Collard greens are the hardy, big-hearted leafy green of the southern garden: broad, smooth leaves that shrug off frost, shrug off heat better than most greens, and keep producing for months from a single planting. Braised with a little smoked meat, or simply wilted with garlic, they are one of the great comfort foods.
They take 60–80 days to mature and they are frost-tolerant, so they can be grown in spring and autumn, and in mild zones all winter. Pick the outer leaves and the plant keeps growing — a cut-and-come-again crop that feeds you for half the year.
Collard Greens at a glance
| Growing factor | What collard greens need |
|---|---|
| Sun | full sun |
| Soil pH | 6.0–7.5 |
| Days to germination | 7–10 |
| Days to maturity | 60–80 |
| Spacing | 12–18 inches |
| Water needs | moderate |
| Cold tolerance | frost-tolerant |
| Family | Brassicaceae |
Starting seeds
Collard Greens can be started indoors or sown direct, and either route works well. Indoors, sow in trays or cells and expect germination in 7–10 days; direct-sown seed goes into prepared soil once conditions are right for the crop. Starting indoors buys you a few weeks of season and gives steadier germination, while direct sowing is simpler and avoids transplant shock.
Choose the method that fits your season length: short-season gardens in Zones 3–5 gain the most from starting indoors, while Zones 8–10 can usually direct-sow with confidence. Our seed-starting calculator works out indoor sowing dates from your frost dates, and your local extension service can confirm what works in your area.
Collard greens can be started indoors or sown direct, with germination in 7–10 days. For a spring crop, sow indoors in late winter in Zones 3–6, or direct-sow in spring in Zones 7–9; for the main crop, sow in midsummer for autumn and winter harvest — in Zones 6–8 sow in late summer, in Zones 9–10 in autumn, and in frost-free Zones 11–13 sow in the cool season. Sow in trays or direct, thinning to the final spacing once seedlings have a few true leaves.
Transplanting and planting out
Set plants out 12–18 inches apart when they have four or five true leaves, in firm soil — collards, like all brassicas, prefer a firm bed. Water them in well and mulch to hold moisture. In hot zones, give young transplants a little shade for the first few days until they settle. Collards grow big, so do not crowd them: a cramped plant gives small, tough leaves.
When you set plants out, space them 12–18 inches apart — that spacing is what the mature plant needs, and crowding is one of the commonest causes of small harvests. Our plant-spacing calculator works out how many plants fit your bed, and the square-foot garden planner can lay the bed out for you. Harden seedlings off for a week before planting out, moving them outside for longer each day, and plant on a cloudy day or in the evening so they do not wilt in their first hours outdoors.
Soil and feeding
Collard greens want fertile, moisture-retentive soil at pH 6.0–7.5, with plenty of compost dug in before planting. They are hungry plants, so feed with a balanced fertiliser every few weeks through the season — nitrogen-rich feeding pushes the leafy growth you are growing them for. Like all brassicas, they should not follow another brassica in the same bed, so rotate them to fresh ground each year.
Aim for a soil pH of 6.0–7.5 — a simple soil test will tell you where you stand, and garden lime or sulfur can nudge pH up or down over a season. Feed lightly and steadily rather than in one heavy dose: too much fast nitrogen late in the season pushes leafy growth at the expense of the part you eat. Our fertiliser calculator works out amounts for your bed size, and the raised-bed soil calculator and soil-volume calculator tell you how much mix a new bed needs. A mulch layer after planting keeps the soil moist and cool and feeds the soil as it breaks down.
Watering
Water needs are moderate: keep the soil evenly moist through the growing season, watering deeply when the top inch or two dries out. Deep, infrequent watering builds deeper roots than a daily sprinkle, and it keeps the plants steady through dry spells.
Water needs are moderate, but collards must not dry out while they are growing fast — drought gives small, tough, bitter leaves. Water deeply in dry spells, especially in summer, and mulch to keep the moisture even. In winter, watering needs drop sharply, and in cold zones you may not need to water at all once the plants are established.
Water at the base of the plant, in the morning, so the leaves dry quickly and the water reaches the roots instead of evaporating off the surface. A soaker hose or drip line is ideal. Our watering calculator gives a starting point for your bed size and soil, and the watering schedule generator can build a routine around it. Mulch is your best friend here: a few inches of straw or shredded leaves cuts evaporation and keeps moisture even between waterings.
Sunlight and temperature
Collard greens need full sun for the best growth, though they tolerate light shade — a little afternoon shade in a hot summer keeps the leaves tender. They are frost-tolerant, and like most brassicas their flavour improves after a frost, which turns some of the starches to sugars. In Zones 8–10 they grow through winter easily; in Zones 3–5 a late-summer sowing gives an autumn crop that stands into early winter with a little protection.
This crop is rated frost-tolerant for cold tolerance, so plan your season around that: hardy and frost-tolerant crops can be sown and harvested around frosts, while tender crops need warm soil and frost-free nights. Our sunlight calculator can check whether your spot gets enough sun through the season, and the hardiness-zone finder will confirm your zone. If your summers run very hot, afternoon shade or a shade cloth can keep a cool-season crop productive for a few extra weeks.
Pests and diseases
Collards attract the usual brassica pests, and the big leaves give caterpillars plenty to eat. The ones to expect are cabbage worms, aphids, flea beetles and slugs.
- Cabbage Worms — green caterpillars that chew holes in leaves. Pick them off by hand and grow under fine mesh from planting day.
- Aphids — cluster on young leaves and in the growing point. Wash them off with water and encourage ladybirds.
- Flea Beetles — tiny beetles that pepper young leaves with shot-holes. Keep seedlings covered and watered — vigorous plants outgrow the damage.
- Slugs — chew leaves in wet weather. Pick them off at dusk and keep the base of the plant clear.
Inspect plants weekly, especially the undersides of leaves, and act early — a small problem caught in time is a hand-picked handful of pests, while a late one can cost the crop. Row cover keeps many flying pests off young plants, and healthy, well-watered plants resist attack far better than stressed ones. If you need help identifying what you are seeing, our pest-identifier helper and plant-disease checker walk through the symptoms.
Companion plants
Collard greens grow well with marigolds, basil, onions and lettuce. Marigolds and onions help confuse cabbage pests, lettuce fills the ground between young plants before the collards shade it out, and basil adds scent that masks the crop. As brassicas, collards should not follow another brassica in the same bed — rotate them, and do not plant them beside other brassicas.
Good companions for collard greens include:
- Marigolds
- Basil
- Onions
- Lettuce
Our companion-planting finder can suggest more pairings for your bed plan. As a general rule, avoid planting members of the same family (Brassicaceae) in the same spot year after year — rotate beds so soil-borne problems do not build up.
Harvesting
Start picking outer leaves once the plant is well grown, from about 60 days after sowing — snap the lowest leaves off at the stem, working your way up, and always leave the growing point intact. A plant picked this way keeps producing for months. For a whole-plant harvest, cut the head at the base. Leaves picked after a frost are sweeter than summer leaves, so the best collards come in autumn and winter.
Expect the crop to be ready about 60–80 days after sowing, though weather and variety shift that window by a week or two either way. Our harvest-date calculator works out your expected harvest date from your sowing date, and the vegetable-yield estimator can estimate how much a bed should produce. Harvest in the morning when plants are cool and crisp, and use a sharp knife or secateurs rather than tearing, which damages the plant and invites disease.
Common problems and fixes
| Problem | Likely cause | Fix |
|---|---|---|
| Tough, bitter leaves | drought or heat | Water deeply and mulch; pick after a frost. |
| Cabbage worms eating the leaves | butterflies laying eggs all summer | Grow under insect mesh from day one. |
| Bolting to seed | a hot spell or a cold snap | Sow for the cool season; keep plants watered. |
Tough, bitter leaves
Likely cause: drought or heat Tough leaves usually mean the plant went short of water or grew through hot weather. Keep the soil moist, mulch well, and pick young outer leaves — the best flavour comes after a frost.
Cabbage worms eating the leaves
Likely cause: butterflies laying eggs all summer White butterflies lay eggs on brassicas all summer, and the green caterpillars chew holes in the leaves. Fine mesh from planting day is the only reliable fix — check under the leaves weekly if you grow uncovered.
Bolting to seed
Likely cause: a hot spell or a cold snap Collards bolt when stressed by heat or by cold followed by warmth. Time your sowing for the cool season and keep the soil moist, and a bolted plant can still be eaten — the leaves just get tougher.
Frequently asked questions
When do I harvest collard greens?
Start picking outer leaves from about 60 days after sowing, once the plant is well grown. Leave the growing point intact and the plant keeps producing for months.
Do collard greens taste better after frost?
Yes — like most brassicas, frost turns some of their starches to sugars, so autumn and winter leaves are sweeter than summer ones.
How far apart do I plant collard greens?
12–18 inches apart. They grow big, with broad leaves, so don't crowd them — a cramped plant gives small, tough leaves.
Can I grow collard greens in summer?
Yes, better than most greens — collards handle heat well. But they still need steady water, and a little afternoon shade keeps the leaves tender.
Why are my collard leaves tough?
Usually drought or heat. Water deeply, mulch, and pick young outer leaves. The sweetest leaves come after a frost.