How to Grow Collards: Planting, Spacing, Care & Harvest

Quick answer

Spring: plant about 4–6 weeks before last frost (Purdue). Fall: Purdue at least 4–8 weeks before first frost; UMN about three months before average frost for a direct-seed fall crop. Seed ¼–½ inch deep; thin/set about 8–12 inches (UMN) or 6–18 inches (Clemson). Steady moisture and cool weather keep leaves tender.

Collards at a glance

Plant6–4 wk before last frost; Fall plant (Purdue): 8–4 wk before last frost; Fall direct sow (UMN): 13–12 wk before last frost
WaterUMN: loamy, well-drained, high organic matter; pH 6.0–7.5; about 1 inch water/week; heat or moisture stress → pungent/bitter leaves; mulch 3–4 inches; rotate off cole crops 4 years.
SpacingClemson: rows 18–36 inches; plants 6–18 inches on the row; direct seed ¼–½ inch deep (deeper than ½ inch likely will not germinate); thin at three-leaf stage.
Days to harvest60–70 days (Clemson planning); 60–80 days after direct seeding (Clemson collards factsheet)
-14-13-12-11-10-9-8-7-6-5-4-3-2-1LF+1+2+3
■ Start indoors   ■ Plant out   ■ Harvest
Weeks relative to last frost (LF). Colored weeks show when our ZIP planner schedules each step.
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Updated

Planting dates for your ZIP: the ZIP planting planner counts each window from your local frost dates.

Organic pests and diseases: see also organic pest control. Use any product as the label directs.

Leafy Acephala group (Brassica oleracea), same group as kale — not Russian/Siberian kale (B. napus). Shared pests: organic kale and organic cabbage.

Collard green leaves
Collard leaves. Photo: USDA ARS (Ann Perry), Wikimedia Commons, Public domain (resized).

Planting timing

Purdue HO-186: hardy cool-season — plant 4–6 weeks before last spring frost. Fall Table 2: cool-season plants for late-summer/fall planting at least 4–8 weeks before first fall frost; collards listed (Purdue HO-186). UMN: direct seed or start indoors in April for early summer; for fall crops start seed indoors in June; direct seed spring as soon as soil is workable; direct seed again about three months before the average frost date for fall. Cold-tolerant; continues past first fall frosts (UMN Extension). Clemson: preferred early spring or fall; transplants preferred in spring; start seeds indoors six to eight weeks before desired planting; direct seed late summer for fall when soil is warmer (Clemson HGIC). Present spring and fall paths with sources labeled.

Depth and spacing

Clemson: rows 18–36 inches; plants 6–18 inches on the row; direct seed ¼–½ inch deep (deeper than ½ inch likely will not germinate); thin at three-leaf stage. UMN: seed ¼–½ inch deep; rows 18–30 inches; thin to 8–12 inches; transplants 8 inches apart in 18-inch rows; baby-leaf as close as 4 inches. Sources differ on in-row spacing — show each.

Sun, soil and water

UMN: loamy, well-drained, high organic matter; pH 6.0–7.5; about 1 inch water/week; heat or moisture stress → pungent/bitter leaves; mulch 3–4 inches; rotate off cole crops 4 years. Clemson: many soils OK; maintain pH 6.0–6.5; uniform moisture; water early so leaves dry before night; wet soil at least 6 inches deep. Fertility: soil test; with manure or compost you may not need additional fertilizer (UMN). No synthetic product rates.

Harvest and storage

Days: Clemson planning shorthand 60–70; Clemson collards factsheet 60–80 days after direct seeding (cultivar-dependent); microgreens 10–15 days. Clemson: cut whole plants half- or full-grown, or pick individual leaves from the bottom up; fridge in plastic bag up to 2 weeks. UMN: harvest single leaves at usable size for multiple cuts, or cut whole plant at soil line; traditional to eat through cold season; freezing for surplus. Spring: harvest before hot dry weather toughens leaves; fall cool weather improves flavor (UMN).

Pests and diseases (organic)

Cole caterpillars, flea beetles, cabbage maggots, harlequin bugs, aphids (Clemson; UMN). Cultural: row cover from planting; handpick; destroy residue; remove brassica weeds; Btk/spinosad while caterpillars are small — follow the label (UMN). Harlequin bug: row cover; crush; soap/neem on nymphs (UMD). Diseases: black rot, downy mildew, Alternaria, Fusarium yellows (summer; Clemson); clubroot (UMN) — 4-year rotation off cole crops; sanitation; avoid chronic leaf wetness. See organic kale and cabbage-family companions.

Related: ZIP planner · cabbage-family companions · organic kale · organic cabbage · organic pest control

Frequently asked questions

When do I plant collards?

Spring: about 4–6 weeks before last frost (Purdue). Fall: Purdue at least 4–8 weeks before first frost; UMN about three months before average frost for a direct-seed fall crop, or June indoor starts in cold climates. Clemson favors early spring and fall in the Southeast.

How far apart?

Thin/set about 8–12 inches (UMN) or 6–18 inches (Clemson); rows roughly 18–36 inches. Closer spacing for baby leaves (UMN 4 inches).

How do I keep leaves from tasting bitter?

Steady moisture and avoid heat stress (UMN). Fall cool weather improves flavor.

More grow guides: Carrots · Strawberries · Shallots · Raspberries · Spinach · Sweet Corn · Beets · Dill · Bok Choy · Brussels Sprouts · All grow guides

Sources