Potassium deficiency, also known as potash deficiency, is a plant disorder that is most common on light, sandy soils.Potassium deficiency is also common in chalky or peaty soils with a low clay content.
Potash is a complete nutritional supplement given to crops. This leads to the all round development of all types of crops
Tuber size is much reduced and crop yield is low. The leaves of the plant appear dull and are often blue-green in color with interveinal chlorosis. Leaves will also develop small, dark brown spots on the undersides and a bronzed appearance on the upper surfaces.
The stems are woody and growth is slow. Leaves are blue-green in color, and the interveinal area often fades to a pale gray color. Leaves may also have a bronzed appearance and yellow and orange patches may develop on some of the leaflets. Fruits often ripen unevenly and sometimes have green patches near the stalks.
Leaves are scorched around the edges, and interveinal chlorosis is common. Apple fruits often have a slightly acidic or woody taste.
Dieback of shoots and branches is common and although the plant may produce many blossom buds in the early stages of deficiency, fruit yields turn out low and the fruits are of poor quality.