What Kinds of Fertilizer Do You Put on Blueberry Plants?

Preparation

• Before applying any type of fertilizer, use a soil test to determine the pH of the soil where you want to plant your blueberries. Also test for the levels of potassium and phosphorous in the soil. Understanding what the soil has and what it lacks helps you figure out what to use when fertilizing your blueberries. Blueberries do best in soil with a pH between 4 and 4.5. Lower the pH with sulfur or aluminum sulfate, or raise it dolomitic lime, as necessary.

Organic Matter

• According to the University of Rhode Island, blueberries need soil that is fertilized with between 4 and 7 percent organic matter. Include organic matter by sowing green manure crops like buckwheat, hairy vetch or white sweet clover on the site. Plow these crops directly into the soil before planting blueberries. Alternately, mix 1 to 1½ gallons of sphagnum moss into the planting hole for the blueberry canes.

Fertilizer Types

• When choosing a fertilizer for a blueberry plant, look for one that has a 16-8-8 concentration of nitrogen, phosphorus and potassium. Look for fertilizers in this concentration with an additional 4 percent of magnesium. These fertilizers are tailored specifically to meet the blueberry's needs and encourage lush growth and heavy fruiting.

Applying Fertilizers

• When dealing with young blueberry plants, apply fertilizers carefully by hand to each individual plant. When the plants get older, use a broadcast applicator. Apply fertilizer to blueberry bushes only when the foliage is dry. One way to apply fertilizer effectively is to do it in the early spring, before there are leaves present.