How to Grow and Care for a Lemongrass Plant

You know lemongrass as that tasty zing of flavor in a Thai soup or Indian curry. Its fragrance also makes it the perfect pick for soothing body scrubs and aromatic soaps. This graceful and tall grass is also a beautiful (and highly useful) addition to a garden, and even doubles as beautiful ornamentation in landscaping. 

"In the United States, it acts mostly as an annual, except for southern coastal states where it can get ample heat at humidity. In these regions, the plant acts as a perennial," says gardening expert Keegan Nesvacil, the co-founder of Woodland Tools Co. It also thrives year round in southwestern climates, where it stays warm and sunny, permitting it to receive enough water. 

Lemongrass is a hardy plant that's easy to grow and maintain. Here, learn how to keep yours in tip-top shape so you can enjoy its beauty and function.

Adding Lemongrass Plants to Your Yard

There are two ways to add lemongrass to your yard: You can grow them from seed or purchase more mature plants at a gardening center.

Growing From Seed

Lemongrass is easy to grow from seed, and starts sprouting within a couple weeks after planting. "For the best chances at success, lemongrass seeds should be planted just under the soil—about 1/16 of an inch down—because they need light to germinate," Nesvacil says. "It's also critical to not let the seed dry out, as it will stop the germination process."

To ensure proper conditions, place a clear cup over the top of the seed to help trap moisture and heat. Alternatively, grow your seeds in a small greenhouse that stays humid. It takes about 10 to 14 days for lemongrass seeds to germinate. Once it reaches 4 inches tall, you can transfer it to a sunny spot in your garden. 

Purchasing Lemongrass Plants

Alternatively, you can purchase mature lemongrass plants of various sizes. "When shopping for lemongrass plants at your local grocery store or market, be on the lookout for firm and fresh feeling stems," says David Harris, director of crop research and development at Freight Farms. "Also, opt for a younger, gentler, and ultimately more tender plant, as a younger plant has more room to grow once brought home."

How to Care for Lemongrass 

Lemongrass originates from tropical climates, so the plant itself requires a lot of light, heat, and moisture. This is true whether your lemongrass grows in a pretty pot on your kitchen windowsill, a hydroponic setting, or outdoors. 

Water

Lemongrass is a very water-intensive crop. "Because lemongrass grows in tropical places, it can handle more moisture than a non-tropical plant," Harris says. Water as often as needed to keep the soil moist. If you're growing hydroponically, keep the water oxygenated to promote good root health and a strong plant. 

Light

This plant prefers a warm and sunny environment. Aim for at least six hours of natural sunlight or an indoor LED light each day. 

Soil

Lemongrass does best in well-draining sandy soil that's nitrogen rich. It tends to struggle in clay soils. "Adding some mulch over the top will help to trap moisture in the soil," Nesvacil says.  

Fertilizer

To maintain healthy nitrogen levels, use a slow-release fertilizer to achieve optimal growth. "In summer months, I recommend using a fertilizer once a week," Harris says. "In colder months, switch to using fertilizer about once a month."

Pruning

Pruning helps maintain the shape and size of your lemongrass, and is also important for removing dead or diseased blades. Harris recommends trimming off about 4 to 6 inches anytime the grass grows surpasses 1 foot. "From there, you can let the leaves grow back and trim again," he says.  

Transplanting Lemongrass Plants

Lemongrass plants grow up to 5 feet tall and 2 feet wide, so you may find yourself wanting to divide and transfer the plant. Fortunately, this process is fairy simple, and you can even yield multiple plants from the mother plant. 

"When transplanting lemongrass, it is critical to keep as many roots intact as possible. To best do that, dig a shovel deep into moistened soil to capture all of the roots possible," Nesvacil says. Once extracted, cut and divide the plants if desired. Nesvacil notes that it's important to include several roots in each section for a successful transplant. 

Common Problems With Lemongrass Plants

Like all plants, lemongrass may be affected by various garden funguses, diseases, and distress. Using a fertilizer encourages healthy growth and pruning can prevent disease spread and nix dead leaves. Be on the lookout for the following signs your lemongrass plant needs some extra attention. 

Mold

Thanks to all that moisture, lemongrass is prone to experiencing mold. This typically shows up at the bottom of the crown. If indoors, move it to a place with better ventilation and monitor humidity levels. If outdoors, pull back on watering and keep an eye on the plant. 

For both indoor and outdoor plants, it’s helpful to remove any moldy blades to prevent spread. Another way to address mold is "to dilute hydrogen peroxide, transfer the hydrogen peroxide into a spray bottle, and spray that onto any lemongrass plants with mold," Harris says. 

White Spots 

Although lemongrass has natural repellent qualities—it's known for keeping mosquitos away—it is not immune to insects. "Depending on the time of year and your location, some lemongrass plants may experience spider mites, which are a sucking pest that leave a web and can cause white spots on the leaves," Harris says. 

Brown, Droopy Leaves 

Lemongrass may require a lot of moisture, but it's still susceptible to overwatering. Brown leaves are a sign your plant has received too much hydration. Pull back on the watering schedule, if possible. If Mother Nature keeps watering your plant, you may want to transfer it indoors to recover.  

Brittle Leaves 

While sunlight is important for lemongrass, it can receive too much. "Too much direct sunlight can result in its leaves becoming dry and brittle," Harris says. "A solution for this would be to tent the lemongrass with plastic to resemble a greenhouse effect or to move it inside in a container and use LED grow lights."