You are underfeeding your trees. 1 year old citrus tree should be fertilized 6 times per year, a 2 year old tree 5 times a year, a 3 year old tree 4 times a year. A 4 year old tree and older 3 times a year. During the first few years, apply fertilizer to young tree to stimulate vigorous growth of leaves and branches that become the framework of the mature tree. After about 2 to 5 years young trees begin to bear fruit. A commercial citrus tree, for example bears an average of 45, 90 and 135 fruit during years 2,3 and 4 under ideal conditions. The quality of fruit produced on young trees is usually poor compared with that produced by the same tree when mature, so don't get discouraged. The goal of the fertilizer program for young bearing trees is to continue to stimulate vigorous growth of leaves and branches that may compete with early fruit production. After the tree has become established, the goal will be to replace nutrients removed with the fruit and to provide enough nutrients to sustain continued tree growth. Citrus trees are heavy feeders, and require ample nutrition to do well. Fertilizer should not be applied between October 1 and February 1, especially for the first couple years where cold damage can occur. This reduces the possibility of untimely growth flushes in the winter. (U of F)