Cabbage
Q. What causes cabbage heads to be loose and puffy rather than firm andhard?
A. Some varieties of cabbage produce a looser, less dense head than othersalthough this condition is generally associated with improper growingconditions. Cabbage grows best planted in time to head when daytimetemperatures are under 80 degrees F. High fertility, improper water conditionsand heat can cause loose, puffy heads.
Q. How can I prevent my cabbage heads from splitting when they are ready forharvest?
A. Cabbage head splitting can be avoided by keeping the soil uniformly moistnear harvest time. Splitting can also be prevented by root pruning the plantabout the time the heads mature. This can be done by cultivating near theplant or simply twisting the plant to break some of the roots. Splitting isseldom 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. Ifthe plants become dormant because of extended periods of cold weather, theywill often go to seed, or bolt, when growth resumes. This condition can alsooccur if the temperature becomes too hot. Spring-planted cabbage is often seenflowering in gardens during mid-summer.
Q. I often have trouble in getting my cabbage to form a head. What iswrong?
A. Cabbage and all members of the cabbage family, such as cauliflower andbroccoli, require cool temperatures, adequate moisture and high fertility toproduce high yields of quality produce. Any condition which results in astunting or stress on the plants during the growing period can result in someextent 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. Likecabbage, they are cool season crops and bolt or go to seed in long days of latespring and summer. They grow best as a fall or early winter crop . Culturalpractices are the same as for regular cabbage although Chinese cabbage maturesquicker and may be ready in as few as 60 to 65 days from seeding. Chinesecabbage 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 andharvested the same way as common types of cabbage.
Q. I have heard that cabbage plants will produce small secondary headsresembling Brussels sprouts. Is there any truth to this?
A. Small lateral heads may be harvested from early cabbage if the plants areleft in the garden after the main head is removed. This is done by cuttingcarefully just beneath the solid head leaving the loose, older leavesuninjured. Sprinkle a small amount of fertilizer around each plant and waterin. These small, Brussels sprout-like heads develop from buds located in theaxils of older leaves. They should be harvested when of good size and firm.Their flavor, color and texture is excellent. Cabbage grows best under coolconditions 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-headingplants with green or purple leaves and colorful white, cream, pink, red orpurple interleaves. These are sold as flowering cabbage and can be used asattractive edging or for low accent plants in flower beds. Ornamental cabbage,like other members of the cole crop family, matures best under cooltemperatures. The leaves are edible, but taste tough and strong. The plantsare 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, tipburn has been related to low soil moisture, high fertility and boron or calciumdeficiency. To avoid this problem, maintain adequate fertility, especiallyduring formation of the cabbage head and avoid excessive fertilization nearmaturity. Applications of a small amount of Twenty Mule Team Borax to the soilcan compensate for boron deficiencies, but please remember excessive amountscan be toxic to plants. This treatment should be avoided until a borondeficiency 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 throughoutthe stem and core area. This extended into the head, causing a foul-smellingdecay.
A. This is black rot of cabbage and is caused by a seed-borne bacteria. Theonly control for this is use of resistant cabbage varieties. Cabbage whichhas been temporarily flooded is susceptible to this infection.
Q. The outer foliage of my cabbage plants develops a yellow lesion with downygrowth underneath and is brittle.
A. This is downy mildew and can be controlled with chlorothalonil spraysbeginning at the first sign of the disease. Repeat at 10 to 14 day intervalsfor two to three applications.
Q. What are the shield-shaped, brightly colored insects that seem to enjoy mycabbage more than I do?
A. No doubt you are describing harlequin bugs. This is one of the stinkbugsand can be a real problem on cabbage and related plants if left unchecked. Atthe first sign of problem with this insect, applications of mostgeneral-purpose insecticides result in satisfactory control. Always removeharvested or over mature cabbage, broccoli or cauliflower plants as these serveas excellent breeding and nesting places for harlequin bugs and as a goodsource 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 differenttypes of worms, chances are you are describing cabbage loopers. Loopers,although a severe pest of cabbage, are relatively easy to control utilizing thebiological insecticide Bacillus thuringiensis. This material givesexcellent control of worms and can be used with complete safety around thehome. It is sold under many trade names such as Biotrol, Thuricide, Dipel andBiological Worm Killer. Be sure to use 1 to 2 teaspoons of a liquid detergentper gallon of spray mixed to insure complete wetting of the waxy leafsurface.
Q. Occasionally my cabbage plants seem to be growing slowly and upon examiningthe roots, there are white webs and small crawling insects on the roots. Isthis the cause of my problem and what can be done?
A. You are describing soil aphids. They can become a problem on members ofthe cabbage family and result in stunting, poor growth, low quality and pooryields of infested plants. This problem is relatively unpredictable andconsequently control recommendations are generally not recommended.Applications of recommended soil insecticides such as diazinon generally givesatisfactory control of soil aphids. Apply diazinon when the ground is beingprepared and before seeding or transplanting.
Q. Occasionally some of my young cabbage plants become stunted andweak-looking, and upon inspection are covered by small, green bugs. What couldbe used to control these insects?
A. Aphids, called plant lice, are sometimes a real problem on cabbage andother members of this family. They are relatively easy to control utilizinginsecticides such as malathion or diazinon, if applications are begun earlybefore they become too numerous. Aphids reproduce rapidly which necessitatesearly control for satisfactory results.
Q. Could you please tell me how to control the green velvety worms that get inmy cabbage?
A. Chances are these are imported cabbage worms, or perhaps head worms.Regardless of the type worm, satisfactory control can be obtained using aproduct containing Bacillus thuringiensis. This is a biological-typeinsecticide that gives excellent control for most types of worms. For thismaterial to be effective, it must be eaten by the worm. Please note that ittakes 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 typesof worms on most commonly-grown garden vegetables. Use 1 to 2 teaspoons of aliquid detergent per gallon of spray mixed to insure adequate wetting of thewaxy leaf surface.
