Lemongrass

Lemongrass (Cymbopogon citratus) stalks at a specialty grocery store run $2-4 each for a few inches of trimmed stalk - effectively $25-40 per pound equivalent when you do the math. Grow your own and you’re cutting stalks that are 18-24 inches long and a full inch in diameter at the base, which is more material per stalk than you’ll ever find at retail (USDA AMS Specialty Crop Market News, 2023). The economic case is straightforward. The practical case - that it grows as a massive, self-dividing tropical grass that gives you free transplants every season - makes it better.

What it actually is

Lemongrass is a tall perennial tropical grass in the family Poaceae, native to South Asia. C. citratus is the West Indian lemongrass cultivated for culinary use; the closely related C. flexuosus (East Indian lemongrass) is more commonly used for essential oil production. For kitchen purposes, C. citratus is what you want.

The edible portion is the swollen, pale lower stem - the inner stalk - which contains the essential oil dominated by citral, the compound responsible for the clean lemon-citrus scent and flavor. The upper leaves are fibrous and not eaten, but they’re usable for teas, aromatics in soups, and flavor infusions where they’re later removed. The stalks are used in Thai, Vietnamese, and other Southeast Asian cooking: in curry pastes (minced finely), in broths (bruised and simmered whole), and in marinades.

In USDA zone 9 and above, lemongrass is a perennial and the clumps expand year over year. In zones 7-8, it may overwinter outdoors with heavy mulching. In zones 4-6, treat it as a large annual or dig up a division in fall, pot it, and overwinter it indoors as a houseplant in a sunny window. It will re-establish quickly when returned to the garden in spring.

The ROI case

A pot of lemongrass starts (or a few seeds) costs $3.99-5.99. From a single clump planted in spring, you can harvest 8-15 stalks by midsummer - each stalk representing $2-4 at retail. That’s $16-60 in retail value from a single clump in the first year.

The second-year economics are better. A mature lemongrass clump naturally divides into 4-8 or more separate sections that can each be transplanted independently. You start with one plant and end the season with the material for a full row at zero additional seed cost. The division process is simple: dig the clump in fall, pull or cut it apart at the root base into sections with 3-5 stalks each, and pot up what you’re overwintering.

At $5.00/lb average retail (USDA AMS Specialty Crop Market News, 2023), each pound you harvest represents a meaningful offset against what you’d otherwise pay for inferior, older store product.

Growing requirements

Lemongrass is a tropical plant and behaves accordingly. It will not establish in cold soil - wait until nighttime temperatures are consistently above 55°F before transplanting. In most of the US, that means late May to mid-June.

It needs full sun (6-8 hours minimum) and soil that drains well. Despite wanting regular water, it will not tolerate standing water or saturated soil - roots rot in poorly drained conditions. Soil pH of 5.5-7.0. Rich, fertile soil with good organic matter produces the largest clumps and most vigorous stalk growth.

Space clumps 3-4 feet apart - lemongrass grows 3-5 feet tall and 2-4 feet wide at maturity. In a small garden, one or two clumps is typically enough for a household.

Water 1-1.5 inches per week during active growth. Once established (after 6-8 weeks), it tolerates short dry periods without significant damage, but consistent moisture produces better stalk development.

What goes wrong

Cold damage is the primary concern in zones 6 and below. A hard frost kills lemongrass to the ground. Where winters are cold, move potted divisions indoors before first frost - typically late September in zone 6. Outdoor plants can be mulched heavily (6-8 inches of straw) in zones 7-8 and will often survive, though they may die back completely and regrow from the roots.

Rust (Puccinia spp.) occasionally causes orange-red pustules on older leaves in humid conditions. Remove affected leaves; improve air circulation. This is rarely serious enough to affect yield.

Spider mites can establish on indoor overwintered plants in dry heated spaces. Inspect weekly and treat with insecticidal soap or neem oil at first sign. Increase humidity around the plant if possible.

Slugs feed on young growth early in the season, particularly in cool, wet springs. Diatomaceous earth around the base of the plant provides some deterrence.

Lemongrass is allelopathic - its root exudates suppress some neighboring plants. Give it space from small or sensitive companion plantings.

Harvest and storage

Stalks are ready to harvest when they’re at least 12-18 inches tall and 0.5 inch or more in diameter at the base. To harvest, grip a stalk firmly at the base and pull it away from the clump with a twisting motion, or cut it as close to the ground as possible with a sharp knife. The tender, white-to-pale-green interior is what you want; the outer green leaves are woody and fibrous but usable for flavoring.

Fresh lemongrass keeps in the refrigerator for 2-3 weeks wrapped loosely. Stalks freeze well whole - seal them in bags and use directly from the freezer in cooked applications. You can also dry the leaves and store for tea.

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Related crops: Basil, Mint, Cilantro

Related reading: Beginner Homestead Crops - which crops make sense for a first homestead planting, including tropical herbs worth overwintering