Citrus is found in oranges, lemons, grapefruit, limes and other citrus fruits. Citrus fruits grown on evergreen shrubs and trees. They can be grown as fruiting plants in the heated greenhouse although the may be moved outside in the warmest months in southern counties. The most cold tolerant citrus are kumquats.
Plants grown for their fruit do best in a humid greenhouse or conservatory. Centrally heated rooms lack humidity and can stress citrus, so they are unlikely to flower or fruit in these conditions.
Temperatures below 7°C (45°F) may cause damage to the plants. A minimum winter night temperature of 10°C (50°F) is fine for lemons, while kumquats will tolerate winter temperatures down to 7°C (45°F).
Juvenile citrus plants are popular house plants. C.limonia and C.taitensis should be grown in an ordinary potting compost and put out of doors in summer in good weather to harden the wood. Citrus need a bright sunny position. Most will only reach 3–5ft tall when container-grown but can grow larger in good conditions.