Lemongrass is a tall, tropical grass that is one of the easiest and most rewarding herbs for Zone 10. It is a tender perennial here, growing nearly all year into a clump of lemon-scented stalks used in Thai and Vietnamese cooking, teas and insect repellents.
In most of Zone 10 lemongrass survives winter outdoors, dying back only in the coldest spots and regrowing from the roots in spring. One clump is enough for a household — it grows fast in the warm season and can reach several feet tall and wide, so give it room.
Zone 10 at a glance
USDA Zone 10 covers the warmest parts of the United States — South Florida, the southernmost 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, with frost a rare event rather than a season marker.
The average last spring frost in Zone 10 is Jan 15–30, and the average first autumn frost is Dec 15–31 — and frost is rare in most Zone 10 gardens. 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.
| Detail | Zone 10 guidance |
|---|---|
| Average winter low | 30 to 40°F |
| Average last spring frost | Jan 15–30 (frost rare; average/range) |
| Average first autumn frost | Dec 15–31 (frost rare; average/range) |
| Days to germination | 10–21 days |
| Days to maturity | 90–120 days |
| Sowing | start indoors |
| Sun | full sun |
| Soil pH | 6.0–7.0 |
| Spacing | 24–36 inches |
| Water needs | moderate |
| Cold tolerance | tender |
When to plant lemongrass in Zone 10
Plant lemongrass in Zone 10 from February through May, after the average last frost of Jan 15–30, from nursery plants or divisions — seed takes 10–21 days to germinate and plants take 90–120 days to establish, and bought plants or stalks from the grocery store root far faster. The average first autumn frost is Dec 15–31, and frost is rare, so the plant has a long warm season to grow. Wait until the soil is warm and night temperatures are reliably mild before planting out, since cold, wet soil checks its growth. In the coldest Zone 10 pockets, a light frost may brown the leaves, but the crown usually survives and regrows.
The planting calendar hub gives the Zone 10 picture month by month, and the frost date calculator can help you work out exact sowing dates.
Starting lemongrass in Zone 10
Start lemongrass from a nursery plant, a division of an established clump, or a fresh stalk from the grocery store — trim the top, stand the stalk in water until roots appear, then pot it up. Plant out 24–36 inches apart in full sun, in rich, moisture-holding soil, and water well for the first few weeks until established. Lemongrass also grows well in a large pot, which makes it easy to move under cover if a rare cold night is forecast. Keep the crown clear of mulch piled against the stems, which can rot in humid weather.
Soil, spacing, sun and water
Lemongrass needs full sun in Zone 10 — in the hottest months a little afternoon shade keeps leaves tender and prevents scorch, but too much shade weakens flavour and growth. It grows best in soil with a pH of 6.0–7.0. Lemongrass likes rich, moisture-holding soil with a pH of 6.0–7.0. Dig in plenty of compost before planting, and feed lightly through the warm season for the fastest growth. Space plants 24–36 inches apart so air can move between them; crowded plants stay damp and invite disease in Zone 10 humidity. Water needs are moderate: keep the soil evenly moist, especially while plants are young and in warm weather, and mulch to hold moisture and keep roots cool. A raised bed or a pot with drainage holes is often the easiest way to get the drainage right, and the soil volume calculator helps you work out how much mix a bed or container needs.
Companion planting
Good companions for lemongrass include tomatoes, peppers, marigolds, cabbage. Lemongrass grows well near tomatoes, peppers and cabbage, and its strong scent is said to confuse pests. It also makes a useful tall screen or windbreak at the back of a bed — just keep it away from low herbs it would shade out. The March guide for Zone 10 in March shows what else is going in at the same time.
Our guide to when to plant mint in Zone 10 shows how to time a second crop alongside it. For comparison with a cooler zone, see when to plant lemongrass in Zone 9.
Pests and problems
The common pests to watch for with lemongrass are aphids, slugs, cutworms. Aphids may gather on young growth — wash them off with water. Slugs can nibble young shoots in damp weather, and cutworms occasionally attack new transplants. Lemongrass is generally trouble-free in Zone 10; cold and waterlogged soil cause more losses than pests. Check the undersides of leaves weekly — most Zone 10 pest problems are small when caught early and much harder once they spread. Avoid spraying broad insecticides on herbs you plan to eat; a strong jet of water, hand-picking and encouraging ladybirds and other beneficial insects will deal with most outbreaks.
Harvest and storage
Begin harvesting lemongrass once the clump is established, about 90–120 days after planting, and pick all year in Zone 10. Harvest by pulling or cutting the thickest outer stalks at the base, choosing stalks at least half an inch thick — the tender, pale lower part is the part used in cooking. Use stalks fresh, or chop and freeze them; dried lemongrass keeps some flavour but is milder. Leaves can be used for tea, fresh or dried. In late winter, cut the whole clump back hard to make way for fresh spring growth.
Frequently asked questions
When should I plant lemongrass in Zone 10?
Plant from February through May, after the average last frost of Jan 15–30, from nursery plants, divisions or rooted stalks.
Is lemongrass perennial in Zone 10?
Yes — it is a tender perennial here. It grows nearly all year and survives most Zone 10 winters, regrowing from the roots if the top is frosted.
Can I grow lemongrass from a grocery store stalk?
Yes — choose a fresh, firm stalk, trim the top, stand it in water until roots appear, then pot it up and plant out once it is growing strongly.
How do I stop lemongrass taking over?
Give it room at the back of a bed, or grow it in a large pot. Divide the clump every year or two and remove the outer pieces you do not need.