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How to Grow a Key Lime Tree and Care for Them?

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Key lime, also called Mexican key lime and the West Indian lime, is a citrus hybrid. The fruits have a moderate size but have thinner peels and strong flavors. Being a tropical plant, it fruits heavily in early summer and late fall, but steadily throughout the year.

Key lime fruits are known for their intense aroma and distinctive flavor. They are widely used for cooking pies, tarts, and beverages. Pairing key limes up with the right ingredients, you can create some exceptional delicacies. 

Lime Tree

But, what’s better than organic key limes straight from your garden? If you’ve been wanting to plant key limes in your garden, this article will shed light on the entire process from propagation to harvesting. Look out for some helpful tips and suggestions to remember as well.

Read on to find out more!

Key Lime Tree

Botanically called Citrus aurantifolia Swingle, Key lime is considered to be a hybrid of three plant species – Citron, Pummelo, and Citrus micrantha. It is also known as the West Indian lime, Mexican lime, Dayap, Manao, Chanh, etc. 

The key lime tree is small and bushy with slender branches. It usually has heights lower than 12 feet or 4.1 meters and thorns that are short to medium in length. The foliage is dense and leaves are small, pointed, and pale green.

Key Lime Tree
Source: britannica.com

Spineless species grow more in a compact and upright form with a dark green foliage. The fruit production, however, is comparatively lower.

Suitable Geographical Conditions for Key Lime Tree

Originally, the key lime was brought into European countries like Spain and Portugal by the Arabs. The Spanish and Portuguese further carried the plant to America in the early 16th century. In America, this plant was initially cultivated in the Florida Keys and parts of Central and Southern America.

The plant owes its name to Florida Keys but is grown sparsely in Florida today. Instead, key limes grow best in warm tropical and subtropical regions. In the USA, these plants are grown in the plantation zones 9 to 11. 

Major producers of this fruit are Mexico, India, Egypt, and the West Indies. 

Some other suitable geographical conditions include:

  • Temperatures: The plant is highly sensitive to cold temperatures. The foliage gets severely damaged at temperatures lower than 32 degrees Fahrenheit (0 degrees Celsius). Hence, warm temperatures are mandatory.
  • Season: Even though the plant fruits year-round, the prime season is summer. Fruits produced have the best quality in the warmest locations.
  • Soil: Key lime trees can be grown in a variety of soils. However, deep sandy soils promote vigorous growth. These plants also require soils with good drainage capacities.
  • Sunlight: Key limes should be planted where they get ample sunlight. Ideally, they need 10 hours of full sunlight. Additionally, they flourish in areas with good air circulation.
  • Rainfall: These plants require low to moderate rainfall and don’t tolerate flooded conditions.

Looking for other indoor plants too? Check out the different types of succulents here!

When to Plant Key Lime Tree?

The right time to plant key limes depends on where you will be planting the trees. Potted plants can be grown any time, provided they are watered appropriately and get enough sunlight.

On the contrary, if the plants will be grown in soil, then it is suggested to plant them in early spring or late winter. This will allow enough time for the plant to settle before its flowering and fruiting seasons.

Flowering and Fruiting Season 

The key lime flowers grow in clusters along the stems. They are small and fragrant with white petals. Flowering occurs mainly in spring but can be observed throughout the year. 

Fruiting mainly occurs in summers. Depending on the propagation method, the fruiting may occur at varying times. 

Flowering and Fruiting Season

For instance, key lime trees grown from cuttings or air-layers, fruit within a year of planting. Seedlings require up to 2 years before producing fruits. Those cultivated from budding or grafting will fruit within 3 years.

Propagation of Key Lime Tree

In tropical areas, they can be planted outdoors. Preferably, they should be planted in a sunny location in a trench. 

However, for people living in colder areas, the plant will have to be grown in a container. For this purpose, choose dwarf varieties of the plant. These will grow to a manageable size and have a shallower root system.

Note that key lime plants grown indoors need to be pollinated by hand.

Here’s how you can propagate key lime trees:

1. Propagation by Seeds

Key lime has polyembryonic seeds which means that they have multiple maternal layers to them. Multiple trees can be produced from one seed and these trees will be identical to each other and the parent tree. 

Key lime seeds don’t need to be prepared or treated before sowing. They can be planted at any time of the year. This is a reliable method but it may take up to 5 years for the tree grown to start fruiting.

2. Propagating by Air Layering

This method involves selecting a suitable stem from a pre-existing plant and treating it to prompt root development. This stem is then cut from the tree and planted. Remember, air layering is best carried out in the summer season.

Propagating key lime trees by air layering results in trees that are identical to each other and to the parent tree. The process may take a long time but the trees fruit as early as the very next fruiting season.

3. Propagation by Cutting 

Stem-tip cuttings are another favorable method of propagating key lime trees. It includes the following steps:

  1. Choose the appropriate tree and branch: The tree should be healthy with a decent history of flowering and fruiting. The branch chosen should not be bearing any flowers or fruits. 
  2. Cutting: Cut across the branch at about 3 inches from the end of the branch or the leaf node. 
  3. Stripping: Strip off any leaves on the lower two-third part of the branch.
  4. Rooting hormone: Dip the branch end in a suitable rooting hormone.
  5. Peat moss: Fill a pot with peat moss and water. When the mixture has a sponge-like consistency, insert the stem halfway in the center.
  6. Cover: Cover the pot with a plastic bag and place it in a sunny location.

To encourage root growth, water moderately. And once the roots sprout, you can carry out a transplant.

Been wanting to plant flowers? Learn how to grow roses from cuttings with this detailed guide!

Plantation of Key Lime Tree

The plantation of key lime trees varies with the type and fertility levels of soil. Generally, they should be planted around 12 to 20 feet away from other trees. Overcrowding will result in competition, and eventually, abnormal growth. 

Also, key lime trees can potentially get damaged by the use of lawnmowers and weed whackers. Hence, they should be planted at least 2 to 5 feet away from grassy areas. 

Key Lime Tree
Image: fast-growing-trees.com

For areas prone to flooding, key lime trees should be planted on a mound. The major steps include:

  1. Build a mound that is 2 to 4 feet high and 4 to 10 feet in diameter. 
  2. Dig a hole 3 to 4 times the diameter and 3 times as deep as the container the tree came in.
  3. Backfill the hole with some native soil.
  4. Plant the tree, ensuring adequate space for root growth.
  5. Fill in the hole and tamp lightly to eliminate air spaces.
  6. Water immediately.
  7. Stake the tree with a wooden stick or bamboo, if required.

Remember that the above steps are general and common to all soil types. There might be additional preparations needed for different soil types.

Watering Key Lime Tree

A newly planted key lime tree should be watered on alternate days in the first week. Then, watering can be reduced to 1 to 2 times a week for the first two months. Afterwards, they can be watered when the soil dries out.

Watering Key Lime Tree
Image: youhadmeatgardening.com

They need to be watered periodically during prolonged dry periods. In the rainy season, irrigation can be further decreased. 

Mature key lime trees do not need regular watering. Frequent watering may lead to damage and the plant growth may decline. Too much watering may cause root rotting as well. 

Fertilizer for Key Lime Tree

Key lime trees only need to be moderately fertilized to prevent diseases and boost growth. Typically, the fertilizer compositions have to be 6-6-6-2 as in 6% nitrogen, 6% phosphorus, 6% potash, and 2% magnesium. 

Remember, around 20 to 30% of the nitrogen content should be from organic sources.

For a new plant, ¼ lbs of a young tree fertilizer can be used every 3 to 4 months in the first year. As the plant matures, this amount can be gradually increased. Mature trees should be fertilized 3 to 4 times a year by applying 1.5 to 2.0 lbs of fertilizer. 

Also, if the plant develops certain nutrient deficiencies, then it will have to be fertilized correspondingly. For example, a plant showing iron deficiency symptoms (yellowing leaves and darker interveinal areas) should be supplemented with iron chelate. 

Note that the pH level of the soil should also be accounted for.

Also read: 2021 Best Fertilizers for Yards and Gardens

Mulching 

Mulching helps in retaining adequate soil moisture, improves soil quality, and reduces weeds. A 2 to 6 inch layer of mulch including wood chips, bark, etc. is considered ideal. 

However, the mulch should be placed 8 to 12 inches away from the trunk. This is because mulch near the trunk may lead to trunk rot.

Pruning

Key lime trees don’t require regular pruning. Prune them only to shape them, to get rid of dead branches, or to limit the height. It is better to limit their height to around 6 to 8 feet because taller trees fall over and are difficult to care for.

Harvesting & Storage 

While harvesting, make sure to pluck only the ripe fruits because the trees may simultaneously fruit at different stages of development.

The fruit can be stored in polyethylene bags in the refrigerator for several days. Sealing them properly in plastic bags will help to preserve them for long. Key lime juice can be frozen and stored for around 4 months.

Pests/Diseases

Some pests that attack the key lime tree are:

  • Brown Citrus Aphids: These pests are shiny black in their adult forms and dark red or brown as nymphs. They feed on new growth, cause distortion, and further stem dieback. 
Brown Citrus Aphids
Image: pestnet.org
  • Citrus Leaf Miner: These insects have black and tan markings with white wings. Their mining causes distortion in leaves, rendering them dysfunctional. They often attack new and younger plants. 
  • Citrus Red Mites: Red mites have round bodies that are deep red to purple in color. They attack the upper leaf surfaces and suck the leaf sap, causing brown spots. 
  • Snow Scale: Male scales are white and may cluster along the tree trunk. The females have colors ranging from brown to purple. These scales cause bark splitting which weakens the tree and sometimes, kills the limbs.

Did you know that spider mites are mites that are almost invisible to the naked eye, but can cause severe damage? Learn how to get rid of spider mites with this guide!

There are some diseases that limit key lime plants’ potential to grow in the home landscape. These mainly include the following:

  • Citrus Canker

Key lime trees are extremely vulnerable to this disease. It is a bacterial disease that can be spread by wind, contaminated equipment, animals, or humans. 

The first symptoms include pinpoint spots. These are followed by more noticeable raised, brown spots. When infested heavily, this disease leads to defoliation and weakening of the tree. 

  • Citrus greening

Also called the yellow shoot disease, this one is spread by Asian citrus psyllid insects. Its symptoms are observed as yellow blotches, yellow veins on leaves, and reduced leaf size. 

The disease infects the tree’s phlegm tissues, causing a decline in growth and fruit production.

Uses & Health Benefits 

Key lime fruit has several benefits and can be used for a wide range of purposes. Some of these include:

  • Key lime juice has zero cholesterol value and a high nutritional content. It is also rich in vitamins A and C.
  • In cooking, its juice is used to enhance flavor. Key lime fruits are used extensively in pies, beverages, and other savory dishes.
  • One of the by-products includes lime oil, which is used as a flavoring agent as well.

Frequently Asked Questions

What’s the difference between regular lime and key lime trees?

The key lime fruit is much more aromatic, and contains more juice in comparison to the regular lime. Also, the key limes are yellowish and have more seeds. 

Do you need to plant 2 trees to produce fruit?

When a key lime tree is planted outside, its pollination is carried out by bees and other pollinating insects. Therefore, there is no need for 2 trees for fruiting. However, container-grown plants have to be pollinated by hand.

How much sun does a Key lime tree need?

Key lime trees thrive in a location with ample sunlight. Ideally, they need 10 hours of full sunlight, but can do well in 6 to 8 hours of sunlight as well. Remember to protect them from the northern winds.

Growing Key Lime Tree: Conclusion

To conclude, key lime is a lovely evergreen plant to add to your collection. Its savory fruit and white delicate flowers are another plus. On top of everything, this plant is exceptionally low maintenance. 

Growing a key lime tree on one’s own isn’t particularly challenging. With the right information, even amateur gardeners can plant and care for key lime trees. 

We hope that this article provided you with everything you need to get started with. We also hope you cherish these plants and have fun taking care of them.

Bonus Read: 7 best soil test kits for your garden

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