Potassium activates plant enzymes and keeps cell fluid movement in
balance. Potassium regulates water loss through stomata (tiny pores) on
the leaves, and it is necessary for root formation and food storage in
the plant. Severe deficiencies in vegetables can appear as deformed,
stunted or yellow leaves, weak stems and premature fruit drop.
This corn shows severe potassium deficiency in the stunted, yellowed
leaves. Stalks lack strength and fall over late in the season.
Poor flesh development in the two tomatoes on the left is caused by
potassium deficiency. The two fruits on the right show normal
development.
Potassium deficiency in young tomato plants results in
deformed stems and leaves, browning in older leaves, ripe fruit falls
off
vines.