This guide answers when to plant lemongrass zone 7 with timing worked out from USDA Zone 7 frost-date averages, not guesswork. Lemongrass is the tall, citrus-scented grass behind Thai soups, curries and teas, and in Zone 7 it grows fast once summer heat arrives. The catch is cold: lemongrass is tender and has no frost tolerance at all, so Zone 7 gardeners grow it as a warm-season annual, starting plants indoors and moving them out only after the last frost. Given sun, warmth and steady water, a single plant becomes a thick clump of stalks by late summer.
This guide covers when to plant lemongrass zone 7, how to start it, what soil and spacing it needs, and how to harvest and store the stalks — plus how to keep a plant alive indoors through winter so you can start next spring with a head start.
Zone 7 at a glance
Zone 7 covers areas where average annual minimum temperatures run 0 to 10°F. The average last spring frost falls in the Mar 15–Apr 1 range and the average first autumn frost in the Nov 1–15 range — these are USDA zone averages, not exact dates for any one garden, so check your local extension service before planting tender crops outside. Use the frost date calculator to work out dates for your own garden, and browse the planting calendar hub for the full Zone 7 year.
When to plant lemongrass in Zone 7
| Step | Timing in Zone 7 |
|---|---|
| Start indoors | February to March, 6 to 8 weeks before the last frost |
| Transplant outdoors | Early to mid-April, after the last frost, once nights stay warm |
| Direct sow outdoors | Not recommended in Zone 7 — start indoors or buy plants |
| Grow as | A warm-season annual; lift and pot up before the first frost |
| Harvest | August to October, cutting stalks as needed |
The table above is the short answer. Lemongrass needs warm soil and warm nights, so do not rush it outside. Start seed or young plants indoors in February to March, and transplant in early to mid-April, after the average last frost range of Mar 15–Apr 1 has passed and night temperatures are reliably mild. If a late cold snap is forecast after transplanting, cover plants with a cloche or fleece overnight. Because it is grown as an annual here, the season ends with the first frost in the Nov 1–15 range — plan to harvest or lift plants before then. The Zone 7 April guide shows what else is happening in the garden in that month.
How to plant lemongrass
Start lemongrass indoors 6 to 8 weeks before the last frost, sowing seed shallowly in warm compost; germination takes 10–21 days and is faster with bottom heat. Grow seedlings on in bright light and harden them off for a week before transplanting, setting them out in early to mid-April once frost danger has passed. Space plants 24–36 inches apart: each one grows into a wide clump, and crowded plants stay thin and weak.
Give lemongrass full sun — at least six hours of direct sun a day for full-sun crops, or morning sun with afternoon shade where part shade is listed. Prepare the bed by forking in compost and removing stones and weeds, and check the soil pH: lemongrass prefers 6.0–7.0. Space plants 24–36 inches apart — the spacing in the table below — and sow seed at the depth on the packet, keeping the seedbed moist until germination, which takes 10–21 days.
| Fact | Range |
|---|---|
| Sun | full sun |
| Days to germination | 10–21 |
| Days to maturity | 90–120 |
| Spacing | 24–36 inches |
| Soil pH | 6.0–7.0 |
| Sowing method | start indoors |
| Cold tolerance | tender |
| Water needs | moderate |
Watering and feeding
Lemongrass has moderate water needs, but it grows best when it never dries out completely in summer. Water deeply at the base, especially in hot, dry spells, and water pots more often than beds since they dry out faster. Avoid waterlogging, which can rot the roots in heavy soil.
Companion plants and rotation
Good companions for lemongrass include tomatoes, peppers, marigolds, cabbage. Its strong scent is said to confuse pests, so it earns its place at the edge of a vegetable bed. Rotate annual crops each year rather than planting the same family in the same spot. Also see our guide to when to plant mint in Zone 7, another aromatic herb that pairs well with lemongrass in summer cooking.
Use the seed-starting calculator to plan combinations for your whole bed.
Pests and problems
The common pests for lemongrass are aphids, slugs, cutworms. In practice it has few problems in Zone 7: aphids may cluster on young growth and can be washed off with water, and slugs may nibble new shoots in a wet spring. Good air flow helps — do not crowd plants — and watering at the base rather than over the leaves keeps foliage dry. Cut away any damaged outer leaves and the plant will push out fresh growth quickly. Check plants weekly, looking under leaves as well as on top, and clear away dead leaves and debris where pests hide.
Harvesting and storing
Harvest stalks from August to October, once they are about as thick as a pencil and at least a foot tall. Cut the outer stalks at the base with a sharp knife, leaving the centre of the clump to keep growing. The tender pale lower part of the stalk is the part used in cooking; peel away the tough outer leaves first. Before the first frost, dig up the clump, pot it in compost and keep it in a bright, frost-free room over winter — it will regrow in spring and can go back outside after the last frost.
Frequently asked questions
When should I plant lemongrass in Zone 7?
Start indoors in February to March and transplant in early to mid-April, after the average last frost range of Mar 15–Apr 1. These are zone averages, so check your local extension service for your area.
Is lemongrass perennial in Zone 7?
No — it is tender and will be killed by the first frost in the Nov 1–15 range. Grow it as an annual, or lift the clump into a pot and overwinter it indoors in a bright, frost-free room.
How long does lemongrass take to grow?
About 90–120 days to maturity from sowing or transplanting, depending on variety and weather. Germination takes 10–21 days. Warm, sunny weather speeds growth; cold or cloudy weather slows it, so treat these as ranges, not exact dates.
What soil pH does lemongrass need?
A pH of 6.0–7.0 is ideal. Test your soil before planting and amend it if needed — your local extension service can test a sample and advise on what to add.