Once cut, move it out of the sun as soon as possible. Store all harvested cabbage in the refrigerator. Cabbage can be stored at 32 F and 98 percent humidity for up to five months. Root-prune with spade or trowel or twist the stalk to break some of the roots and reduce water uptake. Common disease problems include black rot, wire stem, damping-off, downy mildew, Alternaria leaf spot and watery soft rot.
Cabbage is more susceptible to wire stem and downy mildew than Chinese cabbage.
Chinese cabbage is more susceptible to Alternaria. Black rot causes the most serious damage and appears as V-shaped lesions down the leaves and spreads into the water conducting system of the plant. Black rot is caused by a bacterium that is seed-borne or that can be transmitted by transplants. Warm, moist weather favors the disease. There is no control for black rot once it is established in a planting.