Did you know? The name actually derives from its association with the Florida Keys, where it is best known as the flavoring ingredient in Key lime pie.
Common name : Key lime
Scientific name : Citrus aurantiifolia
Family : Rutaceae
Category : Fruit plants
Type of plant : Perennial
The key lime is a pretty shrub 3 to 5 meters high, producing limes that are valued for their unique flavor compared with other limes.
Because of its more tropical origins, it is the most sensitive member of the family, and can suffer from frost under -2 ° C.
In tropical and subtropical climate it is covered all year round with small white and red flowers, but in warm Mediterranean climate flowering occurs only in spring and autumn.
An important note : the key lime is self-fertile, which means that only one plant is needed to ensure fruiting.
Sowing & planting
200 - 500
6.3 - 6.8
Identify my key lime
C. aurantiifolia is a shrubby tree growing up to 5 m (16 ft) with many thorns. The leaves are ovate, 2.5–9 cm (1–3 1⁄2 in) long, resembling orange leaves - the scientific name aurantiifolia refers to this resemblance to the leaves of the orange tree, Citrus aurantium. The flowers are 2.5 cm (1 in) in diameter, yellowish white with a light purple tinge on the margins.
Plant my key lime
Plant your key lime tree in a pot, except in a really mild climate.
Choose a large container, preferably made of terracotta with a hole at the bottom to ensure water drainage. Place a thick layer (about 20% of the pot's volume) of gravel or clay pebbles at the bottom of the pot. Make a mixture of good manure, potting soil, compost, and medium grained river sand. Spread a layer of this mixture at the bottom of the post and place your key lime so that the end of the stem slightly exceeds the pot's top as it should never be buried. Fill the empty space with the mixture and tamp it around the plant. Water generously to eliminate any possible air bubbles in the soil. Add more mixture on top if necessary.
In open soil, plant the key lime in direct sunlight, sheltered from wind, ideally next to a wall, in light slightly acidic well drained soil.
However, never try to cultivate the plant inside an apartment. It cannot handle the heat.
Water my key lime
Did you know this? The key lime has a way to tell you that it's thirsty.
Leaves pointed upward signify that it doesn't have enough water. On the other hand, leaves pointed downward means that there's an excess of water!
That said, during good weather, an outside potted key lime is subject to a high level of evaporation: it therefore must be watered very regularly during this season for optimal growth. The mixture should never completely dry between two watering in summer, but water should never stagnate in the container.
In winter, water even more steadily as long as the tree is bearing fruit — after, you can reduce to just once a month, leaving the substrate slightly dry between two waterings.
Repot my key lime
A potted key lime needs regular provisions to stay in shape!
Repot in spring about every 2 to 3 years by changing the substrate as much as possible to a potting soil specially for citrus fruit or planting. Ensure that the bottom of the pot has a hole - add some gravel to the bottom for drainage.
Shelter my key lime
Starting in autumn, bring in the pots.
Have your potted key lime spend winter in a bright frost-free spot: the ideal temperature is between 8 and 12°C - definitely not in your living room or else resign yourself to living in these temperatures.
During winter, keep watering your tree as long as it is still bearing fruit, then you can space out the watering, letting the substrate dry slightly between them.
Put outside my key lime
Take your potted key lime back outside starting in May. Find it a nice spot in direct sunlight but sheltered from wind, which dries out its leaves.
Protect my key lime
If your key lime is planted in open soil, but you fear a possible frost, don't hesitate to cover its base with a good layer of dead leaves for the harshest weeks.
Also wrap the stem in a thick mat (woven bulrush, cane, rye or rice straw...), held by ties. You can also cover the foliage with a wintering cover.
Fertilize my key lime
The lime's love of water accelerates soil leaching: therefore, it really must be fertilized — especially for potted trees!
For a plentiful harvest, regularly provide a fertilizer rich in nitrogen and lye — you can find fertilizers appropriate for citrus fruit in stores or try with a compost. In winter, reduce the provisions to once a month. In spring, start back up with a frequency of once every two weeks.
Prune my key lime
Trim your lime tree to encourage more offshoots for a more compact and less spread out habit.
For the first years, cut each new stem once the growth is finished — the new leaves will be darker and tougher — leaving it at a length of 20 cm.
The lime is pruned once a month from May to September until the tree has taken its shape. Thereafter, only one pruning per year is necessary at the end of winter. Remove dead or diseased branches as well as those that overlap to open up the plant and let light in.
Check on my key lime
Watch over your key lime tree in winter: if the leaves darken, it's a cold spell, and if they lighten, it's a lack of fertilizer!
The key lime can also have other troubles:
Aphids are seen with the naked eye under the leaves near the veins. Spray the leaves with soapy water or a mixture of water and olive oil which will additionally nourish your plant.
Scale insects enclose themselves in a brown shell or under a white coating on the back of the leaf against the main vein and excretes honeydew which will attract fungi.
Is the lime foliage faded? Its green is becoming a silver gray? Small spider webs are forming at the ends of the leaves? Your lime has been attacked by red spiders.
Between the scale insects and red spiders, you can moisten the foliage as a precaution several times a week with soften and unbleached water.
Mulch my key lime
Native to tropical regions, limes love well drained cool soil. Their roots are mostly superficial, and they don't like the presence of weeds or other plants that compete with them. Mulch to avoid having to weed and to keep the roots cool! Pine needles are perfect for this.
Reap my key lime
The harvest takes place from November to March. Thus, the fruits often ripen inside. Keep the ground slightly damp until you pick the last fruit.