What Kind of Fertilizer on Muscadines?

Fertilizing Young Vines

• A balanced fertilizer of 10 parts nitrogen, 10 parts phosphorus and 10 parts potassium is appropriate for muscadine grapes. When they are first planted in the ground in spring, apply a quarter pound of fertilizer in an 18-inch circle around each vine. Repeat application every six weeks until summer, at which point the amount should be doubled to a half pound per vine. During its second spring, apply a half pound of fertilizer in March, May and July. Sprinkle 2 to 4 ounces of Epsom salts to incorporate magnesium if a deficiency is suspected in young vines.

Fertilizing Mature Vines

• When vines are mature, apply 1 to 2 pounds of 10-10-10 under each vine in mid-March and mid-June. If the vine is growing more than 3 or 4 feet during the season, reduce fertilizer by 20 percent the following year. Fertilizer will have a direct effect on growth rate and can be adjusted to produce desired vigor. Applying 4 to 8 ounces of Epsom salts to each mature vine can cure magnesium deficiency. To avert boron deficiency, which can occur in sandy soils, mix in 2 tablespoons of Borax with fertilizer.

Tobacco Fertilizer

• Some growers have successfully used tobacco fertilizer to feed their muscadines. This fertilizer contains six parts nitrogen, six parts phosphorus and 18 parts potassium, as well as micronutrients that prove beneficial for the grapes. Apply as you would a 10-10-10 fertilizer, providing a quarter pound for young vines, and increasing amounts as the vines age. Also, 6 to 7 ounces of calcium nitrate should be applied in May.

Tips

• For best nutrient absorption, adjust soil to a pH of 6.5 before planting. Avoid applying mulch that will break down into nitrogen late in the season, as this can lead to freeze damage. Those in climates susceptible to winter cold can skip the July fertilizing. Do not apply fertilizer too close to the trunk, as most nutrient absorption does not occur there.