Kaffir Lime Trees grow best in a sunny greenhouse, conservatory or on a windowsill at a minimum temperature of 5ºC (40ºF). It is beneficial to stand the plant outdoors in a sunny, sheltered spot during hot summer weather. Indoors place the plant away from radiators and draughts. In a dry atmosphere or low light conditions leaf drop can occur, misting with water will help to increase the humidity around the plant. A citrus tree can lose all its foliage but it will recover and under ideal conditions will start to produce new shoots within a few weeks. While the tree is leafless take extra special care to avoid overwatering the plant.
Water thoroughly each time the surface of the compost becomes dry. In winter water the plants well and allow the compost to dry out before watering again. In the summer months watering may be daily during hot weather and fortnightly during the cool winter months. Do not allow the compost to become soggy and waterlogged as this will kill the roots. Feeding the regularly with a Summer or Winter Fertiliser as appropriate. Citrus do not thrive with high salt levels in the compost so taking the plant outside twice a year and drenching with lots of clean water will prevent any build-up of excess fertiliser salts. To encourage a bushy habit and to maintain a good shape, plants can be trimmed in late winter or early spring just as the new growth starts to sprout in the spring.
The older, darker leaves are used as a flavouring in Asian cuisine. Fresh young leaves can be added to salads. The leaves can be stored for later use by drying or freezing. Mature trees will produce a small, knobbly fruit. The grated peel can also be used as a flavouring, the juice is seldom used as it is too acidic.