How to Care for a Lemon Tree

Creating the Ideal Environment

Keep your tree outdoors if you live in a warm, temperate climate. As long as your nighttime temperatures don’t drop below 41 °F (5 °C), keep your lemon tree outdoors in a pot. If and when the weather does turn inclement, bring the tree indoors to keep it safe. If you live in an area that experiences at least 8 hours of sunlight daily year-round and that never drops below 41 to 44 °F (5 to 7 °C), you can plant your lemon tree outdoors in the ground.Did You Know? Lemons thrive in outdoor groves in areas like India, Italy, California, and Florida.

Grow your lemon tree indoors during the colder months. Once temperatures begin dropping and frost starts appearing on the ground, bring your lemon tree indoors to a sunroom, a patio, a greenhouse, or some other room that will still allow it to receive abundant sunlight. Frost will kill a lemon tree, so pay close attention to the weather forecast to ensure you bring it indoors in time. Dwarf lemon trees are a great variety to grow if you’ll be bringing your tree indoors. They produce a lot of fruit, but they won’t get so big that it would be impossible to move them. At the most, they’ll grow to be 5 to 7 feet (1.5 to 2.1 m) tall, but you can keep them trimmed back to a smaller size if you want.

Maintain an ideal temperature of 50 to 70 °F (10 to 21 °C). During the summer months, it’s okay if the trees are in temperatures higher than 70 °F (21 °C) during the day because they’ll experience cooler temperatures at night. If the tree is kept inside, keep an eye on the temperature to make sure it doesn’t drop too low or rise too high. Especially during the winter months when the air can be drier, it’s important to make sure the tree doesn’t get too hot. For especially dry climates, use a humidifier when your tree is indoors to keep the climate at the right level, around 50% humidity. If you live in a climate where your tree can grow outdoors, there’s no need to worry about the humidity level.

Make sure your tree gets at least 6 to 8 hours of sunlight every day. Place your lemon tree in a location where it will get direct sunlight. Avoid putting it somewhere where it’ll be blocked from the sun by other plants. Depending on the time of year, move the tree around your yard or patio so it gets the maximum exposure possible. If your tree is indoors, you may want to move it from season to season to make sure it’s always getting the maximum amount of light possible. If you live in a climate that experiences a lot of cloudy, dark weather, invest in a grow light. You can buy one online or from your local nursery.

Keep your tree away from radiators and heat sources. When the lemon tree is inside, make sure it’s not next to a heat source, as it could dry out the leaves and the soil. While natural heat and sunlight are good for the tree, excessively dry heat will hurt it. If possible, keep the tree in a room with a ceiling fan or put a standing fan in the room. Circulating air will help keep the tree healthy. Keep the fan on for as many hours a day as you can.

Fertilizing and Watering the Tree

Select a well-draining pot that is 25% bigger than the lemon-tree bulb. The bulb consists of the roots and the clumped dirt that is attached to them. If you buy your tree from a nursery, it may already be in an appropriately sized container—just ask the sales associate to make sure. If you do need to re-pot it, look for a 5 US gal (19 L) pot for a 2 to 3 year-old tree or a 10 US gal (38 L) pot for trees older than that. A pot bigger than 15 US gal (57 L) will be really hard to move around.

Use well-draining, composted soil to cover the bulb of the tree. Pick sandy or loamy soil for an option that drains well. Avoid using soil made with clay or that has heavy alkaline levels. Cover the bulbed part of the tree (the roots and the dirt attached to the roots), but stop when you get to the base of the roots. Lemon trees are pretty hardy and can grow in many different types of soil, though the loamy soil is the preferred type. If you want to test the pH level, aim for a reading between 5.5 and 6.5 for optimal growth. If the soil is too acidic, you could add a base like compost or manure to the soil. If the soil isn’t acidic enough, add a compound made of powdered limestone.

Fertilize the soil surface only so you don’t disturb the roots of the tree. Fertilize the tree every 1 to 2 months during the spring and summer and every 2 to 3 months during the fall and winter. Use a citrus-specific fertilizer, and only apply it to the top of the soil; don’t mix it in with the rest of the soil. Spring and summer are the active-growing months; fall and winter are the dormant months.

Water your lemon tree every 10 to 14 days. Water the tree while slowly counting to 20. Stop once you notice water starting to come out of the bottom of the pot; if after 20 seconds you still don’t see water coming out of the pot, continue counting and watering for an additional 10 seconds. If your climate is particularly dry, keep an eye on the soil and the leaves of the tree. If the soil is dry to the touch or if the leaves are drooping, water the tree. During the hottest months, you may need to water it once or twice a week. Don't water the tree until at least the top 2 in (5.1 cm) of the soil is dry.

Keep your tree in a location where it won’t be sitting in water. While lemon trees need a lot of water, they also shouldn’t be left to sit in water. If the pot is outside, place it somewhere that rainwater will flow away from it rather than to it, like on a garden wall or on the highest point of an incline. If your area is experiencing really heavy rains, you may want to bring your lemon tree indoors or put it under an awning until the rain passes.

Harvesting and Pruning

Pick lemons once they are firm and 2 to 3 inches (5.1 to 7.6 cm) in size. Pick very green lemons if you prefer a more sour fruit; the yellower it gets, the sweeter it will be. Lemons will continue to ripen even after they’ve been plucked from the tree. The lemons may still be green when they reach the correct size, and this is okay. The size is actually more important than the shade of the fruit. A squishy lemon has been left on the branch too long.

Twist the fruit gently until it breaks off of the branch. Grab the lemon firmly in one hand and twist it around on the branch. It should snap off fairly easily. If you prefer, you could also use a clean pair of gardening shears to cut the lemon from the tree. Avoid pulling the lemon off, as this could damage the branch or even detach it completely from the tree.Did You Know? Lemons can be used for much more than additions to drinks and foods! Run them through the garbage disposal to deodorize your sink; rub them on kitchen and bathroom faucets to make them shine; apply lemon juice to acne and blackheads to help them clear up.

Prune your lemon tree from March to May so it stays healthy. The best time to prune your tree is after most of the lemons have been harvested but before the new buds begin to bloom. Depending on your climate, prune sometime between late winter and early spring. Pruning is essential to keeping the tree healthy and promoting new growth.

Use clean shears to trim each new shoot down to half its original length. Cut the branch at a 45-degree angle and never cut it back all the way to the main trunk. Focus on pruning the longest and gangliest of the branches and leave the thicker, more established branches alone. Trim back all low-hanging, downward-facing branches that are reaching toward the soil. Also take time to pluck away dead leaves from the branches and remove fallen ones from the soil whenever you notice them.

Keep an eye out for pests to treat any problems that arise. Keeping your lemon tree pruned is a great first step to preventing unwanted pests from making their home in your tree. If you notice spider mites or aphids, use a hose to knock them off of the tree (do this outdoors). If problems persist, or if there are other pests on the plant, you can use an insecticide or horticultural oil to help protect your tree—just make sure to ask a professional and follow instructions so you don’t accidentally harm your lemon tree. Some of the more common pests are: Red mites: small, red insects that eat leaves and twigs on citrus plants Spider mites: small, white insects that are more common in cooler climates Citrus mealybugs: Small, flat, oval, and wingless, these creatures are covered with a wax-like substance that looks puffy Citrus whiteflies: small, white, winged insects that appear on the underside of citrus leaves