How to Grow Lemongrass

Growing guide

Overview

Lemongrass is a tropical grass grown for its fragrant stalks, which flavor curries, soups, and teas. Gardeners love it for its fast growth and the fact that one clump keeps producing for years in warm climates. It needs full sun, steady moisture, and warm soil to thrive, and it will not survive frost.

Soil & planting prep

Lemongrass grows best in loose, loamy or sandy soil that drains well; it tolerates a range of pH but prefers slightly acidic to neutral (around 6.0–7.0). Before planting, work in compost to improve drainage and fertility. Space plants 24 to 36 inches apart, and set them so the base of the stalks sits just below the soil surface.

When to plant

Start seeds indoors 8 weeks before your last frost date, or buy starts closer to planting time. Transplant outdoors only after the last frost has passed and the soil has warmed to at least 60°F, since lemongrass is not frost-tolerant. In zones 8b–11b it can be planted in spring and grown as a perennial; in colder zones treat it as an annual container plant and move it indoors before the first fall frost.

How to plant

1. Start seeds indoors 8 weeks before last frost in a warm spot (75–85°F); keep the soil moist but not soggy.
2. Harden off seedlings for 7–10 days before transplanting by gradually exposing them to outdoor sun and wind.
3. Choose a site in full sun with well-drained soil; amend with compost if needed.
4. Set transplants 24–36 inches apart, planting at the same depth they were growing in their pots.
5. Water thoroughly after planting and keep the soil evenly moist until new growth appears.

5 common mistakes to avoid

• Planting outdoors too early: lemongrass is tropical and will stall or rot in cold soil, so wait until after your last frost date and the soil is at least 60°F.
• Letting the soil dry out completely: lemongrass needs consistent moisture, especially in containers, and drought stress causes tough, fibrous stalks and yellowing leaves.
• Growing in too-small containers: lemongrass forms a large clump and needs at least a 5-gallon pot to reach a harvestable size; smaller pots stunt it.
• Overwintering incorrectly: in cold zones, bring the pot indoors before the first frost and keep it in a bright, cool spot; leaving it outside even for one light frost can kill it.
• Harvesting the whole clump at once: cutting all stalks at soil level can kill the plant; instead, harvest only the outer stalks, leaving the center to regrow.

Harvesting & storage

Begin harvesting when stalks are about 12 inches tall and firm, usually 75–100 days after planting. Cut outer stalks at the base with a sharp knife, leaving the inner stalks to continue growing. Use fresh stalks right away, or store them in the refrigerator for up to two weeks; for longer storage, freeze chopped stalks or dry them.

Companion planting

Lemongrass grows well with other heat-loving herbs like basil, cilantro, and mint, and it can be planted near vegetables such as peppers and eggplant. Avoid planting it next to fennel, which can inhibit its growth.

Growing in containers

Lemongrass is well-suited to containers and performs best in a pot of at least 5 gallons. Use a well-draining potting mix, place it in full sun, and water when the top inch of soil feels dry; bring the pot indoors before frost in cold zones.

Pro tips

In cold zones, start indoors 8 weeks before last frost in a large pot. Bring indoors before frost. Divide clumps every 2-3 years. Harvest outer stalks 12 inches tall. Loves heat and full sun.