Kale and Collards
Kale and collards, a type of kale, share the same species, Brassica oleracea, and are considered non-heading or loose-leaf members of the cabbage family. Both grow best in the cool season, sweetened by frost. Although they may also be grown in summer, high temperatures and strong sun may lead to bitter tastes. Both vegetables are highly nutritious, but kale is reputed to have more vitamins and minerals than any other garden vegetable. Both are biennials that send up flower/seed stalks the second year.
- Select from a varied group of cultivars: tall, short, dwarf, curly, straight, blue-green, yellow-green, or red. ‘Lacinato’ is tall, blue-green with crinkly leaves.
- Sow Russian-Serbian types directly in garden beds; they do not transplant easily. These are considered the most tender and mild-flavored.
- Prepare beds in rich soil amended with compost. Rotate crops to avoid planting cabbage family plants in the same space year after year.
- Plant March-November for optimal harvest when temperatures are cool for sweetest flavor. Summer crops are more successful near the coast rather than in hot inland areas.
- Start seed in place in full sun for best germination or in pots to transplant. Thin to 12-18 in. in rows 18 in. apart. Keep soil evenly moist.
- Harvest young leaves in 30 days for use raw in salads; older leaves in 60-70 days, removing lowest ones when they are 5-8 in. long.
- Watch for the same pests that frequent broccoli and cabbage: aphids, looper worms, earwigs. Handpick or spray with a jet of water from a hose to dislodge aphids. Use a spun fabric row cover after planting to exclude pests.
- Plant ornamental types for winter color in any garden setting.
Growing Collard Greens
- Rotate planting beds to avoid planting cabbage family crops in the same space year after year.
- Choose tall or short varieties. ‘Champion’ is short-stemmed with waxy blue-green leaves bred for extended harvest. ‘Georgia’ has a larger habit. ‘Merritt’ is a hybrid closely related to kale, 4-6 ft. tall and is said to be very drought tolerant.
- Sow seeds in full sun March-November in fertile, well-drained soil.
- Thin to 1-3 ft. apart in rows 3 ft. apart, allowing for large, spreading leaves.
- Harvest young, tender leaves in 60-75 days after planting.
- Do not pick large lower leaves as plants mature; they nurture the entire plant as new leaves grow, many on stems 2-3 ft. tall.
- Irrigate in the absence of rain for consistently moist soil.
- Watch for the same pests that frequent kale, broccoli, and cabbage: aphids, looper worms, earwigs. Handpick or spray with a jet of water from a hose. Use a spun fabric row cover after planting to exclude pests.
- Sonoma County Master Gardener Vegetable Planting Summary.