Oak trees are an ideal addition to any landscape, providing shade, beauty and seasonal fall colors. Although they grow slowly, they can get over 100 feet tall if cared for properly. The key to caring for oak trees and helping them get to maximum growth is to nurture them as young trees with fertilizer. Spring and fall are the best seasons to fertilize a young oak tree. Keep in mind that very mature oak trees (20-plus years) do not need to be fertilized.
Text the soil pH near the oak tree. For ideal growth, the soil around the tree should be between 6.0 and 7.0. Follow the directions on the testing kit to send in the samples.
Maintain and change the soil as necessary. For acidic soils, add lime in the fall. For alkaline soils, add some sulfur and peat moss.
Apply a slow-release fertilizer on a young oak tree for extra nitrogen. Use gloves when layering it, and make sure it doesn't touch the base of the oak tree. Water generously after applying the fertilizer to get it integrated into the soil. Layer mulch around two inches thick in order to retain the water and fertilizer.
Fertilize young oak trees for their first three years, every fall and spring. During the fourth year, begin fertilizing only in the fall. Use 0.05 pound of the fertilizer per every year the tree ages. After 10 years, stop increasing the amount of fertilizer. Switch to a fertilizer that is high in nitrogen at this time.
Figure out how much fertilizer you need to use. This depends on the type of fertilizer and directions. On average, you need to multiply the number of feet from the tree's base to the farthest edge of the root zone by itself to get the number of square feet. The end of the root zone could be several feet further out than the longest branches.