Grow Citrus Plants Indoors

Indoor landscaping, also called interior plantscaping, with dwarf citrus plants is a growing trend, not only decorating the home but also freshening the air.

Interior plantscaping with dwarf citrus plants not only decorates the home but also freshens the air

Indoor landscaping, also called interior plantscaping, is a growing trend. Today’s homeowners are using plants not only to decorate their homes but also to freshen the air they breathe. Now dwarf citrus trees, traditionally grown in sunrooms and greenhouses, are finding their way into sunny areas of the home. These trees have glossy foliage and the sweet scent of their waxy white flowers can fill an entire room. Quite often the plants have fruit and blooms at the same time, creating a stunning decorative display. Lemon, mandarin and lime trees, which have a naturally smaller growth habit, are perfect for growing indoors. Other citrus trees, such as oranges and grapefruit, are larger growing and must be grafted onto a dwarf rootstock to control their height for indoor and container growing. These small trees will grow to 1.2 m (4 ft.), but you can keep the height to 1 m (3 ft.) with a yearly spring pruning. You can expect to harvest fruit when a plant is three to four years of age. (Note that the more acidic citrus produce better indoors than sweeter ones.)

Finding a home for indoor citrus plants

Citrus trees are sun lovers, so place them in the brightest area of your home, near a south- or west-facing window, to encourage bloom. In late spring when the nights are warm and frost free, citrus trees can be moved outside to a sunny location. The maximum temperature should be 30° C (86° F) and the minimum 8° C (46° F).

Sheena Adams grows lemons indoors
Sheena Adams illustrates the showy
display of the indoor dwarf citrus tree.
(Photo by Terry Guscott.)

The ideal daily temperature indoors is 20°C (68°F) and it’s best if it remains constant: sudden changes in temperature caused by such things as a drafty window or a heat vent can result in fruit or flower drop. In the evening you can lower the temperature by a couple of degrees: like us they sleep better when it’s a bit cooler.

Potting citrus plants

Container size is important; these plants like to be slightly rootbound. When it’s time to pot them, use a good-quality indoor tropical potting soil. A mature plant will require a planter about 75 cm (30 in.) deep and wide. Be sure the container drains well, as the trees are susceptible to root rot. To increase the air to the root zone, raise your container on pot feet, bricks or a plant trolley.

How to care for indoor citrus plants

When citrus trees are in bloom and fruiting they require extra water. Allow the surface of the root ball to dry out between watering. When the top 7 cm (3 in.) are dry, pour room-temperature water over the root ball until it drains into the saucer; this helps to reduce buildup of excess salts from fertilizers. Be sure to empty the saucer, as the roots should never be waterlogged. A sign of overwatering is leaf discoloration and drop. Citrus trees thrive in high humidity, so thoroughly mist your plants twice a month with tepid clean water. Regular misting produces a healthier plant that is better able to resist insect infestation. While most citrus trees are self-pollinating, some hybrids require a pollinator. To pollinate by hand, gently pass the pollen around using a soft paintbrush or cotton swab. Heavy fertilizing is the key to fragrant blooms, good fruit production and resistance to pests and disease. Twice yearly, in early spring and again in summer, apply a slow-release organic fertilizer; top this up monthly with liquid kelp or fish fertilizer. If you notice yellow leaves, you may need to supplement with iron, magnesium and zinc. All three are common deficiencies of citrus.[pagebreak]

Advantages of indoor citrus plants

A citrus plant is a great addition to the tropical plant collection. It helps clean the air, provides fruit for the kitchen and sweetly scents the home. This holiday season, think of giving someone a citrus plant; it’s a gift that just keeps on giving!

Controlling pests on citrus plants

Frequent pests on citrus are aphids, whitefly and fruit flies. These can be managed safely indoors using an insecticidal soap suitable for attacking soft-bodied insects. If you are averse to spraying indoors, yellow sticky insect cards, available at any garden centre, will attract and trap these pests. The most common pest citrus growers encounter is scale, a sap-sucking insect that is about 3 mm (1⁄8 in.) in length and resembles a small limpet. The adult female is stationary; it attaches itself and secretes a waxy covering, or scale, under which it feeds and eventually produces young. It is generally found on the stems and the undersides of the leaves, but if there is a bad infestation you may notice scale on the topside of the leaf. Under its protective shell, scale can be hard to get rid of. One method is to swab each insect with rubbing alcohol, dabbing just enough to dry out the scale insect but not get much on the leaf itself. If the scale is hard, use a toothbrush dipped in alcohol and gently scrub. This job takes patience and may require a second application, but it really does do the trick. Unlike adult scale, the newly hatched young have legs. During this period they search out a suitable spot to feed, whereupon they settle down to repeat the cycle. At the crawler stage, spray with insecticidal soaps. Monitor your plants twice per month and deal with scale as soon as you spot it. Left untreated, it will damage the plant and stunt its growth. Scale insects also secrete a sticky substance that not only creates a mess but also attracts other pests such as ants.