Lemongrass is a fragrant, tropical grass prized globally for its bright, lemon-like aroma without the acidity of citrus fruits. Native to South Asia and Maritime Southeast Asia, it is a staple in traditional cuisines, particularly Thai and Vietnamese dishes, where it imparts a complex, subtle sweetness with hints of mint and ginger. Beyond its culinary appeal, the plant and its essential oil have a long history of use in folk medicine for applications ranging from digestion support to calming effects, driven by compounds like citral and various antioxidants.
When and How to Harvest Lemongrass Stalks
Harvest lemongrass stalks when they have reached maturity to maximize their aromatic compounds. Look for stalks at least one-half inch thick and 12 to 18 inches tall, which typically occurs four to six months after planting. The heat of late summer or early fall often concentrates the volatile oils, yielding the most intensely flavored stalks.
To ensure the plant continues to produce new shoots, harvest only a few stalks from the outer edges of the clump. The most flavorful portion is the thick, pale base closest to the soil, so use a clean, sharp knife or garden shears to make your cut. Snip the stalk as close to the ground line as possible, taking care not to pull or yank, which can damage the root system.
Cutting the stalk cleanly promotes healthy regrowth and encourages the plant to become bushier and more productive. Wearing gloves is advisable during harvest, as the long, narrow leaves can have sharp edges that may irritate the skin.
Preparing and Storing Lemongrass
Begin preparation by trimming off the tough, woody root end and the dry, leafy green tops. Peel away the dry or loose outer layers of the stalk until you reach the pale, firm, and tightly bound inner core. This inner core is the most tender and flavorful part.
For short-term storage, whole stalks can be kept fresh in the refrigerator for up to three weeks. Stand the trimmed stalks upright in a glass with about one inch of water, covering the tops loosely to prevent moisture loss, and changing the water daily. Alternatively, stalks can be wrapped in a damp paper towel and sealed within a plastic bag before refrigeration, offering freshness for about two weeks.
For a longer-lasting supply, freezing is an excellent option as it helps break down the fibrous structure slightly. Whole stalks can be frozen in an airtight bag, but for maximum convenience, finely chop or mince the tender inner core first. The minced lemongrass can be frozen in single-tablespoon portions, such as in ice cube trays with a small amount of neutral oil, retaining quality for up to six months.
Culinary and Non-Culinary Applications
Culinary Uses
For applications like simmering in curries, soups, or stocks, bruise or smash the lower four to eight inches of the stalk with the back of a knife or a pestle. This crushing action ruptures the tough fibers, effectively releasing the aromatic oils into the liquid. The whole or large pieces of stalk are typically removed before serving, as they remain too fibrous to chew.
When a recipe calls for a more intense burst of flavor and the herb to be fully incorporated, such as in marinades, curry pastes, or stir-fries, the pale inner core must be finely minced or pureed. Only the tender, non-fibrous heart of the stalk should be used for mincing to ensure a pleasant texture. The tough outer layers and leafy tops, although not suitable for eating, can be saved and steeped to brew a soothing herbal tea.
Natural Insect Repellent
Beyond the kitchen, the powerful scent of lemongrass makes it useful as a natural insect repellent. The essential oil contains geraniol and citronellol, which deter mosquitoes and other pests. A simple repellent spray can be made by boiling crushed lemongrass pieces in water for 10 to 15 minutes. This strained liquid can be cooled and sprayed, utilizing the plant’s natural chemical properties.