Avocados are fruit trees that rarely come true from seeds. In most cases, your avocado tree is bearing stock grafted to a rootstock grown from seed. Avocados produce better if fertilized regularly. The type, frequency, and amount of fertilizer will vary, depending on the age of your tree.
Avocado trees should be fertilized every one to two months, starting from the first productive year. The amount of fertilizer will depend on the age of the tree. Dry fertilizers are generally best applied between March and September, the growing season in places suitable to avocado cultivation, such as Florida and Hawaii.
Fertilizer Amount and Frequency
The timing and amount of fertilizer application varies with tree age. One-year-old trees should be fertilized six times a year with 1/4 to 1/2 lb. of fertilizer per application. Two-year-old trees should have 1/2 lb. to 1 lb. of fertilizer six times per year. Like one- and two-year-old trees, three-year-old trees should be fertilized six times per year. However, they should receive 1 to 1-1/2 lb. of fertilizer. Trees four years and older need to be fertilized four times per year. Add 3/4 to 1 lb. of fertilizer to each fertilization for each year of tree age. Do not give your avocado tree more than 5 lb. of fertilizer, regardless of tree age.
For trees not yet bearing fruit, fertilizers with 6 to 10 percent nitrogen, 6 to 10 percent phosphorous, 6 to 10 percent potash, and 4 to 6 percent magnesium are ideal. Increase the potash 9 to 15 percent for bearing trees and reduce phosphorous 2 to 4 percent.
Apply your fertilizer as indicated by the manufacturer. In most cases, you will spread dry fertilizer around the tree's base and water the fertilizer in so it can reach the roots more quickly. If using organic fertilizers, blend equal parts of the fertilizers and apply on the soil surface. For example, if you are using blood meal and bone meal and your tree requires 2 lb. of fertilizer, use 1 lb. of blood meal and 1 lb. of bone meal.
Organic & Chemical
You can use either commercial chemical fertilizers or organic fertilizers for your avocado trees. Common organic fertilizers for avocado include fish meal, soybean meal, bone meal and composted manure. When using organics, it is important to balance them for proper nutrition. Chemical fertilizers work more quickly, but organics encourage better soil health and reduce the risk of accidental overfertilization.