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Some frequently asked questions about cabbage

By Melanie Mathieson
Gardening Guru

1. Cabbage seems to be susceptible to many diseases. Is this true?
Yellow or fusarium wilt is a relatively common disease that causes the leaves of plants to wilt and die. The first sign of the disease is yellowing and browning of the lower leaves. The plants are also stunted before wilting occurs. Fortunately science has resulted in modern hybrids that have tolerance or resistance to this disease bred into them. It is usually stated on the seed packet if the variety you choose is resistant to wilt.
Blackleg and black rot are two diseases that cause losses in cabbage crops. The plants may be stunted, turn yellow and die. Blackleg is named for the black cankers on the stem. The taproot often rots away. Black rot can be recognized by large, V-shaped, yellow-to-brown areas in the leaves, starting at the leaf edge. The veins turn black. Soft rot usually follows black-rot infection. Control is essentially the same for blackleg and black rot. Both diseases are spread by seed, transplants and insects. Buy seed that has been hot-water treated to kill the disease organisms (stated on package). Do not buy transplants that are wilted, are an unhealthy shade of green, or have black spots on the stems or leaves. Ask your nursery grower if they have used any preventative measures to prevent black rot before you buy your seedling.
Whenever you find diseased plants in the garden, collect the leaves, stems and tops and dispose of them in the garbage immediately. Do not put diseased plants into the compost pile. Avoid crowding, overwatering, planting in poorly drained soil and inadequate insect control which encourage the disease organisms of black rot and blackleg. If possible, grow black-rot-resistant varieties.
2. What can I do to prevent my cabbage heads from splitting?
Splitting is caused by the pressure of excessive water taken up after the heads are solid. Cutting the roots (spading on two sides of the plant) or breaking the roots (lifting and twisting the head to one side) can often reduce excessive splitting or bursting, but it also damages the plant and requires that the head be harvested relatively soon. Prevent heads from splitting by ensuring your garden receives even moisture and be careful around the bases of the plants when weeding and hilling with dirt.
3. What causes cabbage to develop seedstalks rather than solid heads?
Cabbage plants “bolt” (form premature seedstalks) when they are exposed to low temperatures (35 to 45 degrees Fahrenheit) for extended periods. Such chilling may happen if plants are set out too early or if an unseasonable blast of cold assaults the garden. If plants that have stems as large as a pencil are subject to cold conditioning a flowering response is initiated which forms a seedstalk.
4. What is flowering cabbage?
Non-heading varieties of cabbage (similar to flowering kale) have been developed for ornamental uses. They have colourful white, pink or red rosettes of leaves surrounded by green or purple outer leaves. Most colourful during cool fall weather, they should be started in early summer to midsummer and set out with fall and winter plantings of regular, heading varieties of cabbage. Flowering cabbage (and flowering kale) are edible as well as ornamental.
5. Why do butterflies fly around my cabbage plants?
Those butterflies (white or brown) are probably the moths of cabbage worms. They lay eggs on the plants. The eggs hatch into the worms that cause considerable damage unless controlled. Most control strategies are aimed at the developing larvae rather than the mature moths themselves.
6. What causes large, lumpy swellings of my cabbage roots? The plants also are stunted.
Swellings and distorted roots on stunted, wilted plants may be symptoms of clubroot disease. This disease is caused by a fungus that remains in the garden soils for many years once it becomes established. It is spread by movement of infested soil and infected transplants. Other related crops like broccoli and cauliflower also may become infected. If, in fact, you have clubroot in a location, destroy infected plant parts (including the roots) and for at least 4 years avoid planting any member of the cabbage family there, including radishes, turnips and ornamental relatives of cabbage.
7. I think of Cabbage as an odouriferous and unpleasant vegetable. Can anything be done about the smell when it is cooking?
Cooked cabbage has been wrongfully accused of smelling-up kitchens and homes. But don’t blame the cabbage, blame the cook. The notorious odour problem is a result of over cooking. Cabbage contains isothiocynates that break down into smelly sulphur compounds during cooking. The reaction is even stronger in aluminium pans. The longer the cabbage is cooked the more smelly the compounds become. The solution is a brief cooking time. Cook just until tender and use stainless steel pots and pans. On the other hand there is another adverse effect associated with cabbage - gas. Bacteria that live naturally in the intestinal tract degrade the dietary fibre (indigestible carbohydrates) in cabbage, producing gas that some find distressing. In spite of this unpopular side effect, cabbage offers huge benefits that cannot be ignored.