Leeks are a quiet winter staple in Zone 9: slow to grow, almost trouble-free, and happy standing in the ground through winter until you need them — the vegetable garden's savings account.
Zone 9 at a glance
USDA Zone 9 covers the warmest parts of the southern United States, including much of Florida, southern Texas, southern Louisiana, southern Arizona and coastal California. Winters are mild, with average winter lows of 20 to 30°F, and the growing season runs nearly all year.
The average last spring frost in Zone 9 is Jan 30–Feb 15, and the average first autumn frost is Dec 1–15. 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. The average last spring frost in Zone 9 is Jan 30–Feb 15, and the average first autumn frost is Dec 1–15. These are USDA 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. Use our frost date calculator for your zone's averages.
When to plant leeks in Zone 9
Start seed indoors in late summer and transplant in autumn (September to November); leeks stand through winter and are ready in late winter to spring. The average last spring frost in Zone 9 is Jan 30–Feb 15, and the average first autumn frost is Dec 1–15. Because Zone 9 has a long, nearly year-round growing season, the question is rarely whether leeks will grow, but whether you plant it in the right season for the crop — heat lovers go in after the last frost, cool-season crops go in for autumn and winter.
Leeks planting at a glance
| Detail | Zone 9 guidance |
|---|---|
| Best planting window | Start seed indoors in late summer and transplant in autumn (September to November); leeks stand through winter and are ready in late winter to spring. |
| Start indoors | Start seed indoors 8–10 weeks before transplanting |
| Direct sow / transplant | Transplant seedlings outdoors September–November |
| Days to germination | 7–14 |
| Days to maturity | 90–120 |
| Spacing | 6–8 in |
| Soil pH | 6.0–7.0 |
| 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 leeks
Leek seed germinates in 7–14 days. Start seed indoors in late summer, or sow in a nursery bed and transplant in autumn — leeks transplant well. Sow thinly in trays, and when seedlings are pencil-thick, trim the tops and roots slightly and plant them into holes made with a dibber, about six inches deep. Do not fill the holes with soil: water them in, and the soil will wash in around the stems. This deep planting is what gives leeks their long white shanks. In Zone 9, autumn transplanting gives leeks that stand through winter.
Soil, spacing and sun
Leeks need full sun and rich, well-drained soil with a pH of 6.0–7.0. Work compost into the bed before planting. Space plants 6–8 inches apart in rows. As leeks grow, earth up soil around the stems or mulch deeply to blanch the shanks white — the white part is the sweetest. Keep the bed weed-free, because leeks compete poorly with weeds. Leeks also grow well in deep containers, where the depth helps blanching.
Watering and feeding
Leeks have moderate water needs and want steady moisture while they are growing, especially in their first weeks after transplanting. Water deeply once or twice a week, and mulch to hold moisture. Once established, leeks are fairly drought-tolerant, but regular water gives thicker shanks. In Zone 9's dry autumn spells, check the bed weekly. Stop heavy watering as leeks finish in spring; wet soil at that stage encourages rot.
Companion planting
Good companions for leeks are marigolds, basil, onions and lettuce. Leeks are famously good partners for carrots: each is said to deter the other's pests, so they are often grown in alternate rows. Lettuce fills the gaps between young leeks. Avoid planting leeks near peas and beans, which grow poorly alongside alliums. Rotate leeks to a fresh bed each year, away from onions, garlic and shallots.
Pests and problems
The pests to watch for are aphids, slugs and cutworms. Aphids cluster on leaves in spring — wash them off with water. Slugs can damage young transplants in wet weather; check after rain. The main pest to watch for in Zone 9 is leek moth, whose caterpillars tunnel into stems — cover with fine mesh from transplanting if it is a problem in your area. Leeks are otherwise one of the toughest, least troubled winter crops.
Harvesting and storing leeks
Harvest leeks 90–120 days from transplanting, when shanks are thick and white — usually in late winter to spring. Lift them as needed through winter: leeks stand well in the ground, so there is no rush. Use a fork to lift them, working from the edge of the row, and trim roots and tops. Leeks keep about two weeks in the fridge, or stand in damp sand in a cool place. They freeze well after slicing and blanching. In Zone 9, autumn-planted leeks often keep producing into spring.
Frequently asked questions
When should I plant leeks in Zone 9?
Start seed indoors in late summer and transplant in autumn, September to November. Leeks stand through winter and are ready in late winter to spring — check your local extension service for the best dates in your area.
How do I get long white leek shanks?
Plant seedlings deep in dibber holes and earth up soil around the stems as they grow. The white part is the part kept out of the light, so deep planting and hilling are the whole trick.
Can leeks stay in the ground all winter?
Yes — that is one of their best features. Leeks stand well through Zone 9 winters and can be lifted as needed, so there is no rush to harvest them all at once.
How long do leeks take to grow in Zone 9?
Seed germinates in 7–14 days and leeks mature in 90–120 days from transplanting, so autumn-planted leeks are typically ready in late winter to spring.
For the full year, browse the planting calendar hub. Nearby: october in Zone 9, Leeks in Zone 7 and Onions in Zone 9. Use the seed-starting calculator and the soil volume calculator to plan your own dates.