Fact sheet: Lemongrass
Lemongrass (Cymbopogon citratus) is an easy to grow herb that requires warm, humid conditions, full sunlight and plenty of moisture. It is a tender perennial that is commonly grown as an annual in cooler areas. Plant lemongrass after the last frost or grow it in a pot and move it outdoors after temperatures warm in the spring. Nurseries and seed companies will generally sell small starter plants. Fresh stalks of lemongrass (leaves and roots absent) can be purchased at grocery stores specializing in Asian cuisine and will root in a glass of water in about 2 weeks. Water and feed regularly from June through September to maximize growth. Bring potted plants indoors when temperatures cool in the fall.
Only two of the 55 species of Cymbopogon are used as lemongrass. The East-Indian lemongrass (Cochin or Malabar grass) and the West-Indian lemongrass are typically used for cooking. Check with specialty nurseries and garden centers for available plants.
How to Grow
Soils: Lemongrass prefers well-drained, moist, rich loam soil with high organic content. It will tolerate poor soils if provided adequate moisture and good drainage. Water logged soils should be avoided.
Soil Preparation: Before planting, amend soils with 2 to 4 inches of organically rich compost. Work it 4 to 6 inches deep into the soil. For outdoor grown potted plants, apply a ½ strength solution of a nutrient balanced water soluble fertilizer every week to 10 days to maximize growth.
Plants: Divide last year’s lemongrass clumps or purchase starter plants from local nurseries. Lemongrass is rarely grown from seed. Plant the divisions after the danger from frost has passed. Lemongrass grows slowly until the heat of summer arrives, then it increases in size dramatically. Typically plants will produce several harvestable stalks by the end of the summer.
Planting and Spacing: Lemongrass divisions should be spaced 3 feet apart in the garden since it can grow 3 to 6 feet tall and 3 feet wide, if water, fertilizer and growing conditions are optimal. In cooler areas, lemongrass should be planted in a pot. After harvest or before the first fall frost, save a 6 inch section of the bulbous shoot base. These sections with attached roots can also be divided and potted the following year. Smaller container plants can be overwintered indoors. Divided or containerized plants need to be grown in a warm, bright, sunny location.
Water: Lemongrass is native to tropical climates, so it prefers regular rainfall and more humid conditions. In a dry climate, it should be misted and regularly watered. Water lemongrass by hand or use flood irrigation rather than irrigate with sprinklers. If
grown in a container, water regularly so the pots do not dry out.
Fertilization: Like other grasses, lemongrass requires lots of nitrogen during the summer. It should be feed weekly with a half-strength solution of a balanced soluble fertilizer from June through September. Supply a similar fertilizer monthly for plants in the ground.
Weeds: Weeds don’t compete well with mature lemongrass. Hand weeding may be required when plants are small.
Pests and Disease: Lemongrass is generally free of pests and diseases when grown correctly.
Insects Identification Control
Spider Mites: Piercing type pest that feed on plants cell contents causing tiny yellow or white speckling. Problem mostly on indoor plants. Use insecticidal soaps, registered insecticides or spray plant with a forceful jet of water to dislodge the insects.
Diseases Symptom Control
Leaf Blight: Reddish brown spots on leaf tips and margins; appear to be prematurely drying. Spray with registered fungicides if positively identified or hand remove blighted leaves.
Little Leaf or Grassy Shoot: Stunted growth of normal inflorescence. Spray with registered fungicides if positively identified.
Harvesting and Storage
In cooler areas, harvesting occurs at the end of the growing season just before the first fall frost. However, lemongrass can be harvested at anytime, once the plant stalks have reached ½ inch thick. To harvest, cut stems at ground level, or push an outside stem to the side, twist and pull off or cut with a knife. Discard the outer woody layers and the leaves. The entire plant of the lemongrass can be used for cooking. Plant stalks are quite hard, so they are usually mashed and simmered in water to extract the lemony flavor. Stalks can also be crushed and placed in the bottom of foil wrappings with meat or vegetables. Once cooked the tender interior core can be sliced and used in a variety of dishes. The lemongrass leaves are used to flavor teas, soups and sauces. Dry lemongrass leaves in the sun or oven and use like bay leaf in soups and teas. Lemongrass can be frozen up to 6 months.
Stalk productivity depends on how well plants are maintained. It grows rapidly if supplied with sufficient water, fertilizer, sunlight and humidity. Productivity can be improved by dividing older plants. Older stalks should be harvested first to promote new stalk growth. Lemongrass grown indoors will not produce as many stalks, due to low light conditions. It comes back quickly when returned to the garden the next spring.
Nutrition and Uses
Lemongrass oil is used in soap, perfume, makeup, hair products, a cleaning agent, antifungal agent, incense and potpourri. It is also used as an effective, non-toxic insect repellent. Lemongrass is rich in vitamin A and reportedly has many medicinal benefits. For more information on herbal medicines, refer to a reliable information source for details on the benefits or hazards. One such source is the National Institutes of Health’s herbal medicine Web site: http://www.nlm.nih.gov/medlineplus/herbalmedicine.html
Planted in Nassau County Extension Demonstration Garden
Bown, D. 1995. Encyclopedia of Herbs and Their Uses. New York: Houghton Mifflin.
Bremness, L. 2002. Smithsonian Handbooks: Herbs. Dorling Kindersley Publishing, 304p.
Kemper Center for Home Gardening. 2008. Missouri Botanical Garden. http://www.mobot.org/gardinghelp/plantfinder/plant .<asp?code=A504.
by Terra Linse and Dan Drost Utah State University