T The most successful technique for how to harvest cabbage is cutting. Cut at the lowest point possible, leaving the loose outer leaves attached to the stalk. This will allow for a later cabbage harvest of sprouts which will grow on the stem after the cabbage head is removed. Knowing when to pick cabbage is particularly important if rain is expected. Mature heads may be split by excessive rainfall or over watering, making them inedible. Harvesting cabbage should happen before the rainfall has a chance to damage the cabbage heads.