be grown as transplants and planted in the garden. However, kale, spinach and mustards are planted from seed. When these seeds germinate, they will need to be thinned; otherwise, air movement will be reduced and more disease and insect problems will result.
Leaf spot diseases can be a problem early in the season. Fungicides containing copper work best for these disease problems.
Most insect problems can be controlled using insecticidal soaps.
Charles Phillips is a retired Columbia County Extension Service agent and operates Hort Consulting. He can be reached at firstname.lastname@example.org.
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