Kale is the cut-and-come-again hero of the Zone 10 winter garden: sow it in autumn and pick outer leaves for months, with the flavour actually improving after a cool night. It is one of the easiest brassicas to grow, and one of the most productive per square foot.
Zone 10 at a glance
USDA Zone 10 covers the warmest parts of the United States, including southern Florida, the southern tip of Texas, coastal southern California and Hawaii. Winters are mild, with average winter lows of 30 to 40°F, and the growing season runs nearly all year — frost is rare rather than a regular event.
The average last spring frost in Zone 10 is Jan 15–30 (frost rare), and the average first autumn frost is Dec 15–31 (frost rare). These are zone averages drawn from NOAA frost records, not exact dates for any one garden — always check your local extension service and the forecast before planting tender crops outside. Frost dates vary by microclimate, elevation and year, so treat them as a guide, not a promise. Use our frost date calculator for your zone's averages.
When to plant kale in Zone 10
Plant kale from October to March, sowing seed or setting out transplants in autumn for the longest harvest. Kale is hardy and frost-tolerant, growing best in cool weather, and in Zone 10 it can be picked from late autumn right through spring. Leaves mature 50–65 days after sowing, but you can start picking young leaves much sooner. Summer heat makes kale tough and bitter, so treat it as an autumn-to-spring crop. Because Zone 10 has a long, nearly year-round growing season, the question is rarely whether kale will grow, but whether you plant it in the right season — heat lovers go in after the last frost, cool-season crops go in for autumn and winter.
Kale planting at a glance
| Detail | Zone 10 guidance |
|---|---|
| Best planting window | October to March |
| Start indoors | Either — start indoors or sow directly |
| Days to germination | 7–10 |
| Days to maturity | 50–65 |
| Spacing | 12–18 in |
| Soil pH | 6.0–7.5 |
| Sun | full sun |
| Water needs | moderate |
| Cold tolerance | hardy |
All figures are broad published ranges from standard horticultural references, and they vary by variety, soil and weather. Check your local extension service for advice on your own garden.
Starting kale
Start kale indoors or sow directly; direct sowing is easy and reliable in Zone 10's mild autumn. Sow seed about half an inch deep and thin seedlings to their final spacing once they have a few true leaves — seed germinates in 7–10 days. For transplants, start seed indoors 4–6 weeks ahead and harden off before setting out. Sow a small batch every few weeks from October onwards for a continuous supply, and cover young plants with netting if cabbage whites are active.
Soil, spacing and sun
Kale needs full sun and fertile, well-drained soil with a pH of 6.0–7.5. Dig in compost before planting and side-dress with compost or a nitrogen feed during the season to keep leaves coming. Space plants 12–18 inches apart — kale grows into a big plant, and crowded plants make small, tough leaves. In Zone 10's sandy soils, compost holds the moisture and nutrients kale needs. Mulch to keep roots cool and the soil damp.
Watering and feeding
Kale has moderate water needs and grows best with steady moisture: dry plants make tough, bitter leaves. Water deeply once or twice a week and mulch well, especially in Zone 10's dry, sunny winters. A plant that is kept watered and fed will keep producing tender outer leaves for months. Avoid watering overhead late in the day, which leaves leaves wet overnight and invites disease.
Companion planting
Good companions for kale are marigolds, basil, onions and lettuce. Marigolds at the bed edge are said to confuse cabbage pests, and onions nearby may help mask the brassica scent. Lettuce fits between young kale plants and is usually harvested before the kale needs the space. Avoid planting kale near tomatoes and strawberries, and rotate brassicas to a fresh bed each year rather than following cabbage, broccoli or cauliflower.
Pests and problems
The pests to watch for are cabbage worms, aphids, flea beetles and slugs. Cabbage white caterpillars are the most common problem: check leaf undersides weekly and pick them off, or grow under insect netting. Aphids gather on young growth and can be blasted off with water. Flea beetles riddle seedling leaves but rarely kill a plant, and slugs nibble leaves on damp nights. Kale is tougher than most brassicas, and a well-fed plant usually outgrows minor damage.
Harvesting and storing kale
Harvest kale by picking the outer leaves first, 50–65 days after sowing, leaving the centre growing point to keep producing. Pick leaves while they are young and tender, and take only a few from each plant at a time so it keeps growing. A light frost sweetens kale, so late-season leaves are often the best flavoured. Strip the tough centre rib from mature leaves before cooking. Fresh leaves keep for about a week in the fridge, and blanched kale freezes well.
Frequently asked questions
When do I plant kale in Zone 10?
From October to March, with autumn sowing giving the longest harvest. It is a cool-season crop — check your local extension service for the best dates in your area.
Why does my kale taste bitter?
Usually heat or drought. Kale grown in hot weather, or left dry, turns tough and bitter. Grow it in the cool season and keep it watered.
How do I harvest kale without killing the plant?
Pick the outer leaves and leave the centre growing point alone. The plant will keep making new leaves from the centre for months.
How long does kale take to grow in Zone 10?
Seed germinates in 7–10 days and leaves are ready to pick in 50–65 days, with young leaves pickable sooner.
For the full year, browse the planting calendar hub. Nearby: october in Zone 10, Kale in Zone 9 and Cabbage in Zone 10. Use the seed spacing calculator and the harvest date calculator to plan your own dates.