Play It Cool With Cole Crops (Cabbage, Etc.); They Attain Best Quality If Matured in Fall

by Philip A. Minges.

Philip A. Minges is Professor of Vegetable Crops, Cornell University, Ithaca, N.Y.

The closely related vegetables commonly referred to as cote crops include cabbage, cauliflower, brussels sprouts, broccoli, and kohlrabi. Being frost-tolerant, they are valuable for extending the harvest season for gardens after frost or cool weather has eliminated the popular warm season vegetables.

In fact, this group of vegetables develops best quality and remains edible longer in the garden when matured during the moderately cool weather and shorter days of fall. When maturing in hot weather, the harvest period is relatively short, quality often is less desirable, and yields are likely to be lower.

The crops are adapted to all sections of the United States provided proper planting dates are selected. In areas with short growing seasons, spring plantings for summer and early fall harvest work well. In intermediate areas, early spring plantings for summer harvest are possible while summer plantings for fall harvest are ideal. In areas with mild winters, late summer or early fall plantings for fall and winter harvest are common.

For broccoli, cabbage and cauliflower, planting two or more varieties of differing maturities for example, a fast and a slow maturing one can easily extend the harvest season from a single planting from a week or so to a month or more.

Local information on varieties and preferred planting dates should be sought by gardeners. Poor selection of varieties and/or planting dates may lead to poor results due to premature seeding caused by undue exposure to cool temperatures early in the growing season and other problems.

As a group these vegetables rank fairly high in nutritional value and are quite adaptable for use fresh or cooked and for preserving. Cauliflower is suitable for freezing, canning or pickling. Broccoli and brussels sprouts are excellent for freezing. Cabbage when kept cool and moist will store for several weeks after harvest and, of course, it can be preserved as sauerkraut.

Cole crops can be grown on a wide range of soils. Fertile, deep, well-drained, sandy and silt looms are the most desirable. Have a soil test made; your county Extension office can tell you how to have this done. Good drainage is particularly important where the garden will be continued into or through the winter months.

A soil pH level of around 6.5 or slightly above is desirable for efficient use of fertilizer and soil nutrients, and for reducing development of a soil-borne disease called club-root. If the soil is acid as indicated by a pH reading below 6.0, apply lime before preparing the garden. In humid areas with acid soils, apply it at a rate of 10 pounds per 100 square feet every 3 to 5 years. This should maintain a good soil pH once the pH has been brought up to the desirable level.

In some parts of the Eastern United States and generally in the Western portions, soils tend to be alkaline and therefore don't require lime. In many desert areas a problem may be excessively high pH and/or a high salt content. Avoid highly saline soils if possible, or correct them by leaching perhaps in combination with the addition of sulfur. There are a few exceptions, but minor element problems seldom are serious when the pH level is in the range of 6.0 to 7.5.

Fertile soils may supply sufficient amounts of nitrogen, phosphorus and potassium for cole crop needs, making fertilizer applications unnecessary. In the Western States nitrogen is often the only limiting nutrient, though phosphorus applications may benefit late fall and winter plantings.

In the humid Eastern States a complete fertilizer usually is advisable. On new garden sites or where fertility is known to be low, 3 to 4 pounds per 100 square feet of a 5-10-10 fertilizer is advised. On more fertile soils 1 to 1 1/2 pounds may be adequate. A side-dressing with nitrogen at a rate of about a half pound of ammonium nitrate per 20 feet of row, applied 2 to 4 weeks after planting, may be beneficial on sandy soils, when heavy rains occurred shortly after planting, or during relatively cool weather.

Planting and Culture

Cole crops can be established in the garden either by setting transplants or by seeding. Using transplants is the rule for cabbage, broccoli, cauliflower and brussels sprouts in many areas while kohlrabi normally is seeded. Using transplants saves 2 to 3 weeks growing time in the garden. But for fall crops of cabbage, broccoli and cauliflower, direct seeding with later thinning is very satisfactory. To obtain similar maturity, seeding should be done about 2 weeks earlier than setting transplants.

A desirable transplant is 4 to 5 weeks old with 3 to 5 true leaves, and is free of diseases. Older transplants sometimes will head a bit earlier but otherwise there is little advantage; in fact, head sizes often average considerably smaller when old, larger plants are set out. You can buy transplants at local garden supply outlets, or grow them at home. In direct seedings, the plants being thinned can serve as transplants if carefully dug. When reset immediately, they will reach harvest stage some 10 to 14 days later than the undisturbed plants thus spreading the harvest period from a single seeding.

Transplants to be used for early spring planting should be grown at temperatures no lower than 60 F to lessen the hazard of premature flower stalk formation.

Either flat or bed culture is suitable. Beds have an advantage when soil drainage is likely to be slow during the late fall and winter months, and where furrow irrigation is practiced. In the Western States, beds about 6 to 8 inches high and 30 to 42 inches center to center are common. On the wider beds, 2 rows 12 to 14 inches apart can be used for most of these crops except brussels sprouts, for which 1 row is usual. Fertilizer can be broadcast before forming the beds or banded later along the sides. Forming the beds a few days ahead of planting to allow the soil to settle a bit is a good practice when time permits.

In transplanting, dig holes deep enough to accommodate the root system (or soil block), place the plant in the hole, and then firm some soil around the roots or soil block. Often it helps to apply a cup of starter solution containing some soluble fertilizer, and in areas where root maggot is troublesome a chemical for control of this pest.

After the water has drained down, pile more soil around the plant so the stem is covered a bit higher than it was in the plant-growing container.

In direct seeding, open shallow furrows and drop seeds about 1 inch apart. Partially cover the seed with soil and firm it over the seed, then finish covering with loose soil to a total of 1/2 to 1 inch in depth. If the soil is dry and rains are not expected, water immediately. In hot, dry weather, you may need to sprinkle or otherwise apply water a few times to insure adequate germination. When the plants show 2 to 3 true leaves, thin them to the desired spacings.

A row spacing of 30 to 36 inches is suitable. Slightly closer rows will do when space is limited, especially for kohlrabi. Common spacings in the row are 15 to 24 inches for cabbage, cauliflower, and broccoli; 30 to 36 inches for brussels sprouts; and 4 to 6 inches for kohlrabi.

You can control weeds easiest when they are small, using a hoe or small hand cultivator. Approved herbicides can be applied before planting and worked into the soil when rather large plantings are contemplated. Consult the label for rates and other instructions. Weedy gardens are never as productive as those kept weed-free.

All cole crops develop most rapidly and with best quality when adequate soil moisture is provided throughout the season. In humid areas, irrigation during dry periods can be helpful. In areas with normally dry summers, irrigation is essential until fall and winter rains begin. Light irrigation should start at transplanting or seeding and the amount gradually increased as the plants grow until about 1 to 1 1/2 inches of water is applied weekly.