Light:
Set your citrus tree in full sun from a southern exposure. Trees need lots of light. If that’s not possible, supplement the light by installing 40-watt fluorescent shop lights above the plants. This is especially important in the winter, when they need 12 hours of light.
Water:
You’ll need to keep the soil evenly moist and since most interiors are quite dry, mist your plant often (daily if you can). Give your citrus tree a shower occasionally. (They love to be wiped down gently with a sponge.)
Temperature:
Citrus plants thrive in a normal temperature range of 20ºC during day to 12ºC at night. Though the plants are evergreen, they will go into dormancy and stop growing below 12ºC.
Fertilizer:
Like most house plants, citrus prefer a slightly acid, all-purpose mix, which you can get by using a peat-moss based growing mix.
Pollination:
When you grow plants indoors, bees and insects can’t pollinate them. So you need to use a paintbrush or cotton swab to rub pollen within the flower. Sometimes they will produce fruit without doing this, but it’s a good idea to increase your chances!