ripening grapes on a vine
Updated: February 24, 2023

Mulching and watering grapes

Using mulch and proper watering (if necessary) helps to produce healthy grapes. 

Fertilizing grapes

Soil pH- 5.8-6.5
Year 1- fertilize with 0.30 ounces of nitrogen (N) per plant at planting
Year 2- fertilize with 0.30 ounces of nitrogen (N) per plant at flowering
Year 3- fertilize with 0.40 ounces of nitrogen (N) per plant at flowering
Year 4- fertilize with 0.80 ounces of nitrogen (N) per plant at flowering
Year 5 and older- fertilize with 1.60 ounces of nitrogen (N) per plant at flowering

Fertilizing Fruit

Spray schedule for grapes

  • In most instances, treatments for insects attacking grapes can be delayed until the first evidence of the pests or their damage is found.
  • Black rot is a common disease of grapes in Maryland for both commercial and backyard growers. Preventative fungicide sprays need to be applied in a timely manner. 
  • The same is not true with the diseases caused by fungi. This is because most infections occur 10 to 14 days or more (several months with gray mold blossom infections) before early symptoms are apparent, and each new infection site produces thousands of spores capable of causing other infections.
  • For this reason, once disease begins to appear in the vineyard, an early program of preventative fungicide sprays must be applied each year.

    Fruit Disease and Insect Pest Control Recommendations

    Home Fruit Disease and Pest Prevention Spray Schedule

Harvesting grapes

  • For best quality, bunch grapes should be fully ripe when harvested. Grapes will not improve in sugar content or flavor after picking.
  • As harvest nears, protect the fruit from birds to allow it time to sweeten. Put plastic netting over the vines or small paper bags over individual bunches to exclude birds from the fruit.
  • Cut the bunches off with a knife or shears to avoid bruising the fruit and damaging the vine.
  • Most cultivars should be used immediately, as they do not keep well after harvesting. 
  • Regularly harvesting ripening fruit clusters will reduce nuisance pests such as fruit flies, sap beetles, and yellowjackets.