Bonemeal is a traditional organic source of phosphorus for both fruit trees and ornamentals but it is not the only source. Chemical fertilizers, derived from rock phosphate, can also be used. Bonemeal, however, does have the advantage of becoming slowly available to the roots over an extended period. It is safe to use at planting because it will not burn the sensitive root hairs and can be applied on the soil surface as needed in later years.
Bonemeal is finely ground bones, and varies between 11 percent and 22 percent phosphorus with about 2 percent nitrogen. It is also high in calcium, another element necessary for plant growth. Bonemeal should only be used on soils with a pH of 7 or below, neutral to slightly acidic, to be sure that the phosphorus is in a form that is fully available to the plants. Though more slowly available to roots than chemical fertilizers, phosphorus from bonemeal is available for a longer period of time in the root zone and is often used for feeding bulbs and permanent plantings for this reason.
Phosphorus plays a role in many plant processes and, because it is lacking in many soils, is one of the main elements supplemented with fertilization. Phosphorus is an essential part of photosynthesis, the transformation of sunlight into chemical energy, and the creations of sugars, starches and oils. It helps in proper plant maturation, root growth and blooming. Lack of phosphorus stunts plants and reduces their resistance to stress.
Preparing the Soil For Fruit Trees
Before adding any soil amendments, have a professional soil test done to give you an accurate picture of the nutrients already present. A soil test will tell you the pH of the soil and whether adequate amounts of calcium, magnesium, phosphorus and potassium are present, as well as essential micronutrients. You will also get recommendations on the amount of fertilizer to add. Because phosphorus moves through the soil slowly, the best way to ensure its availability to the roots of your fruit trees is to work bonemeal or other phosphate fertilizer into the soil before planting. Spread a 2- to 3-inch layer of well-rotted manure or other organic matter over the soil, add bonemeal and other materials in the recommended quantity on top of it and mix the amendments into the top 12 inches of soil.
Fertilizing In Later Years
If your young fruit trees are growing 1 to 1 1/2 feet each year, you don't need to add other fertilizers. Bearing trees should make about 1 foot of growth each year. If needed, you can add bonemeal or other fertilizers in a band around the drip line of the tree, the outer edge of the circle created by the branches. Mix into the top of the soil slightly and water well.
- Big Horse Creek Farm: Apple Horticultural Information
- Oregon State University Extension Service: Fertilization: Home Orchards
- University of Minnesota Extension: Understanding Phosphorus Fertilizers
- North Carolina Department of Agriculture: Kid's World: Plant Nutrientes
- Colorado State University Extension: Phosphorus Fertilizers for Organic Farming Systems