The dwarf Mexican lime tree is probably best known as a key lime tree. It's also known as West Indian and bartenders lime. The limes are thin-skinned, small and not as cold hardy as other limes, but they are juicy and tasty, making them popular for use in cooking. Mexican lime trees can be grown in containers, and make great patio and house plants. They produce a small white flower before the fruit that will fill the area with a wonderful fragrance. The lime is most famous for its use in making key lime pie.
Water the tree every three days if the tree has been planted within the last three months. After three months, water once a week for a long period of time to soak the roots, if there has not been a good rain. Indoor trees should be completely watered once a week, and more often when dry central heat is on.
Mist indoor trees with a spray bottle full of water during the summer and winter while heat and air conditioners are running. Once a month, take a damp rag and wipe off the leaves.
Apply a slow-release citrus tree fertilizer to the soil around the tree once a month during the spring, summer and early fall. Do not begin fertilizing until the lime tree shows signs of growth.
Harvest fruit as it ripens. Mexican limes have a green to yellow color when ripe, but the best way to tell is to pick one and taste it. Limes will not ripen once they are picked, so they must remain on the tree until they are ripe. Take note of any branches that are having trouble holding the fruit while you're harvesting.
Prune out suckers as soon as you see them. Cut off any dead or damaged branches any time of year. Prune to open up the inside of the tree and to shape the tree after all the fruit has ripened and been removed from the tree. Cut back branches that were too weak to hold the fruit. Pruning will help the tree come back fuller and stronger.
Protect outdoor Mexican lime trees in zone 9 or above from frost. If they are in a container, bring them indoors or place in a greenhouse when temperatures get to about 40 degrees F at night. Ground-planted trees should be covered with a blanket or tarp when a frost is expected. Build frames around the tree with PVC or wood to hold a piece of plastic sheeting or blanket in place without damaging the trees.