Potash Fertilizer: What Is It and How to Use It?

For the effortless growth and reproduction of your plants, potassium is quite essential.

Once referred to as potash, potassium fertilizers have two main types in which potassium is combined with either sulfate (sulfate of potash) or chloride (muriate of potash).

Potash fertilizer held in a handPin

The name ‘potash’ is derived from the process used to harvest potassium, where it was drained from wood ash and concentrated the leachate using large iron pots through evaporation.

  • Earlier, wood ash was separated into old pots.
  • Potassium was then leached from the mash.
  • It was then called pot-ash.

Even though modern techniques are different from the old pot separation method, the potassium derived is quite useful for animals, humans, and plants.

Potassium is an essential plant nutrient for synthesizing plant sugars and water uptake. It also aids in the movement of water, nutrients, and carbohydrates in plant tissue.



Essential for plant growth, potassium is taken up in large quantities by plants. 

It helps control the exchange of water vapor, carbon dioxide, and oxygen by regulating the opening and closing of the stomata.

Potash fertilizer is found in abundance across the United States. By far, the world’s top potash country is Canada.

It is found in combined forms in the earth’s crust in areas where there are large deposits of heavy soils and clay minerals.

Potash fertilizer is vital for fulfilling all your crop needs.

Even though potash is an active ingredient in many commercial fertilizers, it is crucial to use organic potassium fertilizer, which is usually manufactured with either potassium hydroxide or potassium chloride (KCl).

Hardwood ashes are also a good source of potassium, but you have to make sure to use the plant food in small amounts.

In most cases, potassium sulfate is the most preferred K source over KCl.

Those who would want to go with K2SO4 as a K source are in the right too. However, K2SO4 is more expensive than KCl.

Best Fertilizer for Your Plants

Potassium plays an important role in regulating plant growth. It’s known to be part of the N-P-K ratios on fertilizers, which include nitrogen, phosphorus, and potassium.

The fertilizer application also has a positive impact on the disease resistance of the plant.

It is an organic matter which will help you do away with problems such as K deficiency – also called potassium deficiency – in your plants, which leads to slow growth and leaves turning yellow or brown.

Before planting any vegetable or plant in your garden, it is important to collect a soil sample to carry out a soil test.

Some soil already has sufficient potassium content.

The use of potash fertilizer results in a bigger crop yield.

Potash fertilizer increases the pH in the soil, and this is why it is best not to use it on acid-loving plants such as rhododendron, hydrangea, and azalea.

How to Use Potash Fertilizer

For plant growth, it is important your soil has a sufficient amount of potassium content.

Potash doesn’t move in the soil, so if you want to sprinkle it into the root zone, you have to till it into the root zone.

On average, you should have 1/4 to 1/3 pounds of potassium sulfate or potassium chloride per 100 square feet.

To increase the potassium content in your soil, add wood ash to your compost heap.

In the same manner, using manure is also a good source of potash in the soil.

The component is also quite easy on the roots of the plant.

Besides this, other good sources for potash include greensand and kelp.

There are some things you have to look out for your plant’s health.

If the soil has excess potassium, it will be damaging to the roots.

Since excess potassium accumulates as salt, it is best to limit the fertilizer application to once a year.

Increase the fertilizer application only if the soil is sandy.

This is because sandy soils do not contain organic matter and would need organic matter and leaf litter to increase fertility.

Why Potash Fertilizer is Good for Your Plants

Potassium-rich soil has the following advantages related to plant growth:

  • Increases water retention
  • Improves drought resistance and increases root growth
  • Produce grain rich in starch
  • Creates disease resistance in plants
  • Increases plants’ protein content
  • Prevents energy losses and reduces respiration

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