Grow Guide Conditions:
Broccoli, Brussels sprouts, Cabbage, Cauliflower, Collards, Kale, and Kohlrabi are all closely related members the Brassica genus. All of these crops are relatively cold hardy and perform best in cool, moderate climates with consistent moisture and a soil pH of 6.0–7.2. Excessively high temperatures for broccoli and cauliflower may result in premature head formation, the presence of leaves in heads, or development of loose heads. None of the crops in this group thrive when daytime temperatures exceed 85°F. Of all the brassica crops, Cauliflower is the most difficult to grow and must be pampered for success.
Grow Guide Seed:
Cauliflower is best started indoors and transplanted. Start spring crops 6 weeks before the last frost date, and transplant out 2-3 weeks before the last frost date. Start fall crops 12 weeks before the first fall frost and transplant out 9 weeks before the first frost. To start seedlings indoors, fill starter trays with a sterile seed starting mix. Plant 2 seeds per cell, ¼ inch deep. Ideal soil temperature for germination is 65-75°F. Thin to 1 plant per cell. Maintain greenhouse temperatures above 45°F night and below 85°F day. Harden-off seedlings for 5–7 days prior to transplanting. Transplant 3-4 week old seedlings outside in a fertile garden bed 12-18 inches apart, allowing 18-24 inches between rows. Be careful not to disturb the roots when transplanting. Direct-seed when outdoor temperatures are above 50°F (optimum 60–65°F). Plant seed ¼ inch deep, grouping 3-4 seeds every 18-24 inches, allowing 18-24 inches between rows. Thin to one plant in each spot.
Grow Guide Pests:
Practice 2–4 year crop rotations between all Brassicaceae species. Insect pressure on fall-harvested brassicas is typically not as heavy as on spring crops. Encourage beneficial insect activity for suppression of aphids, and/or control aphid outbreaks with insecticidal soap. Control cabbage worms and loopers with Bt (Bacillus thuringienthus), available commercially as Dipel. Floating row covers used from the day of planting will protect from heavy flea beetle damage on spring crops. Maintain a pH between 7.0-7.2 for suppression of Club Root (Plasmodiophora brassicae). See our merchandise section for related products.
Grow Guide Harvest:
Harvest cauliflower when the heads are 6-8 inches across and the curds are still tightly closed. Heads will keep several weeks in the refrigerator. Cauliflower freezes well.