Lemongrass is a tender perennial native to Malaysia. The herb exudes a mild lemony fragrance and lends a lemon-citrus flavor to poultry and fish dishes. Lemongrass is a common ingredient in Asian cooking, and fresh stalks are typically readily available from Asian markets in the United States. This plant germinates well from seeds, but there's really no reason to wait that long for your own delicious herbs to sprout and grow into mature plants. They'll root happily from the stalks that you usually purchase for cooking.
Look for the freshest bunches of lemongrass you can find. The long green stalks are tough cylinders that have tufts of several thick leaves at their tops. The stalks terminate with slightly enlarged white bulbs, making lemongrass look rather like a bunch of scallions. Occasionally a stalk with one or more intact roots will have slipped past quality control, and that gives you the bonus of a plant with a head start.
Use a clean, sharp knife to trim the bottom tips from several lemongrass stalks, which will probably be a bit dry and callused. Peel off any outer membranes that appear dry or shriveled. Discard these materials.
Trim the foliage off down to the tough parts of the stalks to use for cooking. If you'll put the leaves in an airtight container, they'll keep in the refrigerator for up to a week.
Put the lemongrass stalks in a clear glass with a couple of inches of water in it. Place the glass near a warm, sunny window. Roots will form in about 1 to 3 weeks. Replace water to the original level as it evaporates.
Plant the lemongrass stalks in individual well-draining pots about 2 or 3 weeks after rooting begins. Use a light, premium potting soil that contains Perlite to facilitate moisture retention. Position the stalk so the uppermost roots are barely covered with soil.
Set the lemongrass in a warm spot near a bright window where it will receive at least six hours of full sun daily. Protect your warm climate native from drafts and freezing temperatures.
Water this plant thoroughly to evenly moisten the soil, but not so much that it's soggy. Lemongrass doesn't like wet feet. Don't water again until the soil surface feels dry to the touch. If the plant begins to wilt, water thoroughly right away.
Feed your indoor lemongrass a good all-purpose fertilizer once yearly in the spring when new growth begins. Follow the packaging instructions carefully.
Trim leaves freely for culinary use throughout the growing season once the plant has produced more than three stalks. The more you harvest this plant, the longer it will be before re-potting is necessary. Step it up a pot size when it multiplies to the point of being overcrowded.