Purpose of Potassium:
Cause of potassium deficiency:
Insuffiecient K in the soil.
Sand soil or limestone usually happen as water easy leached away.
Potassium deficiency can be extremely similar with manganese deficiency from a distance. But close examination should reveal characteristic spotting and marginal necrosis in K deficiency or necrotic streaking for Mn deficiency.
Potassium deficiency symptoms are more severe toward the leaf tip and less so at the leaf base. Mn is opposite of it.
Symptoms of Deficiency:
When applying K fertilizers to correct an existing K deficiency, it is important to also apply about 1/3 as much Mg (also in a slow release form such as prilled kieserite) to prevent a high K:Mg ratio from causing an Mg deficiency problem.
For severely K-deficient landscape palms, broadcast this 3:1 blend of sulfur-coated potassium sulfate and prilled (prill – a pellet or solid globule of a substance formed by the congealing of a liquid during an industrial process: the consistency of fertilizer prills has a major effect on nitrogen application) kieserite uniformly to the soil under the canopy at a rate of 1.5 pound per 100 sq ft of canopy area.