Citrus trees want to bloom. After all, blooming is the first step in tree reproduction. There are many different reasons a fruit tree won't bloom: age, nutrition, water needs and disease are just a few of them. Once you have identified the problems preventing your tree from blooming, and corrected those problems, your tree should put on a dazzling floral display for you each spring.
Check the age of your tree and check with your local nursery to see if your tree is of the minimum age to bloom and set on fruit. Make sure the tree is showing no signs of disease, such as soft spots in the wood, powder on the branches or other signs.
Test your soil. Take samples from three areas under your tree and mix the samples together in a clean, plastic jar. Seal the jar and take it to your local agricultural extension office or your local nursery (for directions on where to take it) and have the soil tested. Make sure you tell the lab the type of tree from which the soil was taken.
Add the amendments to the soil that the testing lab recommends, in the proportions that the lab suggests. Include citrus tree fertilizer, as per the manufacturer's recommendations. Water the amendments and fertilizer into the soil and keep the soil under your tree damp but not soggy. Citrus trees need a lot of water just prior to blooming and throughout the fruit-setting period.
Prune your citrus tree in early spring, before new growth begins. Start by removing all dead and diseased branches. Next, remove any branches that are growing sideways across the canopy of the tree and any branches that are rubbing against each other. Cut any branches growing down or straight up, especially those trying to compete with the main trunk. Remove all suckers from the roots and trunk—suckers have a smooth skin rather than true bark.