If you live in a cold climate that is not conducive to growing citrus trees, you can easily grow a lemon tree indoors. Lemon trees are also one of the easiest citrus trees to pollinate manually, making it easier to get the tree to produce fruit indoors. Your success in growing a lemon tree inside will depend on the right amounts of light, warmth and water, as well as the correct fertilizer and potting soil. With a little bit of care, you can enjoy fresh-grown lemons in your home.
Purchase a healthy lemon tree that is 2 to 3 years old and is suitable for indoor growing. Meyer lemon trees are the best variety to grow inside. If the store-bought lemon tree is in a container containing a soilless medium, rinse off enough of the medium so that the peripheral roots are exposed. Use a gentle stream of water from a garden hose to do this.
Prepare a 10-gallon planter pot for your lemon tree. Make sure the pot has drainage holes in the bottom. Line the bottom with gravel, and then add a peat moss-based growing mix. The soil you use should be slightly acidic.
Place the lemon tree into the planter pot and cover the root ball with an inch of the potting mix so that the trunk is not below the soil line. Water the soil to help it settle around the roots and eliminate any air pockets.
Place your lemon tree next to a large window that receives full sun, preferably from a southern exposure. Make sure the tree gets five to six hours of full sunlight each day. If you can't provide enough natural light, set up 40-watt fluorescent grow lights above the lemon tree.
Maintain a temperature around 70 degrees F during the day and at least 55 degrees F at night. Lemon trees become dormant below 54 degrees F.
Water your lemon tree every two to three days, giving it a shower of water occasionally. Mist the leaves at least once a week during most of the year. In winter when your house is drier, mist daily and place pebbles or gravel in the drip tray beneath the planter, then fill the tray with 1 inch of water to create more humidity.
Fertilize your lemon tree using a nitrogen-rich fertilizer each time you water. A 20-10-10 fertilizer works great. Feed the lemon tree only during its growing seasons in late winter, June and August. Follow the dosage instructions on the packaging.