When should I sow my cabbage seeds indoors?
Sow cabbage, broccoli, and cauliflower seeds indoors 4 to 5 weeks before the intended outdoor planting date. Cabbage, broccoli, and cauliflower seedlings can be planted outdoors in early April in southern Iowa, mid-April in central portions of the state, and late April in northern counties. Immediately after germination, place the seedlings under fluorescent lights in a cool (55 to 65 degree Fahrenheit) location. High light levels and cool temperatures will prevent the seedlings from getting tall and spindly. Harden (acclimate) the seedlings in a protected location for a few days prior to planting outdoors. Initially, place the seedlings in a shady location and gradually expose the plants to longer periods of sunlight.