When Do I Add Fertilizer to Blueberry Bushes?

Before Planting

• Blueberries are fairly specific about their desired soil pH and respond poorly if their demands are not met. If possible, have your soil tested about two years prior to planting to allow time for proper amendment. Blueberries prefer a soil pH between 4.0 and 5.5, with 4.5 being the ideal. Amend your soil with lime if the pH is too low or with sulfur if it is too high. Add organic matter such as peat moss to achieve a level of 4 to 7 percent organic matter in the soil.

Planting

• If soil testing has not been performed prior to planting, amend the soil at the planting site with 1 cubic foot each of peat moss and sand. Plant the bushes in raised beds if you have loamy or clay soil to improve drainage. In sandy soils, the bushes can be planted in level beds. Apply 4 inches of wood chips or sawdust mulch in a 2-foot circle around each plant. Reapply the mulch annually or as needed to maintain a depth of 2 inches.

First Year

• Once your newly planted blueberry bushes have full-sized leaves, you can apply the first fertilization. Use a balanced 10-10-10 or 12-12-12 fertilizer. Spread 1 tbsp. of this fertilizer in a circle a foot away from the bush. Carefully measure rainfall or irrigation, and do not fertilize again until the plant has received at least 4 inches of water and six weeks have passed. Blueberry bushes are very sensitive to over-fertilization, so err on the side of less frequent applications when in doubt.

Second Year

• During the second year of growth, the fertilizer should be doubled to 2 tbsp. and the distance from the plant increased to a circular area 1 1/2 feet from the blueberry bush. Plan the first application for early spring when new growth becomes visible; use the same fertilizer as the previous year. Continue to monitor rainfall to determine the best time for subsequent applications. Pinch off any developing fruit throughout the second season to encourage overall plant growth.

Fruiting Plants

• From the third year onward, you should have an established fruit-bearing plant. In early spring, apply 1 cup of the same fertilizer as previous years. Increase the distance from the plant to 3 feet. Continue fertilization into the summer about every six weeks, provided that the plant continues to receive a minimum of 4 inches of water in this time. Stop fertilization by mid-summer, around July 1. If your soil originally tested with a high pH, apply agricultural sulfur around the bush about every three years.