How to Grow Carambola

Select a site that receives full sunlight and has good soil drainage. Dig a hole that is approximately three or four times as wide and at least three times deeper than the carambola tree's original container. Replace some of the original soil. Remove the tree from its container and place it upright in the hole. The tree should sit at approximately the same soil level as it does in its container. Refill the remainder of the soil, making sure that the soil surrounds the roots, and water the tree immediately. You might want to stake the tree to help it grow upright. Tie the tree to a bamboo or wooden stake using cotton string.

Add fertilizer approximately every two or three months if your carambola tree grows in a site that has low fertility. Fertilize mature trees once or twice each year if they grow in deep but nutrient-poor soil. Trees that grow in shallow, infertile soil may need three or more applications per year. Depending on the soil type, you may also need to occasionally add iron during the summer months, as well as other micronutrients such as manganese and zinc. You can expect flowers and fruit between one and two years after planting your tree.

Provide your young tree with supplemental water at least once or twice each week for at least the first two years and during the growing season as it begins to bear fruit. You can water your tree less often during the winter. Avoid overwatering the tree, since root rot fungi attack trees that grow in excessively damp soil. Regulate the soil moisture and temperature and minimize weed growth by mulching around the base of the tree, but keep the mulch at least 8 inches away from the tree's trunk.

Prune your carambola tree during the first year or two to help it grow more branches. You can also prune mature trees to encourage them to flower out of season, as well as to maintain their size. To encourage your tree to flower out of season, cut off approximately 12 inches of growth from the long, woody shoots, called whips, and trim off the leaves, but leave about 1/3 inch of the leaf stem on the whip. The whip will begin to flower in about three weeks and will produce fruit in approximately three months.