Q. What causes cabbage heads to be loose and puffy rather than firm and hard?
A. Some varieties of cabbage produce a looser, less dense head than others although this condition is generally associated with improper growing conditions. Cabbage grows best planted in time to head when daytime temperatures are under 80 degrees F. High fertility, improper water conditions and heat can cause loose, puffy heads.
Q. How can I prevent my cabbage heads from splitting when they are ready for harvest?
A. Cabbage head splitting can be avoided by keeping the soil uniformly moist near harvest time. Splitting can also be prevented by root pruning the plant about the time the heads mature. This can be done by cultivating near the plant or simply twisting the plant to break some of the roots. Splitting is seldom a problem with varieties maturing during cool weather.
Q. What causes my cabbage to send up a flower stalk?
A. Bolting, or flower of cabbage, is directly related to temperature. If the plants become dormant because of extended periods of cold weather, they will often go to seed, or bolt, when growth resumes. This condition can also occur if the temperature becomes too hot. Spring-planted cabbage is often seen flowering in gardens during mid-summer.
Q. I often have trouble in getting my cabbage to form a head. What is wrong?
A. Cabbage and all members of the cabbage family, such as cauliflower and broccoli, require cool temperatures, adequate moisture and high fertility to produce high yields of quality produce. Any condition which results in a stunting or stress on the plants during the growing period can result in some extent of crop failure.
Q. What is "Chinese cabbage" and how is it different from regular cabbage?
A. Chinese cabbage describes several greens which differ considerably. Like cabbage, they are cool season crops and bolt or go to seed in long days of late spring and summer. They grow best as a fall or early winter crop . Cultural practices are the same as for regular cabbage although Chinese cabbage matures quicker and may be ready in as few as 60 to 65 days from seeding. Chinese cabbage is used fresh in salads or cooked like regular cabbage.
Q. What is savoy cabbage?
A. Savoy cabbage is a crinkled or crumpled leaf variety. It is cultivated and harvested the same way as common types of cabbage.
Q. I have heard that cabbage plants will produce small secondary heads resembling Brussels sprouts. Is there any truth to this?
A. Small lateral heads may be harvested from early cabbage if the plants are left in the garden after the main head is removed. This is done by cutting carefully just beneath the solid head leaving the loose, older leaves uninjured. Sprinkle a small amount of fertilizer around each plant and water in. These small, Brussels sprout-like heads develop from buds located in the axils of older leaves. They should be harvested when of good size and firm. Their flavor, color and texture is excellent. Cabbage grows best under cool conditions and so do the secondary heads.
Q. What are "ornamental" cabbage and kale and are they edible?
A. Certain varieties of cabbage and kale produce decorative, non-heading plants with green or purple leaves and colorful white, cream, pink, red or purple interleaves. These are sold as flowering cabbage and can be used as attractive edging or for low accent plants in flower beds. Ornamental cabbage, like other members of the cole crop family, matures best under cool temperatures. The leaves are edible, but taste tough and strong. The plants are subject to the same insects and diseases as common cabbage.
Q. What causes the dark or black areas on the leaves inside cabbage heads?
A. You are describing internal tip burn. Although the cause is unknown, tip burn has been related to low soil moisture, high fertility and boron or calcium deficiency. To avoid this problem, maintain adequate fertility, especially during formation of the cabbage head and avoid excessive fertilization near maturity. Applications of a small amount of Twenty Mule Team Borax to the soil can compensate for boron deficiencies, but please remember excessive amounts can be toxic to plants. This treatment should be avoided until a boron deficiency is certain.
Q. As my cabbage approaches maturity, the head develops black, circular spots. These may be from the size of a penny up to the size of a half dollar.
A. This is Alternaria leaf spot and can be controlled with fungicide sprays.
Q. I recently harvested a head of cabbage that had black streaks throughout the stem and core area. This extended into the head, causing a foul-smelling decay.
A. This is black rot of cabbage and is caused by a seed-borne bacteria. The only control for this is use of resistant cabbage varieties. Cabbage which has been temporarily flooded is susceptible to this infection.
Q. The outer foliage of my cabbage plants develops a yellow lesion with downy growth underneath and is brittle.
A. This is downy mildew and can be controlled with chlorothalonil sprays beginning at the first sign of the disease. Repeat at 10 to 14 day intervals for two to three applications.
Q. What are the shield-shaped, brightly colored insects that seem to enjoy my cabbage more than I do?
A. No doubt you are describing harlequin bugs. This is one of the stinkbugs and can be a real problem on cabbage and related plants if left unchecked. At the first sign of problem with this insect, applications of most general-purpose insecticides result in satisfactory control. Always remove harvested or over mature cabbage, broccoli or cauliflower plants as these serve as excellent breeding and nesting places for harlequin bugs and as a good source of problems for next season's garden.
Q. What are these inch worms that are literally destroying my cabbage?
A. Although cabbage and related vegetable crops are bothered by many different types of worms, chances are you are describing cabbage loopers. Loopers, although a severe pest of cabbage, are relatively easy to control utilizing the biological insecticide Bacillus thuringiensis. This material gives excellent control of worms and can be used with complete safety around the home. It is sold under many trade names such as Biotrol, Thuricide, Dipel and Biological Worm Killer. Be sure to use 1 to 2 teaspoons of a liquid detergent per gallon of spray mixed to insure complete wetting of the waxy leaf surface.
Q. Occasionally my cabbage plants seem to be growing slowly and upon examining the roots, there are white webs and small crawling insects on the roots. Is this the cause of my problem and what can be done?
A. You are describing soil aphids. They can become a problem on members of the cabbage family and result in stunting, poor growth, low quality and poor yields of infested plants. This problem is relatively unpredictable and consequently control recommendations are generally not recommended. Applications of recommended soil insecticides such as diazinon generally give satisfactory control of soil aphids. Apply diazinon when the ground is being prepared and before seeding or transplanting.
Q. Occasionally some of my young cabbage plants become stunted and weak-looking, and upon inspection are covered by small, green bugs. What could be used to control these insects?
A. Aphids, called plant lice, are sometimes a real problem on cabbage and other members of this family. They are relatively easy to control utilizing insecticides such as malathion or diazinon, if applications are begun early before they become too numerous. Aphids reproduce rapidly which necessitates early control for satisfactory results.
Q. Could you please tell me how to control the green velvety worms that get in my cabbage?
A. Chances are these are imported cabbage worms, or perhaps head worms. Regardless of the type worm, satisfactory control can be obtained using a product containing Bacillus thuringiensis. This is a biological-type insecticide that gives excellent control for most types of worms. For this material to be effective, it must be eaten by the worm. Please note that it takes 2 to 3 days to be effective, which means that worm kill is not immediate. This is a completely safe chemical and can be used for controlling most types of worms on most commonly-grown garden vegetables. Use 1 to 2 teaspoons of a liquid detergent per gallon of spray mixed to insure adequate wetting of the waxy leaf surface.