How do I care for my citron plant indoors?
Basically the citron (Citrus medica) requires treatment like its citrus relatives.
Grown indoors in pots, many will produce fruit when grown under the correct conditions. Key elements for success are good light, adequate humidity in the winter, well-drained potting soil, additional nutrients and consistent watering.
These plants need full sun--at least 6 hours a day of direct sunlight. If you don’t have a south-facing window, full-spectrum fluorescent lights can be used as a supplement but for significantly longer hours of use than natural light.
These plants need high humidity--the humidity level in most houses in the winter is too low for ideal citrus culture. It is helpful to spray the trees frequently, or even better, to use a room humidifier. You can also stand the pot on tray of damp pebbles or moist peat moss. You can fill a larger tray, fill it with gravel type pebbles, available from nurseries, and keep water half-way up. A small amount of charcoal from aquarium store will help to keep it clean. (A dry,hot environment attracts mites.)
Citrus grow best between 55°F to 85°F. It can tolerate 40°F, but stops growing actively below 50°. It's best to water actively growing plants moderately, allowing the top inch of the mixture to dry out between thorough waterings. In any resting period, water only enough to keep the mixture from completely drying out.
Finally, apply a liquid 20-20-20 fertilizer at half-strength during the summer months.
Hope this is helpful.
Courtesy of NYBG Plant Information Services