Cabbage - Care
Use starter fertilizer when transplanting and side-dress with nitrogen fertilizer when the plants are half grown. Cultivate shallowly to keep down weeds. Ample soil moisture is necessary throughout the growing season to produce good cabbage. Irrigation is especially important in fall plantings to help the young plants withstand the intense sunlight and heat of summer and to supply the developing heads with sufficient water to develop quickly.
Cabbage can be harvested anytime after the heads form. For highest yield, cut the cabbage heads when they are solid (firm to hand pressure) but before they crack or split. When heads are mature, a sudden heavy rain may cause heads to crack or split wide open. The exposed internal tissue soon becomes unusable. Harvest and salvage split heads as soon as possible after they are discovered.
In addition to harvesting the mature heads of the cabbage planted in the spring, you can harvest a later crop of small heads (cabbage sprouts). These sprouts develop on the stumps of the cut stems. Cut as close to the lower surface of the head as possible, leaving the loose outer leaves intact. Buds that grow in the axils of these leaves (the angle between the base of the leaf and the stem above it) later form sprouts. The sprouts develop to 2 to 4 inches in diameter and should be picked when firm. Continue control of cabbage worms and other pests. If this control cannot be maintained, remove and destroy or compost the stumps, because they serve as a breeding ground for diseases and insect pests.
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 stunted before wilting occurs. Grow yellows-resistant (YR) or yellows-tolerant varieties. Most modern hybrids have this tolerance or resistance bred into them.
Blackleg and black rot are two diseases that cause severe losses. 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. Do not buy transplants that are wilted, are an unhealthy shade of green, or have black spots on the stems or leaves.
When you find diseased plants in the garden, collect the leaves, stems and tops; and burn or dispose of them. Do not put diseased plants into the compost pile. Avoid cultural practices (crowding, overwatering, planting in poorly drained soil and inadequate insect control) that support the disease organisms of black rot and blackleg. If possible, grow black-rot-resistant varieties.