Citrus can be grown outdoors (and are cold-hardy) in zones 9 and 10. They also grow well as houseplants if properly cared for.
These tropical plants like bright sunlight and high humidity. Give your citrus a sunny spot indoors, preferably a south- or southwest-facing window. If natural light is insufficient, provide supplemental lights.
Citrus trees need a minimum of six to eight hours of sunlight daily, and they thrive in warm temperatures. Find a sunny spot for your tree and keep it away from drafts, air conditioners and vents that can affect the temperature or moisture levels in the soil.
If the leaves of a citrus plant begin to wilt, this could be a sign that it is getting too much sun. If this happens, move the citrus plant to a more shaded area and apply a fungicide to prevent leaf burn.
Citrus plants grow well in the ground outside in mild climates and also do fine in containers or planter boxes, where they can be moved indoors before a freeze threatens them. When planting outdoors, amend poor soils and space the plants properly, taking into account their eventual mature size. In colder climates, use a protective mulch but not one that encases the citrus plant. Some citrus varieties like satsuma and mandarins are particularly sensitive to freezing temperatures.
Citrus plants are very thirsty and need to be watered regularly especially during the growing period. Plants in pots and planters should be fed with a high potassium feed to boost fruit set, we recommend the Westland Citrus Feed which is available at our garden centre.
If citrus plants are grown as houseplants they should be moved outdoors once the risk of frost has passed and given a warm, sheltered spot that is protected from wind. If they are kept in pots or planters they should be repotted every three years to keep the root ball healthy.
When planting a citrus tree in the ground, it is best to plant in early spring to reduce the risk of damage by winter cold and frost. Dig a hole that is as wide and deep as the root ball. When planting, combine SummerWinds Organic Planting Mix with the existing ground soil. Water heavily after planting and regularly for the first few weeks of growth, then reduce to occasional heavy watering during the warmer summer months.
Citrus trees are heavy feeders that require fertilizer that includes nitrogen, calcium and potassium. They also need trace micronutrients and can benefit from the addition of soil amendments, particularly in clay soils that bind to iron.
These trees can be planted year-round in warm climates but spring planting minimizes shock and stress. A hole that is twice as large as the container the citrus comes in should be dug to avoid root rot and encourage strong roots.
Incorporate a weed-free, organic soil amendment such as compost or manure and mulch around the base of the tree to conserve moisture and help suppress weeds. If you plant your citrus in the ground, begin fertilizing it with a liquid or granular blend formulated specifically for citrus every 6-8 weeks during the growing season until it goes dormant in fall. If you grow your citrus in containers, prune suckers and regularly apply a granular citrus fertilizer such as Scotts Osmocote control-release fertilizer and spread it around the drip zone (the area within 2 to 3 feet of the exterior foliage). Citrus trees that are moved indoors for the winter should be slowly acclimated by gradually reducing light exposure or partial shading for 2-4 weeks before moving them to full sunlight.
Citrus trees need some pruning to keep them looking good, promote fruit production and prevent disease. The right kind of pruning also encourages new growth that can help with tree health and harvest.
Young citrus plants benefit from light pruning to remove suckers that grow from the base and interfere with tree development, as well as removing damaged limbs. Mature citrus do not require extensive pruning for production, though a few selective cuts can be helpful to shape the tree and control height. It is also important to prune away the vertical shoots called “water sprouts” as they take a lot of water and nutrients from the plant and rarely produce fruit.
Citrus are typically pruned in late winter or early spring, after the weather has warmed but before blooms appear. Pruned citrus trees tend to focus more on regrowth and recovery than the upcoming harvest. It is not recommended to prune citrus in fall or winter because the exposed bark can be susceptible to sunscald.