How to Care for Indoor Citrus Plants

Plant deep. A wide and deep container, either terra cotta or plastic. Citrus roots are fairly deep, so you'll need a fairly tall pot.

Use an all-purpose potting mix. It's nice if it's slightly acidic, and you can sometimes find potting mixes especially made for citrus.

Give your tree chilly nights. "The temperature during the day is not a big deal," says Paul. "However, at night, citrus likes to be chilly, kind of like me and you." A temperature between 50 to 55 degrees is ideal.

Provide as much light as possible. "This is a big problem for a lot of people," he says. "Place in a south or southeast-facing window. If you don't have enough light, you can always add fluorescent or spotlights with full-spectrum lights." With modern insulated windows, put the plant pretty close to the window. If the window isn't insulated, back off a foot or two.

Maintain an evenly moist soil. Don't treat citrus like other plants — that is, letting it dry out between waterings. Instead, keep it moist. "During the winter, however, don't over water, or you'll get root rot, which is fairly common. When the soil is dry an inch below the surface, add water." Don't let water sit in the saucer below the container.

Keep the humidity high. Citrus requires a humidity of 50 to 60 percent. Most households, however, measure only 20 percent during the winter. "Misting daily is very important, and few people do that. Try to get in the habit of it. Maybe if you're fixing dinner, take a break and give it a spray." Group plants together to make it easier to keep humidity elevated, and set saucers of water around the plants.

Watch for pests. The most likely are whiteflies and spider mites. "Insecticidal soap controls virtually all the pests for houseplants and it's non-toxic."

Fertilize lightly. "You have to be careful when fertilizing in winter," he says. "The citrus will have a slow growth rate anyway, so I'd suggest maybe once a month with a weak liquid fertilizer, diluted from a quarter to a third of what the manufacturer recommends." Paul uses organic products such as seaweed extract.

Prune lightly when necessary. "If it's a little straggly or misshapen, you can cut all the way back to the main branch, or you can do just a little pinching to make it bushier."

Pretend you're a bee. When Mother Nature isn't close at hand, you have to step in. To set fruit indoors, you'll have to hand pollinate these plants, says Paul. "Take a paintbrush, push it into a flower and move it onto the next flower, and so on and so on and so on."

If your tree hasn't bloomed yet, don't panic. You have to wait four to five years before your citrus blooms, unless you already have a mature plant.

Limequats

Suggested varieties

Some citrus works better indoors than others. You'll have the best luck with dwarf plants that have been bred for container gardening, and if you select from these varieties:

Meyer lemon
lime
sour orange
grapefruit
kumquat
mandarin
limequat