How to Grow Collard Greens

Growing guide

Overview

Collard greens are a loose-leaf brassica grown for their thick, nutrient-dense leaves. Gardeners value them because they tolerate frost and summer heat better than most cabbage-family crops and keep producing leaves for months. They need full sun, moderate moisture, and well-drained loamy or clay soil.

Soil & planting prep

Collards grow best in well-drained loamy or clay soil with a pH around 6.0 to 6.8. Work in 2 to 3 inches of compost before planting. Space plants 18 to 24 inches apart in rows 24 to 36 inches apart, and sow seeds 1/4 to 1/2 inch deep.

When to plant

Start seeds indoors 4 weeks before your average last spring frost date. Transplant seedlings or direct sow outdoors 2 to 4 weeks before the last frost, because collards tolerate frost and prefer cool weather. In USDA zones 8b to 11b, you can also sow in late summer to grow through winter.

How to plant

1. Start seeds indoors 4 weeks before the last frost by sowing them 1/4 to 1/2 inch deep in trays.
2. Harden off seedlings outdoors for 5 to 7 days before transplanting.
3. Transplant or direct sow outdoors 2 to 4 weeks before the last frost date.
4. Space plants 18 to 24 inches apart in rows 24 to 36 inches apart.
5. Water plants at the base after planting and spread mulch to keep soil evenly moist.

5 common mistakes to avoid

• Waiting until after the last frost to plant: collards tolerate cold and can bolt or turn bitter in early heat, so set them out 2 to 4 weeks before the last frost.
• Crowding plants: tight spacing reduces air movement and invites disease while producing small leaves, so thin or transplant to 18 to 24 inches apart.
• Ignoring cabbage worms and aphids: these pests strip and stunt collard leaves quickly, so check leaf undersides weekly and use row cover or BT for caterpillars.
• Letting lower leaves get oversized: old leaves turn tough and stringy, so harvest leaves when they reach about 8 to 10 inches long.
• Letting the soil dry out during warm spells: drought stress makes collard leaves tough and bitter, so water consistently and mulch the root zone.

Harvesting & storage

Begin picking lower leaves when they are about 8 to 10 inches long, usually around 60 to 80 days after seeding. Harvest from the bottom up, taking a few leaves per plant and leaving the central growing point. Store unwashed leaves in a plastic bag in the refrigerator for about a week.

Companion planting

Plant collards near onions, garlic, and dill to help deter common cabbage pests. Avoid grouping them with other brassicas such as cabbage, broccoli, and kale to reduce shared pest and disease pressure.

Growing in containers

Grow one collard plant in a 5-gallon container or grow bag with drainage holes. Use a quality potting mix and water more often than in-ground plants; place it in full sun.

Pro tips

Start indoors 4-6 weeks before last frost or direct sow. Harvest lower leaves as needed. Plants withstand hard frosts — flavor improves after cold snaps. In warm zones, grow as a fall/winter crop.