Potassium deficiency made worse by
- Acidic soils (low pH)
- Sandy or light soils (leaching)
- Drought conditions
- High rainfall (leaching)
- or heavy irrigation
- Heavy clay (illite) soils
- Soils with low K reserves
- Magnesium rich soils
Potassium is important for
- More new growth in spring
- Leaves usually larger, greener and retained
- Fruit set increases
- Fruit larger with better colour and acidity
- Overall yield can increase, cold hardiness increases