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.
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.)
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.
Like most house plants, citrus prefer a slightly acid, all-purpose mix, which you can get by using a peat-moss based growing mix.
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!