Lemongrass (Cymbopogon citratus) is a tropical perennial grass characterized by its tall leaves and thick, pale culms, which provide its signature citrus flavor. Successful cultivation, whether in a garden bed or a container, depends heavily on replicating the warm, bright conditions of its native environment. Understanding the plant’s specific light requirements is the first step toward achieving a robust and fragrant harvest.
The Direct Answer: Lemongrass and Light
The plant thrives best when exposed to maximum sunlight. Lemongrass requires a minimum of six to eight hours of direct, unfiltered sunlight daily to support its vigorous growth. This high light intensity is necessary for photosynthesis and the development of thick, flavorful culms, which are the main harvestable part of the plant.
Plants receiving insufficient light will exhibit etiolation, resulting in thin, weak stalks that lack girth. A lack of adequate light also diminishes the concentration of essential oils, such as citral, reducing the herb’s signature lemony scent and taste. Placing the plant in partial shade will significantly reduce the potential yield and overall flavor profile. Gardeners in northern climates should use a south-facing location to maximize sun exposure and mimic the intense light of the tropics.
Essential Supporting Conditions
The right combination of soil, water, and temperature must be present for the plant to flourish. Lemongrass is a heavy feeder that requires rich, loamy soil high in organic matter. Mixing in aged compost or decomposed manure prior to planting ensures the soil is fertile and supports the plant’s extensive root system.
The soil must be consistently moist but possess excellent drainage to prevent waterlogging and root rot. Consistent moisture is important during the peak summer growing season, as the plant’s high growth rate demands a steady water supply. Lemongrass performs optimally in warm temperatures, ideally between 70°F and 90°F.
As a tropical species, lemongrass is sensitive to cold and cannot tolerate frost. Exposure to temperatures below 50°F will stunt its growth, and a hard freeze can be fatal. Gardeners in non-tropical zones should wait until all danger of frost has passed before moving the plant outdoors for the summer.
Ongoing Care and Harvesting
Once established, lemongrass benefits from regular feeding throughout the growing season due to its rapid growth and high nutrient needs. Applying a balanced, water-soluble fertilizer every four to six weeks sustains vigorous leaf and culm production. Incorporating a nutrient-rich top dressing of compost mid-season also provides a slow-release source of micronutrients.
Pruning involves periodically removing older, dead, or yellowing outer leaves to direct the plant’s energy toward new growth. Stalks are ready for harvesting when they reach a diameter of about half an inch and a height of at least 12 inches. The proper technique is cutting the stalk near the base of the plant, rather than pulling, to encourage new tillers and maintain the clump’s health.
In climates where winter temperatures fall below freezing, the plant must be protected. One common overwintering method is to dig up a section of the clump, pot it, and bring it indoors to a bright, south-facing window. Alternatively, the plant can be cut back and stored in a cool, dark location, such as a basement, and watered sparingly until spring.