Varieties: cheddar, ruby ball, snow crown.  Plant in well drained soil.  Water at soil level avoiding the plant and keep consistently moist.  Drip system recommended.  Protect the heads from getting sunburnt by blanching (tying the outer leaves over the head) or plant self blanching variety.  Harvest when head forms into tight bunches about 6"" around.  Cut off plant right away when ready.  If allowed to form flowers it will be inedible.