The plant: The next time you dine in a Thai restaurant, you’ll likely enjoy dishes made with Thai lime. It may surprise you to learn that it’s not the fruit with its bumpy, wrinkled rind that’s used; it’s the deeply green, glossy leaves that impart piquant flavor to many Thai dishes.
In the countryside of tropical Thailand, it’s not uncommon to find one of these trees growing in a homeowner’s yard. This prized ingredient, also known also as the Kaffir or porcupine lime, has been used by generations of Thai and other Southeast Asian cooks to prepare curries, stews, soups and stir-fries. Adding fine slivers of Thai lime leaves to a dish can create a splendid balance of flavor and texture. In the garden, you can choose to plant it in the ground or in a large container. Even if you don’t cook, you can enjoy the fragrant citrus scent when you snap a crisp leaf in half. Aromatherapists recommend the pure essential oil of Thai lime to bring you a sense of clarity, openness and balance.
Growing guide: Full sun
Culture: Select a spot protected from the hottest western sun in summer and from extreme cold spots in winter. Thai lime is evergreen and can grow 8 to 10 feet tall. In the low desert, March and April are the best months for planting citrus. Dig a hole two to three times the width of your young tree’s container. Rough up the sides of the hole to encourage outward root growth. Set the top of the root ball 1 to 2 inches above ground level, making sure the bud union remains above the ground. Combine backfill soil with about one-fifth compost. Fill in around the root ball, and water the soil mixture so it settles. Next, create an inner berm around the trunk about 6 to 12 inches from the base of the tree, to keep standing water from touching the bark during irrigation. Then form an outer water basin by making a 2-inch mound of soil ringing the inner berm and about a foot beyond the young tree’s drip line. Now fill the ring you’ve created with water, and again allow it to sink in. Use this irrigation basin each time you water, and increase the width of the irrigation ring about once a year for six to eight years to ensure that the outermost roots of the tree are being irrigated. Keep in mind that these roots usually extend at least 1 to 2 feet beyond the tree’s drip line. Thai lime blooms most heavily in April and takes about 10 months to produce mature fruit. Be prepared for the Thai lime tree’s sharp thorns, and take care to avoid being scratched.
Maintenance: Newly planted trees should be deeply watered (see above) every two to three days during the month after planting to help establish a strong root system. Water should penetrate to a depth of at least 18 inches during the first year of planting. Thereafter, water every 5 to 7 days through summer, and about every 14 days in winter. The depth of water penetration should increase up to 36 inches deep by the time the tree has been in the ground three years. Newly planted citrus doesn’t need to be fertilized for a year. Once established, your tree will need fertilizer with a good nitrogen source. Tropica Mango Rare & Exotic Fruit Nursery recommends a feeding schedule similar to other citrus, with fertilizer applied three times a year in February, May, and September. Be careful not to overfertilize, since that could burn the tree’s roots. Organic sources include chicken manure crumbles, cottonseed meal, kelp meal or liquid seaweed. Layer several inches of mulch (compost, wood chips, straw or dried leaves) around the base of the tree, but several inches away from the trunk. Apply mulch each year to protect shallow-growing roots. Remove any growth below the bud union. The tree does not require pruning, but you can trim off any dead wood in late February to early March, when danger of frost has passed.
Barn Goddess tips: Not ready to cook with the leaves? Why not “go green” by tossing the bleach aside and using the juice from a Thai lime blended with a sprinkling of detergent to effectively remove stubborn stains? On the body, Thai lime shampoo will invigorate the scalp and purify hair. A single Thai lime tree can supply enough limes to keep your house and family clean all year. Transplants are usually available year-round, though the plants are relatively rare and availability may be sporadic. Check for availability at Tropica Mango Rare & Exotic Fruit Nursery or other local nurseries.