Caring for a Potted Mexican Lime

Water

• How often you’ll need to water a potted Mexican lime depends on the type of pot, the porosity of the soil and the weather. Unglazed clay pots are porous, so trees grown in them require more frequent watering than those grown in plastic. The Mexican lime requires slightly moist soil at the roots at all times, so use a water meter to ensure it’s getting sufficient moisture. Check the tree more often in hot weather.

Fertilizer

• Mexican lime trees thrive when given lots of nitrogen during the growing season. Fertilize the potted tree in spring, just before it produces new growth. Use a 12-6-6 formula at the rate of 1 teaspoon for every 6 inches of pot size. Reapply the fertilizer every six weeks. Sprinkle the fertilizer granules toward the edge of the pot, keeping it away from the main stem. Water the soil slowly until water just begins to drip from the bottom of the pot after fertilizing. Check the instructions as rates vary by brand.

Pruning

• Take a moment to disinfect your pruning shears by soaking them in a solution of 1 part household bleach in 3 parts of water for five minutes. Rinse the shears in plain water before using them on the Mexican lime tree. Cut off suckers -- new shoots growing from the trunk beneath the graft union -- flush with the tree’s trunk. The graft union is the small "kink" in the trunk near its base. Cut off any branches that cross.

Pest and Disease Control

• Although the Mexican lime isn’t bothered by common garden pests, ants transport scale insects from one tree to another, so control ants to avoid scale. The tree isn’t quite so fortunate when it comes to diseases and is susceptible to a variety of fungal pathogens. A serious disease, lime anthracnose or withertip, starts out with branches and twigs taking on a scorched appearance and brown spots on flowers, fruits and leaves. This disease can be controlled with a solution containing 2 1/2 teaspoons of neutral copper fungicide in 1 gallon of water. Mix the materials in a spray tank and spray the Mexican lime until the product begins to drip from the tree. Humid weather brings out another fungal pathogen that causes scab on the Mexican lime. Scab appears as raised brown lesions over the surface of the fruit. Use a Bordeaux mixture -- available premixed -- and cover the entire tree, including the lower leaf surfaces, with the fungicide.