Cymbopogon flexuosus. Lemongrass is a tropical plant from the grass family (Poaceae) that will grow well in temperate regions if given the right conditions. Sow Lemongrass seeds indoors in late winter using bottom heat or a seedling heat mat. Maintain moist conditions and a temperature around 21°C (70°F), and the seeds will germinate in 5 to 21 days. Be sure to use sterilized seed starting mix, and either a clear dome over your seedling tray, or sealed into a plastic bag to maintain moisture. Transplant outdoors or into containers in full sun once the weather has warmed up in early summer. At the end of summer move container plants into a frost free environment with good air circulation. Reduce watering to almost none, making the soil barely moist once a week.
When using Lemongrass in the kitchen, remove any loose, outer layers. Either use whole pieces, crushed slightly with a pestle or under the back of your cleaver, or slice sections very thinly in cross section. This will help break up the strong fibres of the grass stalks.
Lemongrass is a tropical grass that thrives in summer heat. It is well suited to container growing, and ideal for greenhouse cultivation. It can be grown as a perennial where winters are mild, but care must be taken to control moisture in the soil over winter, and to provide protection from frost. It is somewhat challenging to grow, but the reward is fresh, strongly aromatic stalks with very minimal carbon footprint. Hopefully these helpful tips will instruct on how to grow lemongrass from seed.
Season & Zone
Season: Hot season
Exposure: Full sun
Sow seeds indoors in late winter. Transplant outdoors only when night time temperatures are steadily above 10°C (50°F).
Press the seeds gently 5mm (1/4″) into pre-moistened, sterilized seed starting mix. Use seedling trays with plastic domes, or containers sealed inside large plastic bags. Use bottom heat from a Seedling Heat Mat to maintain a soil temperature of 21°C (70°F). Keep seed trays or containers in a dark room or cupboard. Seeds should germinate in 5 to 21 days. The trick is to maintain a moist, not wet, environment. Once seedlings appear, remove the dome or plastic bag, and move them into full sun or beneath strong, full spectrum, artificial light.
Harden seedlings off in early summer by gradually exposing them to full sun and cooler temperatures. Transplant individual seedlings into 5 gallon (or larger) containers, and apply high nitrogen organic fertilizer like Alfalfa Meal or Blood Meal at the time of transplanting. Just mix 1/2 cup into the soil before transplanting. Keep the soil relatively moist throughout the growing period, watering at least 2 or 3 times a week – more in hot weather.
At the end of the growing season, once night time temperatures begin to approach 10°C (50°F), cut back lemongrass plants to 15-20cm (6-8″) tall, reduce watering, and discontinue feeding. Move plants to a bright, airy spot, protected from frost. Water only enough to keep the soil barely moist to nearly dry. If plants seem congested, consider dividing them into clumps in early spring, and potting them on. Resume watering and feeding once spring growth appears.
Use secateurs to snip whole stalks from the base of the plant as needed. Stalks should be at least 15mm (1/2″) thick before picking. Lemongrass dries well for use as a tea, and whole stalk segments can be bundled and frozen for use in soups and curry paste all winter long.