Get an early crop started by setting out seedlings 2-3 weeks before the last expected frost. Space seedlings about 2-3 feet apart. A second crop can be planted in July. Even watering is the key to preventing cabbages from splitting.
Cabbage worms are the main pest threat. They don’t do a great deal of damage and can be hand picked easily, if you can see them. Their coloring allows them t blend in with the cabbage.
Source: Cabbage - Growing and Caring for Cabbage in the Vegetable Garden
Harvest when the head forms and they are firm to the touch. Leave the wide, outer leaves and just cut the head. Cabbages can be stored for months in a root cellar where the temperature is between 45 degrees F. and freezing.
Photo by: La Grande Farmer's Market