To obtain seeds from the lumpy fruit, select the ripest Kaffir limes. The fruits turn yellow when completely ripe. If Kaffir limes aren’t available at the local grocery store, check the farmers’ markets and online for fresh fruits or seeds. The seeds are removed from the fruit and planted immediately. Unlike many fruit tree seeds, Kaffir lime seeds don’t require stratification to sprout.
Kaffir lime seeds germinate in 12 to 15 days when kept warm and moist. Many gardeners cover the flowerpot with plastic wrap to help maintain the humidity level necessary to sprout this subtropical tree. Once the seedlings appear, the plastic is removed. Placing the flowerpot on a tray filled with pebbles and water helps keep the humidity high enough for the Kaffir lime tree to thrive.
The pungent leaves of the Kaffir lime (Citrus hystrix) fill the garden air with a distinctive scent unlike other citrus trees. The thorn-filled, shrubby trees thrive in a sunny, sheltered corner of the garden. Used in Cambodian and Thai cooking, the flavorful leaves are sliced or shredded into curries and soups. Also known as the wild lime, Kieffer lime or Thai lime, Kaffir lime trees are hardy in U.S. Department of Agriculture plant hardiness zones 9 and 10.
While commercial growers generally start seeds in the spring, if you’re growing the Kaffir lime as a houseplant, you can start seeds any time of the year. Simply bury the fresh seeds in moist potting soil, planting them 1/2 to 3/4 inch deep. Placing the flowerpot in a brightly lit location where the temperature remains between 70 and 80 degrees Fahrenheit speeds the seeds’ germination.
The Kaffir lime requires bright light and warmth to thrive in the garden or sunroom. The Kaffir lime tree is often planted in the garden in mild Mediterranean climates. It requires a well-draining soil in a sunny, sheltered location where you can protect it from frost. The soil must be kept moist at all times; never let the tree dry out. Indoor trees are fertilized monthly, while outdoor trees are generally fertilized in the spring. Most gardeners prune only to shape the tree, carefully avoiding the sharp thorns on the trunk and branches. A tree planted from a seed may take up to 10 years to produce fruits.
11/9/1987, EMN: Fruit compared with CRC 450 (Wilder), 2315 (Page), 391 (Tahiti) and seems to be identical with all these, and probably identical to Ponds (CRC 449) but Ponds was somewhat rougher at this picking.