How to grow lemon trees indoors

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In different cultures, lemon trees symbolize the goodness of life: love, light and happiness, to name a few. They make wonderful holiday or housewarming gifts or memorial plants to celebrate special occasions. Whether you buy a lemon tree for yourself or get one as a gift, it provides an excellent, long-lived indoor plant that offers attractive foliage, fragrant flowers and sour fruit for appeal all year round.

It is easy to grow a lemon tree indoors, but it requires a bit of specialized care in terms of light and fertilizer. Read on to learn how to grow a lemon tree indoors.

Indoor lemon tree care in an instant

Common name: Lemon
Scientific name: Citrus lemon
Land: Well drained, pH 5.5 to 6.5
Light: Bright
Water: Medium
Food: Balanced organic or slow-release formula
Temperature and humidity: 65 to 75 degrees Fahrenheit, 50 percent humidity
Propagation: Messy cuttings, grafting
Security: Thorns, allergenic to some, non-toxic to humans, somewhat toxic to pets

Properties of the lemon tree

The lemon tree grows in semi-tropical areas of USDA hardiness zones 9 through 11, but it can also be an excellent indoor plant in cool areas. It is a relatively easy plant that prefers to spend the summer outdoors. Lemon trees require little pruning, moderate watering and a consistent supply of nitrogen-rich plant food. Their most vital growth requirements are without a doubt bright light and good air circulation.

Cool temperatures overnight help stimulate flowering, especially in winter and early spring. Like other citrus trees, lemons produce small white fragrant flowers. They are mostly self-fertile, so a single tree can offer high fruit yields with patience. Ripening can take up to a year before the lemons are ready to harvest.

The leaves of the lemon tree appear with a reddish hue and develop to deep green above and lighter at the bottom. The flowers are kept singly, in pairs or in small clusters, and the aromatic fruits are dotted with oil glands that produce a lemon-like scent as they ripen.

Although lemon trees can grow to 20 feet or higher when planted outdoors, they do quality tests in containers where they typically reach half that height. This makes them an exquisite gift for plant lovers. Lemon trees that are pruned and repotted every few years retain a shrub shape about 5 to 7 feet tall.

Related: 20 smart household uses for lemons

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Types of indoor lemon trees

  • Dwarf Improved Meyer Lemon is a cross between a lemon and a mandarin that produces small, rounded yellow fruits with a semi-sweet taste.
  • Dwarf Ponderosa Lemon is a cross between a lemon and a lemon that bears large, traditional lemon fruits.
  • Dwarf variegated pink lemon has green and yellow variegated fruit with deep pink flesh and clear juice.
  • Dwarf Lisbon Lemon is a vigorous tree that produces an abundance of juicy, flavorful thin-skinned fruits.

Choice of soil for lemon trees

Lemon trees grow best in rich, well-drained soil with a pH between 5.5 and 6.5. High-quality indoor-outdoor container mixes should suffice. Apply fertilizer specifically referred to as “citrus food” to help maintain the correct pH.

Lemon trees in pots require both a suitable size container and the right kind of potting mix to thrive. When you repot, the pot sizes increase step by step. For example, a new lemon tree in a 3-gallon (10-inch diameter) pot should be transplanted into a 12-inch pot. Do not go too big at once, otherwise the risk of root rot increases. A 16- to 20-inch container will be the right size for a permanent home.

The right light

Good flower and fruit production requires full sun exposure, which ranges from difficult to impossible in some homes. Most gardeners find success by moving lemon trees to a sunny spot outdoors during the growing season and back to a bright room indoors on cold nights.

In the spring, transplant lemon trees into a larger pot if more growth space is needed. When the danger of frost is over, first move the tree to a strongly filtered light outdoors. Gradually increase the duration of direct sun exposure daily over 2 weeks. If cold weather is in the forecast, move the tree back to a bright room – preferably one with large south-facing windows.

Related: These are the most popular houseplants in America

Watering of lemon trees

Water the plant deeply when the soil dries out to a depth of 2 inches. Examine the ground with a stick or quarter inch dowel bar marked with a 2-inch depth indicator. Let the dowel lie in the ground for 1 minute. Then pull it out and look at the lower end. If there is clear moisture at the bottom of the dowel, do not water the wood. If the dowel seems dry, soak the soil thoroughly and allow excess water to drain freely. Do not leave water in a plate under the tree.

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Fertilization of indoor lemon trees

For healthy plant growth and fruiting, lemon trees benefit from consistent feeding throughout the year. Choose fertilizers specially formulated for citrus plants to help maintain a slightly acidic pH. A balanced fertilizer, such as 8-8-8, is best.

During the spring and summer growing season, apply granular organic fertilizer every 6 to 8 weeks; or apply slow-release fertilizer once in the spring and supplement it with liquid plant food every half week. At the end of the growing season, granular organic plant feed or another application of slow-release fertilizer is applied to add nutrients throughout the winter. Do not use liquid fertilizer in the winter.

Setting of temperature and humidity

An indoor lemon tree will thrive under average home climate conditions. A temperature between 65 and 75 degrees Fahrenheit and humidity around 50 percent work well for overwintering. However, be careful when moving the tree outdoors in the spring. An acclimatized lemon tree can be bumped by cool temperatures below 50 degrees and it will be damaged by frost. It is best to keep the tree indoors in the spring until all danger of frost is over and the night temperatures remain above 50 degrees Fahrenheit.

Summer sun and heat are no problem for potted lemon trees after a gradual transition period. At the height of summer, they can withstand high temperatures in the 90s, as long as they are consistently watered well. The irrigation frequency should be increased in hot weather.

Propagation of lemon trees

Lemonade enthusiasts often wonder how to grow a lemon tree from a seed, but that’s not how it is done. Seed-grown fruit is extremely unpredictable in quality, taste and even tree characteristics. Professional growers and retail nurseries mostly sell grafted lemon trees.

To save breeding time and space and to ensure identical genetics, nurseries fuse branch cuttings from one kind of plant with root cuttings from another. Anything that grows over the graft association will exhibit the desired property, but if any shoots emerge from under the graft, they must be removed and discarded.

Instead of growing a lemon tree from seed, home gardeners can grow lemon trees either from rooted cuttings or by grafting. The easiest way to propagate the fruit tree is by taking a 6- to 8-inch branch from a stem with at least four side buds and no flowers or fruit in late spring, making sure:

  • Remove leaves from the lower 4 inches of the stem
  • Dip the bottom of the cuttings into root hormone
  • Put the cuttings in a 4-inch pot filled with pre-moistened potting soil
  • Place the cutting in a warm, well-lit place and keep the soil moist but not moist

The cuttings should grow roots within a month. Use this method to grow new lemon trees on their own roots or to produce rootstock of three-leaved citrus fruits for grafting. To graft new citrus trees, this T-budding method ensures a high success rate. Those in citrus-growing regions should follow local management to avoid the spread of disease.

Related: 14 Symptoms of an Unhappy Houseplant (and How to Treat Them)

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Safety considerations

Of course, if someone in a home has a citrus allergy, avoid growing a lemon tree indoors. The primary symptom of citrus allergy is contact dermatitis, an itchy rash that resembles poison ivy. Otherwise, lemon trees are considered safe and non-toxic to humans. Essential oils most commonly found in the fruits, however, are toxic to animals, so those with curious pets should exercise caution.

Some lemon varieties are thorny, and others are grafted onto the rootstock, which can send thorny shoots up. Beware of these stickers, and be sure to prune any shoots that come down from the graft union.

Potential pests and diseases

Lemon trees are susceptible to mellus, spider mites and dandruff insects. These are generally avoided with favorable growth conditions such as good sun exposure, air circulation, proper fertilization and consistent watering. If insect problems occur, treat them immediately by picking insects by hand or pruning the affected area if it is small. Quarantine the tree and spray with an appropriate insecticide if necessary.

Aphid feeding can spread a fungal disease called tristeza, indicated by yellowing of leaves and rapid decline. Infected lemon trees can succumb to root rot. Always watch for insects and treat them when they appear. Under cool, humid conditions, the fungus Botrytis causes cloudy gray mold-like growth to occur on stems and flowers. Keep lemon trees in a bright, sunny place, and as they mature, prune dense branches to improve air circulation.

Frequently asked questions about caring for indoor lemon trees

If you are considering adding a lemon tree to your houseplant collection, the following frequently asked questions can help clarify any lingering questions.

Q. Do lemon trees grow well in pots?

Yes, lemon trees grow well in pots. Dwarf cultivars are the easiest to keep, but even standard varieties can be kept in check with occasional repotting and root pruning.

Q. How long do indoor lemon trees live?

An indoor lemon tree can live for decades. With good care, some lemon trees can survive for 50 years or more.

Q. Where should you place a lemon tree when grown indoors?

Clear sunlight is essential for plant health. Choose a room with large south-facing windows and place the lemon tree as close to them as possible.

Q. Are lemon trees difficult to grow?

Lemon trees are not difficult to grow if your home has a bright location for overwintering.

Q. How can you tell if a lemon tree is overwatered?

A lemon tree that has been consistently overwatered can develop yellow leaves and root rot. Avoid these problems by watering deeply and consistently and by removing standing water from the saucer of the container.

Q. Why do my lemon tree leaves turn yellow?

The leaves of the lemon tree turn yellow in response to overwatering, underwatering, lack of fertility or cold stress. Insect damage can also lead to spotty yellow patterns on the leaves. Follow the best cultivation practices outlined above, and be wary of insect infestations to avoid these problems.

Are you looking for more information on tropical or semi-tropical plants that you can grow indoors? Check out our guides for caring for bird of paradise plants, rubber plants and pineapple plants.

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