Potash is a vital regulator in plant growth. It enables plants to
develop strong, thick stems, healthy roots and large, plentiful fruit. Plants require larger quantities of potassium than any other nutrient. Potassium stimulates early growth and hastens maturity of crops.
Potassium is a key nutrient in the plants tolerance to stresses such as cold-hot temperatures. It improves resistance to pests and diseases and is essential for the development of fruits flowers and seeds.
Deficiency symptoms will appear first in the older leaves. These become ash-grey colored instead of deep green, will look scorched at the edges. Plants deficient in potassium often develop weak stem and stalks, small fruit and shriveled seeds along with poor growth and yields. Plants become susceptible to disease .
Adequate supplies of potassium are essential to create vigorous, healthy plant growth.
There are four main types of potassium fertilizers.
Sulfate of potash has the lowest salt index of all major potassium sources, consists of 40 percent potash and is water soluble.
There are two forms of potassium sulfate on the market. One is derived by reacting sulfuric acid with potassium chloride, however it is not acceptable in certified organic production.
Natural or sometimes called organic potassium sulfate, is extracted from natural minerals and is acceptable in certified organic production.
Muriate of potash is a very popular form of potash fertilizer, it is gray in color, consists of 50 to 60 percent potash and water soluble, but has a high chloride content. Some organic certification bodies do not allow the use of this form of potash.
PMS has the additional benefit of supplying Sulfur and Magnesium, Common analysis is, Sulfur, 22.0 percent - Potassium, 18.0 percent - Magnesium, 11.0 percent. PMS does not contain high amounts of chloride, water soluble and acceptable in certified organic production.
Potassium nitrate has 44 percent potash, 13 percent nitrogen, is water soluble but not acceptable in certified organic production.
Only two sources of potash are certified for use in organic agriculture.