The term potash is literal – pot and ash – derived from the Dutch potaschen. It refers to the process of soaking wood ash in iron pots to dissolve the potassium salts and then evaporate them. Up until the 19th century, potash was very important, and used in glass, ceramic and soap-making, as well as fertiliser.
Potassium is a macronutrient, meaning plants use a lot of it during their growing cycle. It is involved in many processes, from photosynthesis to aiding the correct uptake of water and nutrients. It is vital that you burn only organic matter such as logs and newspaper; coal and plastic will poison your soil. As the potassium is water-soluble, it’s quickly leached out by rain, so once the fire has cooled, collect and store the wood ash.
This can be used in several places. If you have onions and garlic coming up, then a thin dusting between the plants is ideal. You can also store the ash for spring, where it has value for apples, currants, gooseberries and the like. Spread it around their bases and the rain will do the rest. There is little point spreading it over bare ground as with no plants to sup it up, it will just wash away.
If you don’t have the space to store the wood ash, add it to your compost pile, which can absorb no end of the stuff. Being an alkali, it will sweeten the contents of the bin that naturally errs on the acid side.
- Which is involved in potash?
- What makes potassium an important nutrient for plants?
- Why are plastic and coal not recommended for potash?
- Why is it pointless to spread the ash on a bare ground?
- What does an alkali do to plants?