Fruit trees typically have different nutritional needs than other types of trees, so most of the time, fruit tree fertilizer will have a completely different chemical makeup than other tree fertilizers. In addition, different types of fruit trees may require a specific type of fruit tree fertilizer, so it is a good idea to become familiar with the needs of your specific tree before making a choice in fertilizer. You can use either all organic fertilizers or chemical compounds, as long as the fertilizer has the necessary nutrients required by the tree.
Before you purchase any type of fertilizer, you need to measure the nutrients in your soil against the nutrient requirements of the tree. Soil testing kits can be purchased at most hardware stores and plant nurseries. Once you have an idea of your soil content, you can choose a fertilizer that can help you achieve a soil balance that is right for your tree.
Citrus trees, such as lemon or orange, need a type of fruit tree fertilizer different from what may be required for growing apples or pears. Citrus trees are considered “hungry” trees and may need to be fertilized every month. Citrus trees need fruit tree fertilizer that has trace amounts of magnesium, copper, and zinc. In addition, these trees require highly acidic soil, so if your soil has low levels of acid, you might want to be sure that the fertilizer you choose is acid-based. Most nurseries sell fertilizer especially designed for citrus trees.
Apple and pear trees usually require fertilizer that is high in nitrogen. In many cases, depending on soil content, nitrogen may be the only additional nutrient the tree will need. Ammonium sulfate or ammonium nitrates are usually considered good nitrogen-based fertilizers for these trees. If the soil has a high content of alkaline, it may be necessary to add a good all-round fertilizer to help complement the nitrogen additives.
Peach and plum trees usually require a type of fruit tree fertilizer that contains phosphorus, potassium, and nitrogen. This type of fertilizer is often referred to as “complete” fertilizer. These tree should be fertilized during their first spring growth and then once per year thereafter.
You may decide that you want to use only organic fertilizers such as manure or compost. If so, it is probably a good idea to check with your local agriculture extension office to help you determine which type would work best for your specific tree and the soil it will inhabit. Extension offices typically have agriculture specialists who can give you expert advice on how to use all types of fertilizers.