🥦 Collard Greens
Brassica oleracea var. viridis
vegetables
brassica (leafy green, cole crop)
☀️ Sun
Full sun (6, 8 hours); tolerates partial shade well , one of the most shade-tolerant vegetables
💧 Water
Medium, high; 1, 1.5 inches per week; consistent moisture for tender leaves; drought stress causes tough, bitter leaves
🗺️ Zones
4, 5, 6, 7, 8, 9, 10
🧪 Soil pH
6.0, 7.5 (slightly acidic to slightly alkaline)
🪴 Soil Type
Rich, well-drained loam with high organic matter; collards are heavy feeders , incorporate 2, 3 inches of compost before planting; benefits from side-dressing with nitrogen mid-season
🚿 Drainage
Well-drained; tolerates heavier clay soils better than most brassicas; does not like waterlogged roots
📏 Spacing
12, 18 inches apart; rows 24, 36 inches; collards grow large (2, 3 feet tall/wide) , give ample space
⏱️ Maturity
55-75 days (from seed); baby leaves at 28-35 days
🍴 Edible Parts
🍽️ Leaves (main edible part , traditionally slow-cooked)
🍽️ Stems (chopped fine and cooked with leaves)
🍽️ Flower buds (collard raab , like broccoli raab, harvested before flowers open)
Key:🤝 Grows well together❌ Keep apart☀️ Sun needs💧 Water🗺️ Hardiness zone
🤝 Companions (7)
Improves brassica flavor; antifungal properties; attracts hoverflies and beneficial wasps
Attracts parasitic wasps that control cabbage loopers and diamondback moths; improves collard growth by deterring brassica pests
Excellent trap crop for aphids , cabbage aphids prefer nasturtium; repels cabbage worms IMPORTANT management caveat: without active management, nasturtiums can become a SOURCE of aphids that migrate to nearby crops. Either remove aphid-infested nasturtium plants promptly, or treat the trap crop itself to eliminate the aphid colony before it spreads. Strategic placement within 4-5 feet of protected crops is key.
Repels cabbage loopers and aphids; collards benefit from allium's pest-deterrent sulfur compounds
Some traditions plant collards near potatoes , collards may deter Colorado potato beetles; conflicting sources: potato may compete for nutrients
Aromatic oils mask brassica scent from cabbage moths; repels flea beetles
Repels cabbage moths, flea beetles, and carrot rust fly
⚠️ Keep Apart (4)
⚠️ Bean (pole/runner)
Beans and brassicas are traditionally separated , beans may be stunted by brassica root exudates
Allelopathic , severely inhibits collard growth
Brassicas and strawberries mutually inhibit growth; strawberries are susceptible to verticillium wilt which brassicas may harbor
Brassica root exudates may stunt tomato growth; separate by at least 3, 4 feet
💊 Medicinal Uses
Medicinal Properties
- Extremely nutrient-dense , excellent source of vitamin K (1 cup = 1000%+ daily value), vitamin A, vitamin C, and manganese
- Contains sulforaphane and indole-3-carbinol , powerful anti-cancer glucosinolates (especially against breast, colon, and prostate cancers)
- High in calcium (more bioavailable than spinach's calcium); also contains vitamin D2 (rare in vegetables)
- High fiber content , supports digestive health and cholesterol reduction
- Contains alpha-lipoic acid , antioxidant that may help lower blood glucose and improve insulin sensitivity
📝 Growing Notes
Collards are the most cold-hardy brassica alongside kale , flavor sweetens significantly after frost (starches convert to sugars). Can survive temperatures to 5°F (-15°C) with protection. Traditional Southern US staple , slow-cooked with smoked meat. 'Georgia Southern' is the classic variety; 'Champion' is more compact. Cut lower/outer leaves first for extended harvest (4, 6+ months per plant). Can be grown as a perennial cut-and-come-again crop in mild climates. Cabbage loopers are the main pest , Bt (Bacillus thuringiensis) or row covers for organic control.
🛒 Buy Seeds & Plants
Baker Creek Heirloom Seeds
Johnny's Selected Seeds
Botanical Interests
True Leaf Market
Burpee
Territorial Seed Company
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