How to Grow Indoor Citrus

There's nothing more enchanting than the perfume of citrus blossoms in late winter. Growing citrus indoors can be daunting, but the effort is well worth it for the aromatic flowers and foliage—and the much-anticipated fruit. So when seasonal temperatures consistently dip below 50°F, bring your potted citrus plants indoors. Your citrus plants will flourish in a sunny space until the weather warms up. Watch out for root rot from overwatering or annoying pests.

Watering Indoor Citrus Trees

Overwatering is the number one killer of citrus. The soil needs to dry out between deep waterings: A moisture meter ($15, The Home Depot) should read three fully inserted in the soil. When your plant needs more hydration, drench its soil until water runs from the pot's drainage hole. Suction up any water in the saucer with a turkey baster to prevent a soggy bottom and root rot.

Dropping green leaves and dying twigs are root rot symptoms (due to overwatering). If you suspect this problem, you'll need to intervene.

1. Put the tree on its side.
2. Pull the tree gently from the pot, including the soil. If roots disintegrate, they've rotted.
3. Immediately remove soil and damaged roots, wash the pot well with soap and water, and replant in fresh potting mix.
4. Water, then allow the soil to dry out before watering again.

New growth will appear in a few months if the process goes well. If not, it's probably time to toss out your plant.

Best Pots for Indoor Citrus Trees

Don't use a pot that's too big because the soil will stay damp too long, and dampness can be deadly to plants when you're growing citrus indoors (avoid self-watering containers for the same reason). If you want to repot your tree from its nursery container, only go up to two inches wider. Always make sure the container you do use has a drainage hole. I like to use a 1:1 mix of citrus potting soil ($20, Etsy) and orchid bark (from $6, Etsy) to help water drain extra well.

Lighting and Fertilizer Needs

Place your citrus tree in the sunniest spot possible. South-, east- and west-facing windows are ideal. Use grow lights if you lack bright natural light, but make sure to turn them off at night. These trees didn't evolve with constant sunshine and need rest.

As long as your tree is healthy, feed it monthly with organic granular citrus fertilizer. Feeding a sick tree may exacerbate many problems. Follow the dosage instructions for the pot size to the letter.

Keep an Eye on Climate

Avoid exposing your plant to hot or cold blasts of air. Never place it beside a heat source or near an exterior door. In warm weather, citrus trees prefer life outside. If you don't have outdoor space and have the right conditions indoors, you can keep them thriving year-round if you're hypervigilant about care.

Best Options for Growing Citrus Indoors

Thai lime, finger lime, and Meyer lemon are good choices for growing citrus indoors. Thai lime can thrive in bright, indirect light. It has fragrant leaves you can cook with and fruit that makes delicious marmalade. Finger lime fruits are entirely filled with round vesicles called citrus caviar. When it's grafted onto dwarf rootstock, the petite, fuss-free trees can live on a small table. Meyer lemon needs tons of light and is highly sensitive to overwatering, but the flowers are worth the extra attention. I like preserving the thin-skinned fruit in salt. (Editor's note: try this Meyer lemon pie for something sweet.)

How to Control Citrus Pests

Check leaves daily for bugs. Common pests include spider mites and scale. The mites are so tiny they are hard to spot, so look for their more visible cobwebs, especially on the backs of leaves. Sticky spots, aka honeydew, on leaves or on the floor under the tree branches are often the first clue that your plant has scale. These insects can look like flat brown ovals or fluffy white creatures.

To remove both of these pests:

1. Spray the entire tree with a solution of one tablespoon of liquid dish soap mixed with a quart of water.
2. Wash every leaf and branch with a soft sponge, using a toothbrush in nooks and crannies.
3. Rinse off the tree in the shower (cover the soil with a plastic bag taped around the trunk) or with a spray bottle.

If you see pests flying around your citrus tree, they're most likely fungus gnats (a sign of overwatering). The winged adults are annoying but harmless to plants, but the larvae can damage roots. Diatomaceous earth sprinkled in the pot controls both adults and larvae. And you'll also want to cut back on watering.