Potassium deficiency-Potatoes

Symptoms
Edges and tips of the lower leaves become yellow and later necrotic. Eventually, the marginal yellowing spreads between the veins as the deficiency progresses. Leave margins curl up. The leaves often wither and collapse prematurely. Plant growth is squat and stunted.

Reasons
Potassium deficiency

Symptoms
Potassium deficient tubers show black spots. When cut, they blacken rapidly. The spots mostly occur near the vascular ring at the stolon end of the tuber.

Reasons
Black spot due to potassium deficiency

Symptoms
Edges and tips of the lower leaves become yellow and later necrotic. Eventually, the marginal yellowing spreads between the veins as the deficiency progresses. Leave margins curl up. The leaves often wither and collapse prematurely. Plant growth is squat and stunted.

Reasons
Potassium deficiency