Lemon grass (Cymbopogon citratus) grows in full sun and warm, humid climates. The clumps grow 4 to 6 feet tall and 6 feet wide. A tasty addition to the herb garden, lemon grass is used in the kitchen to add a light lemony flavor a variety of dishes. Start lemon grass seeds indoors in January and transplant them outside after the last frost has passed. Harvest the stalks before the first frost or pot up the plants and bring them inside for the colder months.
Fill a planting tray with a damp seed-starter soil mix. Scatter the lemon grass seeds over the top of the soil and cover with 1/4 inch of damp seed-starting mix. Slide a plastic bag over the tray and loosely tie it down to create a humid environment.
Put the tray in a greenhouse or on a windowsill where the seeds get at least six hours of filtered sun per day. Keep the seeds between 65 and 85 degrees Fahrenheit to stimulate germination. Mist the soil daily with water to keep the soil consistently damp. Look for signs of germination in five to six days.
Transplant the seedlings into individual 2-inch pots when they are 1 to 2 inches tall. A flat of individual 2-inch cells is ideal. Fill the pots or cells with damp potting soil. Slide a dowel under the seedlings and gently remove them from the tray. Place one lemon grass seedling into each cell and press the soil down around the roots.
Keep the lemon grass seedlings in a warm, humid greenhouse or covered porch where the temperature is above 65 degrees Fahrenheit. Water every two days to keep the soil damp. The seedlings will be big enough to transplant outside in two months.
Spread a 4-inch layer of compost over the planting area and work it 6 inches into the soil using a garden fork or tiller. Dig a 2-inch hole for each seedling in the amended soil. Space the holes 3 feet apart. If the temperatures are still dropping below 65 degrees Fahrenheit, hold off on transplanting until the weather warms up.
Slide the seedlings out their pots, place one lemon grass seedling in each hole and fill in the extra room with soil. Press down on the soil with the flat of your hand to secure the seedlings. Water the area until the soil is damp to a depth of 2 inches.
Water every few days, especially during hot, dry weather. Use a misting setting and allow the water to seep at least 1 inch into the soil at each watering. Fertilize once a month with a balanced 10-10-10 fertilizer.