How to grow collard greens
Brassica oleracea (Viridis) · Brassicaceae · Vegetable
When to plant collard greens: the short answer
Start seeds indoors about 5 weeks before your last spring frost; plant out about 3 weeks before it; sow outdoors about 2 weeks before the last frost; for a fall crop, sow about 10 weeks before your first fall frost. Seeds germinate in soil from 45 to 85°F, fastest near 75°F.
Cold winters (zone 5): plant out Apr 2 – Apr 19, or sow Jul 17 – Aug 3 for a fall crop. Mild winters (zone 9): sow Sep 11 – Sep 28 for fall and winter harvests; the spring window (Jan 23 – Feb 9) closes before the summer heat. Skip the hottest months for collard greens. See every zone.
Collard Greens is a cool-season vegetable in the Brassicaceae family, grown either from a direct sowing or from transplants. It wants full sun, though it tolerates a little afternoon shade in hot regions and steady, even moisture. From sowing to first pick is about 55–75 days. It is one of the toughest crops here, standing through hard frost and often improving for it.
Grower’s note: The most heat- and cold-tolerant brassica - one spring planting can crop for months if you pick lower leaves and let it keep growing. Even sweeter after frost.
Sowing
Sow about 0.5″ deep, into soil between 45–85°F — germination is quickest near 75°F. It comes up fast (5–10 days). For an early crop, start seed indoors about 5 weeks before your last spring frost and grow it under bright light.
Spacing & layout
Give each plant about 18″ along the row with roughly 24″ between rows. On a square-foot grid that is 1 per square foot. Allow at least 18″ of loose, workable soil for the roots. It grows well in containers at least 12″ deep.
Fitting it to your season
As a cool-season crop, collard greens does its best growing in the mild weather of spring and fall and tends to bolt or turn bitter in summer heat. A second sowing in late summer, timed to mature as the weather cools, is usually the better crop of the year — and light frost only sweetens it.
Quick facts
Growth stages: how long collard greens takes to grow
From sowing to first harvest takes roughly 55-75 days (8-11 weeks), with seedlings appearing after 5-10 days in soil around 75°F.
When to plant collard greens
When to plant collard greens by USDA zone
Dates worked out from each zone’s typical frost dates for 2026. Find your zone on the zone map, or pick your state below for dates from its own frost dates. Zones 11 and above are frost-free, so timing there depends on heat and rain instead.
| Zone | Last / first frost | Start indoors | Sow or plant out | Fall or second sowing |
|---|---|---|---|---|
| Zone 3 | May 15 / Sep 15 | Apr 3 – Apr 17 | Apr 17 – May 4 | Jun 27 – Jul 14 |
| Zone 4 | May 10 / Sep 25 | Mar 29 – Apr 12 | Apr 12 – Apr 29 | Jul 7 – Jul 24 |
| Zone 5 | Apr 30 / Oct 5 | Mar 19 – Apr 2 | Apr 2 – Apr 19 | Jul 17 – Aug 3 |
| Zone 6 | Apr 15 / Oct 15 | Mar 4 – Mar 18 | Mar 18 – Apr 4 | Jul 27 – Aug 13 |
| Zone 7 | Apr 5 / Oct 25 | Feb 22 – Mar 8 | Mar 8 – Mar 25 | Aug 6 – Aug 23 |
| Zone 8 | Mar 20 / Nov 5 | Feb 6 – Feb 20 | Feb 20 – Mar 9 | Aug 17 – Sep 3 |
| Zone 9 | Feb 20 / Nov 30 | Jan 9 – Jan 23 | Jan 23 – Feb 9 | Sep 11 – Sep 28 |
| Zone 10 | Jan 30 / Dec 15 | Dec 19 – Jan 2 | Jan 2 – Jan 19 | Sep 26 – Oct 13 |
Companions
Onion, Dill, Potato, Beet
Tomato, Pole Bean, strawberry
Common problems
Pests: cabbage worm, cabbage aphid, cabbage looper, flea beetle.
Diseases & disorders: black rot, clubroot, downy mildew.
Same family (Brassicaceae)
Rotate these so they don’t follow each other in the same bed year to year.
Questions gardeners ask
When should I plant collard greens?
Start seeds indoors about 5 weeks before your last spring frost; plant out about 3 weeks before it; sow outdoors about 2 weeks before the last frost; for a fall crop, sow about 10 weeks before your first fall frost. Seeds germinate in soil from 45 to 85°F. The table on this page gives dates for each USDA zone, and the planting calendar gives dates for your own state or ZIP code.
How long does collard greens take to grow?
About 55-75 days from sowing to the first harvest. Seeds germinate in 5-10 days, fastest in soil around 75°F.
How much sun does collard greens need?
It needs six or more hours of sun for the best growth, though four to six hours in partial shade is enough.
What soil pH does collard greens need?
A soil pH between 6.0 and 7.5. Test before adding lime or sulfur - see the soil pH and testing guide.
How far apart should I plant collard greens?
Space plants about 18 inches apart in rows 24 inches apart, or 1 per square foot in a square-foot bed. Sow seeds about ½ inch deep.
Can I grow collard greens in a container?
Yes. Use a container at least 12 inches deep with drainage holes and a good potting mix, and water more often than you would in the ground.
Figures are typical home-garden ranges from Cooperative Extension planting guides, cross-checked against multiple state sources. Your variety and conditions will vary.