Do Citrus Trees Need Fertilizer?
Citrus trees grow best when provided with appropriate amounts of fertilizer. These trees offer not just a wealth of dark-green leaves that stay on the trees all year long, but also flowers and edible fruit. They are known to be heavy feeders, so you will do well to learn how and when to provide citrus tree fertilizer. Citrus trees of all species have a tendency to bear a heavy load of fruit one year, then a lighter load the next year. They continue to alternate. However, appropriate fertilization reduces alternate bearing. It also will help preserve a citrus tree's resistance to fungal diseases.

Best Fertilizer for Citrus Trees
In an ideal world, the soil in which citrus trees are growing will offer them all of the nutrients they need. But most of us live in the real world, where nutrients leach out of soil as it is irrigated. The best fertilizer for citrus trees is one that supplies exactly what the soil lacks.
That means that it is difficult to provide general advice on how to fertilize citrus trees since soil conditions are not universal. The place to start is with a soil analysis. This will let you know what nutrients your soil already offers, and which nutrients need to be added with citrus fertilizer.
Citrus trees require phosphorus to help new roots develop at planting as well as to promote blossoms, nitrogen for growth, and potassium for healthy fruit development. Micronutrients like zinc and iron are also necessary. Once you know what your soil already contains, you can locate a fertilizer that complements the soil and completes the citrus fertilizer package. If you don’t opt for a soil test, use a complete fertilizer with micronutrients.

When to Fertilize Citrus Trees
If you are wondering exactly when to fertilize citrus trees, you will find that experts agree that three different feedings are beneficial throughout the growing season. The timing depends in part on the species of fruit and the age of the tree.Generally, citrus should be fertilized three times a year. The total annual dosage is split into thirds with one portion provided at early bud break in January or February, a second a few months later at fruit swell. The final third should be given to the tree in May or June for oranges, tangerines, and grapefruit, but for lemons and limes, the final fertilizer is given in August or September instead.

How to Fertilize Citrus Trees
For a new citrus planting, spread the dose of fertilizer around the soil about 30 inches out from the tree. For established citrus trees, spread it on the soil twice the diameter of the canopy. In all cases, keep fertilizer away from the trunk. What about micronutrients? If your citrus lacks micronutrients such as zinc or iron, supply these with a foliar application of a liquid-chelated micronutrient solution as the new growth emerges in the spring.