There are two approaches to fertilization. First, have the soil analyzed by a reputable lab and follow the scientifically based recommendations. The second often referred to as “a general approach,” is to buy a bag of fertilizer and follow the instructions noted. The recommended method is to have the soil tested and analyzed. This informs us which nutrients are required and the specific amounts. This method is the most cost-effective and environmentally friendly way to approach fertilization. Soil test results provide us information on which nutrients are deficient and the quantity to add to help improve the tree’s health and production.
The “general approach” mentioned above is not ideal. Most South Carolina soils have adequate levels of zinc, and overuse of 14-14-14 or 10-10-10 may lead to excessive levels of phosphorus in the soil.
A better approach to fertilization is to split applications rather than applying all of the fertilizer at one time. For example, if a soil test recommends 10 pounds of nitrogen fertilizer, one would typically put out all ten pounds in one application. Instead of applying all 10 pounds at once, split the applications by putting out four pounds at bud swell, three pounds 30 to 45 days later, and apply the remaining 3 pounds 30 days afterward. This approach provides the tree nutrients throughout the growing season while reducing fertilizer losses to leaching and runoff.
Be smart and environmentally conscious this year, and start testing your soil and properly fertilizing! As a result, you can save money, reduce potential environmental concerns, and have a healthier tree.