Increasing wine grape berry set and weight

Nitrogen 

Trials show that applications of nitrogen at flowering increases wine grape berry set. High rates of N will increase wine grape yield. In work by Nielsen et al, N yield responses hadn`t peaked at applications of 300kg/ha and there was a similar correlation with grape bunch weight in two out of three years of this trials.

Phosphorus

Most of the phosphorus comes from soil reserves as grapes are good at extracting phosphorus from the soil. Phosphorus is also very mobile in the vine. Where phosphorus is naturally low in soils, applied fertilizer phosphate increases wine grape berry set and crop yield.