Growing collard greens in USDA Zone 9 means gardening in one of the warmest zones in the country: average winter lows of 20 to 30°F, an average last spring frost of Jan 30–Feb 15 and an average first autumn frost of Dec 1–15, giving a frost-free window of roughly 290–320 days. Frost dates vary by microclimate, elevation and year — check your local extension service.
Collard greens are one of the great Zone 9 winter vegetables. They are frost-tolerant, they actually taste better after a touch of cold, and they produce steadily through the mild Zone 9 winter when warm-season crops are long finished. In fact Zone 9 is one of the best places in the country to grow collards: while northern gardeners get a short autumn window, Zone 9 gardeners can harvest collards from autumn right through to spring.
When to plant collard greens in Zone 9
In Zone 9, start indoors in August to September for autumn transplanting, or direct sow September to October and transplant out September to October for autumn crops; January to February for a spring crop.
The table below puts the whole season on one page, worked back from the Zone 9 frost averages and the crop's published days to maturity (60–80 days). Use the frost date calculator to check the averages for your own area.
| Stage | Zone 9 window | Notes |
|---|---|---|
| Start indoors | Start indoors in August to September for autumn transplanting, or direct sow September to October | Germination takes 7–10 days |
| Direct sow outdoors | September to February; direct sow in September to October, or transplant autumn seedlings | — |
| Transplant outdoors | September to October for autumn crops; January to February for a spring crop | — |
| Days to maturity | 60–80 days | — |
| Cold tolerance | frost-tolerant | — |
Starting and planting
Collard greens can be started indoors or direct-sown in Zone 9. For an autumn crop, start seed indoors in August to September and transplant seedlings out in September to October, or direct-sow in September to October. For a spring crop, sow or transplant in January to February. Thin seedlings to the final spacing once they are up, and give them room — collards grow into large, leafy plants, and crowded plants stay small and are more prone to pests.
Spacing, sun and soil
Space plants 12–18 inches apart. Crowded plants compete for light, water and nutrients, stay small, and invite disease through poor airflow, so thin seedlings to the final spacing once they are established. Use the plant spacing calculator to work out how many plants fit in your bed at that spacing before you sow.
This crop needs full sun — at least six hours of direct sun a day where possible. In Zone 9, a south-facing bed or an open spot away from trees and fences gives the strongest growth; part-shade types do better with morning sun and afternoon shade.
Soil should be deep, fertile and free-draining, with a pH of 6.0–7.5. Test your soil through your local extension service before amending it, and dig in plenty of compost, which improves drainage in heavy soil and holds moisture in light soil.
Watering
Water needs are moderate: aim for steady, even moisture rather than feast-and-famine watering. Keep the soil evenly moist, especially while young plants are establishing — collards that dry out in a warm autumn spell grow slowly and can turn tough. Water at the base in the morning and mulch to hold moisture and keep the soil cool, which collards appreciate. In a dry spell, water deeply rather than sprinkling a little each day.
Companion planting
Good companions for collard greens include marigolds, basil, onions and lettuce. The companion planting finder can suggest combinations for your whole bed. Avoid planting collard greens where others of the same family (Brassicaceae) grew last year: rotate crops each season to reduce soil-borne disease and pest build-up.
Common pests and problems
Watch for cabbage worms, aphids, flea beetles and slugs. Inspect plants weekly — look under leaves, where small pests hide, and at the base of stems. Hand-pick larger pests, wash aphids off with a strong jet of water, and remove badly affected leaves rather than leaving them to spread a problem. Beyond pests, the main problems are weather-related: bolting in a hot spell, slow growth in cold soil, and damping off in seedlings kept too wet.
Harvest and storage
Start harvesting outer leaves once plants are well established, around 60–80 days from sowing, and keep picking the outer leaves while the centre keeps growing — a few plants harvested this way will feed a household for months. Leaves are at their best after a light frost, which sweetens them. Pick in the morning when leaves are crisp, and use them fresh within a few days, or blanch and freeze the surplus.
Collards are a cut-and-come-again crop in Zone 9: pick the outer leaves and leave the growing centre, and the plant keeps producing for months. In the coldest nights a little row cover protects young plants, but established collards handle Zone 9's winter lows of 20–30°F well.
Frequently asked questions
When should I plant collard greens in Zone 9?
Sow or transplant according to the table above, working from the average last frost of Jan 30–Feb 15 and the average first frost of Dec 1–15. These are zone averages — check your local extension service before planting out.
Can collard greens survive a frost in Zone 9?
Cold tolerance for this crop is listed as frost-tolerant. Hardy crops can take a light frost, frost-tolerant crops can take a light frost once established, and tender crops are killed or badly damaged by frost, so use row cover on cold nights.
How long do collard greens take to grow in Zone 9?
Germination takes 7–10 days and maturity takes 60–80 days from sowing or transplanting, according to standard published ranges.
Do collard greens taste better after frost?
Yes — a light frost sweetens collard leaves, and this is one of the reasons they are such a good Zone 9 winter crop. The mild winters here give you months of harvest, with the flavour improving as the weather cools. Leaves picked in warm weather, or after the plant bolts in spring, can taste bitter by comparison.
See the September planting guide for Zone 9 for what else to sow that month, and when to plant mustard greens in Zone 9 for a related crop.