Stone Fruit
Phosphorus and calcium sprays have a direct effect on fruit colour, increasing the levels of anthocyanins in the skin, and thus improving crop marketability. Phosphorus sprays applied to the fruit two to three weeks prior to harvest are particularly effective in improving the colouration of peaches, apricots and plums.
Also potassium has been found to improve the red colour formation on the skin of peach fruits.
Overuse of nitrogen can reduce fruit colour, leading to lighter colour, peaches and nectarines.