The common vegetables related to cabbage are collectively called the cole crops. Cole crops grow best in temperatures between 60 and 70 degrees F. Cabbage and broccoli are the easiest to grow and should be planted from transplants in early spring.   In central Iowa, plant broccoli, cabbage, and cauliflower in mid-April.  MOREHarvest cole crops at the peak of maturity for best quality.   MORE See also ISU Extension pamphlet PM1896, "Cole Crops" available on the Internet from the ISU Extension Online Store.