Potassium And Soil
(Potash Fertilizer)

What Is Potash Fertilizer?

Potash fertilizer is the commonly used term for the soil fertilizer forms of potassium (element K). The name comes from collection of wood ash in metal pots when the fertilizer benefits of this material were first recognised many centuries ago.

Muriate of Potash

It's odd how this old-fashioned name remains in use! Muriate comes from Muria, the Latin for brine. Muriate of potash is potassium chloride containing between 50 and 60 per cent potash. It was deposited eons ago by ancient seas and should be considered a natural product, blessed by organocultists, but it is not. Its chlorine content passes off rapidly when applied to soil.

As explained under soil organisms, however, muriate of potash is harmful to certain beneficial bacteria. Some authorities think sulfate of potash makes a better potash fertilizer.

Sulfate of Potash

This contains 48 per cent potash. It is more expensive than muriate of potash but is considered less harmful to bacteria and plant roots.

Wood Ashes

About the only generally-available organic source for potash fertilizer, this material is treasured by organic gardeners.

Wood ashes contain about 6 per cent potash, plus considerable lime.

Before corn cobs were used industrially, the cobs were burned in huge piles. The resultant ashes were peculiarly rich in potash - up to 35 per cent.

Almost any ash resulting from burning organic materials that contain some fiber should be a fair source of potash fertilizer.

Wood ashes are particularly good to use for adding potash to a compost heap.

Learn More About Soil Fertilizers & Additives:

Chemical Nitrogen In Soil - understanding nitrogen in soil, and how it is used to make fertilizer products.
Fertilizer Formula - feeding rates of various fertilizer formula.
Organic Nitrogen And Soil - organic forms for getting more nitrogen into your soil.
Phosphorus And Soil - phosphorus is vital to your soil of course. But bone meal is so overrated.
Fertilizer Costs - calculating the REAL cost of fertilizer.
Mixed Fertilizers - the gardeners preference, so what do NPK values refer to?
Fertilizer Burn - how to avoid burning your plants/lawn with fertilizer.