The Key Lime tree is native to Southeast Asia. The plant is also called the Mexican Lime tree. There are two common varieties that are grown indoors, the standard-sized plant and the dwarf variety. Key Lime plants adapt well to growing indoors as they are sensitive to cold temperatures.
Key Lime Tree Appearance
The Key Lime plant grows to a height of between 6 to 12 feet (1.8 to 3.6 meters). Key Limes are smaller than the common Persian Lime with a flavor that is more tart. The leaves are glossy and oval, growing on spiny stems. Blooms appear in spring as white, star-shaped flowers. Once the flowers die off, the fruit begins to develop. A mature lime grows to approximately 2 inches (5 cm) in diameter.
Key Lime Plant Sunlight Requirements
Provide between 6 to 8 hours of direct sunlight per day. Low lighting inhibits fruit production, so supplement with an LED grow light if needed. Move the plant outdoors during the summer if possible as the tree will benefit from the warmth and sunlight.
Watering Your Mexican Lime Tree
Keep the soil moist but not soggy. When the top 2 inches of soil feels dry, water the plant thoroughly. Pour until the water runs through the pot’s drainage holes, then dispose of the water collected in the saucer.
Soil and Fertilizer Requirements
Grow your Key Lime tree in a well-draining, loamy soil. Fertilize the tree once every two weeks, starting in spring and continuing until fall. Use an organic fertilizer designed for citrus trees. The nutrients from the fertilizer promotes healthy roots, more flower production, then a larger fruit yield.
Temperature and Humidity Levels
Maintain temperatures between 65 and 75 Fahrenheit (18.3 to 23.8 Celsius) for optimal growth. Avoid temperatures below 50 F (10C) as it will damage the plant. Humidity levels should be at 40 percent or higher. Supplement low humidity with a humidifier or a pebble tray.
Harvesting Your Key Limes
The Key Limes are typically ready for picking five to six months after the tree blooms. While the limes are technically considered ripe once they turn yellow, fruit at this stage is bitter. Instead, pick the limes when they are a bright green. To ensure the limes are at peak flavor, pick one and cut it open. The inner fruit should be juicy and the outer skin should be smooth.
Propagating Key Lime Trees
Key Lime plants are propagated best with cuttings. Snip a stem, in the early summer, that is around 4 inches long. Coat the cut end in a rooting hormone. Plant the stem in a pot filled with a loamy soil mix. Moisten the soil, then cover the stem loosely with plastic to retain moisture. In 6 to 8 weeks the stem will grow its own roots.
Common Pests and Diseases
Aphids, scale, and mites are common insects to watch for on your Key Lime tree. The pests will feed on your plant, causing damage to leaves and branches. For a chemical-free way to control the infestation, wipe the insects off with a cotton swab dipped in rubbing alcohol. Follow up with spraying the tree with water to remove any insects you missed and residual honeydew.
Root rot is caused by either overwatering your plant or using soil with poor drainage. Remove any affected foliage and repot in a lighter soil if necessary. For advanced cases of rot, inspect the root system and trim away any dark and mushy roots. Repot the plant in a clean pot with fresh soil to eliminate the soil bacteria causing the rot.
Having your own mini citrus plant indoors is easier than you might think. The Key Lime tree is adaptable to most home environments and will provide you with tart and tasty limes for years to come.
Key Lime Tree FAQ
Yes, limes are considered toxic to pets and should be kept out of reach.
The tree will grow outdoors in USDA zones 9 to 11.
The limes are high in both antioxidants and vitamin C and aid in wound healing.
Repot your Key Lime tree in the spring. A general guideline is to upgrade the size of the pot once the tree is two and a half times as tall as the pot is.
Use key limes to make the well-known pie, as well as a complement to other fruits and many vegetables.