Extension

Gardening enthusiasts with a penchant for growing fruits need to remember that regular maintenance of fruit-producing trees, shrubs and vines will maximize quality and yield. It is best to start with healthy soil, then maintain it with regular fertilizing.

Several fruit crops require fertilization at the start of the growing season. Different fruit crops have various nutritional requirements, so it’s important not to treat all crops the same. And remember, nutrient requirements change as plants age. Fertility management is important to maintaining the health of perennial fruit crops during their lifespan.

Fertilizers supply nitrogen in two forms: ammonium or nitrate. A slow-release nitrogen source is most desirable to prevent excessive nitrogen losses through leaching during irrigation. Oklahoma State University Extension offers research-based fact sheets that provide gardeners with detailed information about various fruit crops.

Gardeners who are growing blueberries can get detailed fertilizer information in HLA-6248 Blueberry Production for the Home Garden. Apply nitrogen in small applications – once before bloom, once after fruit set and once in the fall. For best results, loosen the soil around the plant by cultivating gently so there’s no root damage. Apply fertilizer uniformly around the blueberry bush’s dripline, but avoid applying it near the base of the plant. This can damage the stems. Apply when the conditions are dry to avoid getting it on the leaves.

Gently work it about 2 inches into the soil. If rain isn’t in the forecast, irrigate. Gardeners should apply enough water to moisten the soil to a depth of at least 2 inches. With proper moisture and fertilizer applied, gardeners should see increased berry size and a boost in overall production.

Fertilizer is applied to grapes in much the same manner but working in a broad circle around the vines. Second-year vines will require a pound of a balanced 10-10-10 fertilizer. In the third and later years, the fertilizer amount is increased to 1.5 to 3 pounds per vine.

Young vines require fertilizer to be split into three to four monthly applications during spring and early summer. For vines already bearing fruit, a single, early spring application is enough.

Gardeners often mistakenly over-fertilize fruit trees. With many backyard fruit trees placed in a lawn setting, the trees unintentionally receive extra fertilizer when the lawn is fertilized. It’s important to pay careful attention to the tree’s nutritional needs when determining the lawn’s fertilizer application amounts. Signs of over-fertilization include limb breakage, poorly colored and soft fruits, and delayed ripening and bearing.

Apples, peaches and plums generally require 1 pound of a 10-10-10 fertilizer per tree per year of age, up to a maximum of 5 pounds. Cherries require about half that amount. Gardeners growing pears should know that they are sensitive to overfertilization. They should limit applications to less than half a pound of a balanced 10-10-10 fertilizer. Too much fertilizer causes weak growth, making it susceptible to fire blight.