Lemongrass is the tall, citrus-scented grass for Thai cooking — the stalks that flavour soups, curries and teas — and it is a tropical plant that loves Zone 8's long, hot summers. The catch is winter: lemongrass is tender and will not survive a Zone 8 frost outdoors, so grow it as a summer annual or overwinter it under cover. This guide covers when to plant lemongrass in Zone 8 and how to get a good harvest before the cold arrives.
Zone 8 at a glance
Zone 8 covers parts of the southern United States, the Pacific Northwest coast and parts of California, where average winter lows run 10 to 20°F. The average last spring frost falls Mar 1–15 and the average first autumn frost Nov 15–Dec 1. Those are USDA zone averages drawn from NOAA frost records, not exact dates for any one garden — frost dates vary by microclimate, elevation and year, so always check your local extension service and the forecast before planting. Use the frost date calculator for your own averages, and browse the planting calendar hub for the full Zone 8 year.
When to plant lemongrass in Zone 8
| Step | Timing in Zone 8 |
|---|---|
| Start indoors | February to March, from seed or stalks |
| Transplant outdoors | May, after the last frost, once nights are warm |
| Plant from stalks | May, rooting shop-bought stalks in water first |
| Harvest | August to November; 90–120 days to maturity |
| Overwinter | October to November, lift and pot up before the first frost |
Lemongrass is tender and must wait until after the average last frost of Mar 1–15 — and then until nights are warm. The Zone 8 May guide is the safe transplant window. It needs the whole hot summer to grow, and it must be lifted or protected before the first autumn frost of Nov 15–Dec 1. Use the seed starting calculator to work out dates for your own garden.
How to start lemongrass
Start seed indoors in February to March on a warm windowsill — germination takes 10–21 days and needs warmth. Or root fresh stalks bought for cooking: trim the tops, stand them in water on a sunny sill until roots appear, then pot them up. Harden plants off for a week before planting out in May, spacing them 24–36 inches apart — a single plant grows into a large clump by autumn.
Soil, spacing and sun
Lemongrass wants full sun and rich, moisture-holding soil. Fork in plenty of compost and aim for a soil pH of 6.0–7.0. Space plants 24–36 inches apart, because each plant becomes a wide clump of tall blades. It grows very well in a large container, which makes overwintering easy — just carry the pot indoors in autumn.
| Fact | Range |
|---|---|
| Sun | full sun |
| Days to germination | 10–21 |
| Days to maturity | 90–120 |
| Spacing | 24–36 in |
| Soil pH | 6.0–7.0 |
| Sowing method | start indoors |
| Cold tolerance | tender |
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.
Watering and feeding
Water needs are moderate to generous: lemongrass likes moist soil and grows fastest when it never dries out. Water deeply once or twice a week in summer, more often in pots, and mulch thickly to hold moisture. In Zone 8's hot summers it will drink heavily — a thirsty lemongrass stops growing and the leaf tips brown.
Companion planting
Tomatoes, peppers, marigolds and cabbage are listed companions, and lemongrass is a useful neighbour: its strong citrus scent is said to confuse pests, and it is often planted at the edge of the vegetable garden. Give it its own space, though — a mature clump shades smaller plants and drinks a lot of water. The companions listed for lemongrass in standard references are tomatoes, peppers, marigolds, cabbage.
Pests and problems
Aphids, slugs and cutworms are the listed pests, but lemongrass is generally vigorous and trouble-free in Zone 8's hot summers. Watch for slugs on young plants and wash aphids off with water. Rust can appear in humid weather — remove affected leaves and improve airflow by thinning the clump. The pests most often listed for lemongrass are aphids, slugs, cutworms. Inspect plants weekly, act early while numbers are small, and encourage natural predators such as ladybirds and hoverflies.
Harvest and storage
Start harvesting 90–120 days after planting, from August onwards, once stalks are at least half an inch thick. Cut outer stalks at the base with a sharp knife, leaving the centre of the clump to keep growing. Peel away the tough outer layers and use the tender pale core. In October to November, before the first frost, lift the plant and pot it up to overwinter in a bright, frost-free place, watering sparingly — or take cuttings to start again next spring. Lemongrass freezes well: chop stalks and freeze them in bags.
Frequently asked questions
When should I plant lemongrass in Zone 8?
Start indoors in February to March and transplant in May, after the average last frost of Mar 1–15 and once nights are warm. It is tender — frost will kill it outdoors.
Will lemongrass survive winter in Zone 8?
Not outdoors — it is a tropical plant and Zone 8 winters reach 10 to 20°F. Lift it in October to November and overwinter the pot in a bright, frost-free place, or grow it as an annual and start fresh each spring.
Can I grow lemongrass from shop-bought stalks?
Yes — trim the tops, stand the stalks in water on a sunny windowsill until roots appear, then pot them up. It is often faster and more reliable than growing from seed.
Why are my lemongrass leaves browning?
Usually drought or cold. Lemongrass is thirsty in summer — water deeply and mulch — and it browns at the first cold night. Trim off brown tips and protect the plant from frost.
For the full year, browse the planting calendar hub. Compare with Lemongrass in Zone 6, and see also Basil in Zone 8.