Nitrogen and potassium are crucial in boosting leaf growth and maximising yield potential and quality.  Too much nitrogen at flowering can restrict flowering and fruit set and yield.  The correct form of nitrogen is crucial for users of ammonium-N sources that can restrict growth and adversely affect quality. 

Phosphorus is crucial for early growth and rooting. It is needed again throughout growth, as it promises higher yields of heavier fruit. Calcium helps with early seedling strength and ensures vigorous leaf development and canopy growth. Magnesium also promotes good leaf growth. Poor availability of any micronutrient will restrict yield. Boron is particularly important at flowering to maximise fruit set.