When fertilizing peach trees in a backyard setting, consider tree age and growth rate, soil/tissue analysis, as well as location. Since peach trees do not produce fruit during the first two years after planting, less fertilizer is required than is needed for mature fruit-bearing trees. Visual indicators, such as leaf discoloration and weak growth, are symptoms of nutrient deficiency. Perform a soil test before planting to identify soil factors, such as pH that may cause certain nutrient deficiencies. For more information, see HGIC 1652, Soil Testing. Once trees become productive, test their nutritional status with a leaf analysis. In July, take a leaf sample consisting of 50 to 100 fully expanded leaves (at the 4th-5th node.) Take the sample from non-bearing shoots located at about 5 feet height throughout the tree canopy. If there are several similar trees in the same area, take a composite sample.
HGIC 1000, Fertilizing Trees and Shrubs, provides general guidelines for tree fertilization, including using natural fertilizers. Mature peach trees mostly require nitrogen (N) and potassium (K), the two nutrients found at higher concentrations in fruits. Phosphorus encourages root development and is essential for young trees. Use a complete fertilizer, such as 16-4-8, 12-6-6, 12-4-8, or 10-10-10, during the tree’s first three years. Fertilize mature trees with the previously listed fertilizers or other N and K fertilizers such as potassium nitrate. Calcium, magnesium, and most plant micronutrients are used in relatively small amounts. Therefore, these nutrients are generally not required to be added unless a soil/leaf analysis reveals low or deficient levels.
Split fertilization applications by making the first application starting between bloom and petal fall in March, two months later in May, and at postharvest if any fruit is harvested. Do not apply fertilizer later than August 15th. Apply fertilizer around the tree’s root zone area, see HGIC 1000, Fertilizing Trees and Shrubs for more information. For more information on general peach tree care, see HGIC 1354 Peaches and Nectarines.