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 may result in tough, bitter kale leaves. None of the crops in this group thrive when daytime temperatures exceed 85°F.
Grow Guide Seed:
Kale may be direct seeded or transplanted. Direct-seed when outdoor temperatures are above 50°F (optimum 60–65°F). Plant seed ¼ inch deep, 6 seeds per row foot, allowing 18-24 inches between rows. As the plants grow, thin to one plant every 8-12 inches, eating the thinnings. 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 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 5–6 week old seedlings outside in a fertile garden bed 8-12 inches apart, allowing 18-24 inches between rows.
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 collards continuously a few leaves at a time starting at the bottom of the plant while the leaves are still young and healthy. Leave the newly forming leaves at the top to keep growing. The plant will eventually look like a tree with a bare stalk and leafy top. Store in the refrigerator to keep for about a week.