Potassium deficiency (plants)

This article is about potassium deficiency in plants. For potassium deficiency in humans, see hypokalemia.

Potassium deficiency, also known as potash deficiency, is a plant disorder that is most common on light, sandy soils, as well as chalky or peaty soils with a low clay content. It is also found on heavy clays with a poor structure.

The deficiency most commonly affects fruits and vegetables, notably potatoes, tomatoes, apples, currants, and gooseberries, and typical symptoms are brown scorching and curling of leaf tips, and yellowing of leaf veins. Purple spots may also appear on the leaf undersides.

Deficient plants may be more prone to frost damage and disease, and their symptoms can often be confused with wind scorch or drought.

Prevention and cure can be achieved in the shorter term by feeding with home-made comfrey liquid, adding seaweed meal , composted bracken or other organic potassium-rich fertilisers. In the longer term the soil structure should be improved by adding plenty of well rotted compost or manure. Wood ash has high potassium content, but should be composted first as it is in a highly soluble form.

Other physiological plant disorders include:

• Boron deficiency
• Calcium deficiency
• Iron deficiency
• Magnesium deficiency
• Manganese deficiency
• Nitrogen deficiency
• Phosphorus deficiency