Oak trees are a common addition to any garden and provide beauty and shade to your landscape. They can grow over 100 feet tall with proper care, and must be nurtured as young trees with fertilizer and a proper planting location. It is best to fertilize the trees when they are young in the spring and fall, as mature healthy oak trees do not need to be fertilized.
Do soil pH test near your oak tree in order to make sure that the soil has a pH between 6.0 and 7.0. Follow the directions on the soil testing kit (found at local gardening stores) to send in the samples.
Regulate the soil as needed. If it is alkaline, add peat moss or sulfur. If it is too acidic, add lime in the fall season.
Use a slow-release fertilizer on a newly planted or young oak tree, so it can get extra nitrogen. Make sure when you spread it around it isn't touching the base of the tree, then water it generously. Apply mulch after to retain the water and fertilizer.
Use fertilizer on young oak trees for their first three years, every fall and spring. After the first three years, begin fertilizing the oak tree in the fall each year with 0.05 pounds of nitrogen per tree for every year of age. Stop increasing the amount once the oak tree turns ten years old. Choose a fertilizer that is high in nitrogen.
Determine how much fertilizer to use according to the directions on the type you choose. On average, you should estimate the number of feet from the base of the trunk to the farthest edge of the root zone, which could be a couple feet outside the longest branches. Then, multiply this distance by itself to arrive at a number of square feet.