In general, grapes are not heavy feeders. The amount of fertilizer needed depends on the type of grapevine and the type of soil where the vine is planted. Follow general rules of fertilizing for most grapes, but if you are having problems with the vines, leaves or fruit, contact your local extension office and inquire about soil sample testing. Well-maintained and fertilized grapevines produce fruit for up to 40 years.
Apply 4 ounces of 10-10-10 fertilizer in a band forming an 18-inch-diameter circle around the base of a newly planted grapevine, keeping the fertilizer at least 6 inches away from the trunk. Water well to soak the fertilizer into the soil. Planting should take place in April or early May.
Repeat the application every six weeks through June in areas that have early freezes or through early July in more southern locations. These applications are for the first growing year.
Spread 1 pound of fertilizer per vine evenly to the soil in the early spring of the second growing year and 1.5 pounds during the third year and thereafter. Increase the diameter by 2 inches while increasing the space between the fertilizer and the trunk 2 inches. This is due to the trunk getting thicker and the roots spreading farther from the trunk.
Sprinkle 2 to 4 ounces of Epsom salts on the soil per vine for the first three years and 4 to 6 ounces per vine thereafter. This will prevent a magnesium deficiency in the plants and correct a deficiency in older plants.
Counter boron deficiency in sandy soil by mixing 2 tsp. of borax with the amount of fertilizer required for the mature vines of 400 square feet.
Remove any nitrogen-rich mulch by late June. Otherwise the mulch may encourage late-season foliage growth that will be damaged by frost. Mulch may be reapplied in early spring.
Things You Will Need
- 10-10-10 fertilizer
- Iron chelate
- Zinc foliar spray
- Epsom salt