The best fertilizer for pear trees is a balanced 10-10-10 formula of nutrients. This fertilizer blend is made of equal amounts of nitrogen, phosphate and potassium.
Soil testing is the best way to determine the exact nutrient mix of the soil a pear tree is planted in. Unless soil analysis determines otherwise, a 10-10-10 formula provides everything the tree needs. Fertilizing a pear tree with compost, well-composted manure or bone meal also improves the soil and benefits the tree. Fertilizer should be applied after thorough watering in the spring and fall. Compost can be applied at any time during the growing season until the time of harvest.