Cabbage Growiing Tips: Cabbage must be started indoors 6 weeks before your last frost date. You can direct sow a crop for fall harvest in mid - summer. Planting depth: 1/4 - 1/2". Plant early spring, early Summer or fall. Avoid planting cabbage in the same spot each year as with any cabbage family crop. Cabbage plants need up to 1 1/2 inches of water a week. Well - amended soil is vital to ensure vigorous growth. Cabbage is bothered by few insects and diseases. Floating row covers keep most insects at bay. Harvest cabbage heads when they have formed tight, firm heads. Cut the stem below the head but do not pull the remaining plant. Smaller cabbage heads often develop near the base of harvested heads. Days to maturity: 85 - 95 days, 6 - 12 days to germinate