Lemon grass is an exotic ingredient used in Thai and other Southeast Asian cuisine. It is expensive to purchase in the shops but it is easy to grow at home. Switch from shop-bought stalks to your own gourmet garden Thai experience.
Purchase several lemongrass stalks from your local supermarket or speciality foods shop. Choose the plumpest, freshest looking lemongrass stalks that you can find. Stalks with tiny root nubs or actual sprouted roots are best if you can find them. For a 25 cm (10 inch) pot, purchase 10 stalks. Not all stalks are likely to root and this will give you enough to plant.
Prepare the lemongrass shoots. Cut off the top of the stalks 10 cm (4 inches) from the root end. You can use the discarded stalks and leaves for cooking or for teas. If you do not need them right away, you can freeze for future dishes. Place the lemongrass shoots in a glass of water, so that the roots and at least 2.5 cm (1 inch) of the stem is covered with water. If you are using tap water, allow the water to sit out on the worktop for at least an hour prior to adding the lemongrass shoots in order to dissipate the chlorine and other chemicals. Set the stalks in a sunny window.
Plant the lemongrass shoots. Within a week or two, you will see new root growth. When the roots are about 2.5 cm (1 inch) long, fill the pot with potting soil or compost and gently plant the lemongrass shoots, taking care to not snap off the new tender roots. The lemongrass shoots should be planted 2.5 cm (1 inch) deep in the soil. Tamp the soil around the roots carefully but firmly. Water the lemongrass shoots thoroughly.
Place the lemongrass shoots in a sunny window if the outside temperature is less than 15.6 degrees Celsius (60 degrees Fahrenheit) or outdoors in full sun if the temperature is above that. Cover with a blanket if frost threatens. Lemongrass will grow to approximately 1.2 to 1.8 m (4 to 6 feet) high and a clump can spread 1.8 to 2.4 m (6 to 8 feet) wide, so give the lemongrass room to spread.
Harvest the lemongrass. Leaves for salads or tea can be snipped at any time once the plants become established. To harvest a stalk, find the largest and plumpest stalk and gently tug it from the ground, being careful to not disturb the surrounding stalks. Cut the stalk to 20 cm (8 inches) long. Chop and freeze the leaves if desired for future uses. Remove the tough outer skin of the stalk and either chop or bruise the fragrant inner section, depending on the type of dish being made.
Propagate the lemongrass. In the second year, divide the clump of lemon grass. If potted, carefully remove the entire root ball from the pot, then separate the clump gently by hand into three or four sections. Replant each section in its own pot, water thoroughly and care for as the original clump. If the lemongrass is in the ground, carefully dig up the root ball with a spade and separate into sections. Replant the sections at least 1.2 m (4 feet) away from each other to allow room for spreading.
Don't over-fertilise lemongrass, as it was originally a wild grass and can usually survive in even sand or clay.