Whether they come from your chimney or from the destruction of plants after the autumn cleaning of the garden, wood ashes can be recycled. A very natural way to amend the soil and compatible with organic gardening.
Wood ashes are very rich in mineral salts, they contain calcium, potash, silica, magnesium and phosphorus. It is a source of food for plants and cannot harm them because it is easily assimilated. There is no risk of overdosing the plants and no risk of polluting the water table.
Potash favors the development of flowers and fruits, so it can be spread at the foot of fruit trees and bedding plants in spring or at the foot of citrus trees in autumn to support flowering and good fruiting.
Wood ash is also very useful to fight against gastropods: you just have to form a cordon of ashes around the young seedlings to prevent them from attacking them greedily. To be effective, you must repeat the operation after each rain!
What type of ashes to use?
Only use ashes from the combustion of plants or untreated, unpainted and unvarnished wood, otherwise you risk contaminating your garden with toxic substances that you will inevitably find on your plate when you eat your fruits or vegetables!
Also be careful not to burn plastics, which are dangerous for the environment and for the atmosphere, nor plywood, composite wood or OSB panels which contain abundant glues and chemical resins.
That said, any healthy, natural and untreated wood species will make a perfect fuel, as well as garden waste such as prunings, dead leaves, mown grass…
How to proceed ?
Always wait until the ash has cooled down and then sift it, as large residues will not decompose quickly enough and will not be assimilated.
The spreading will be done directly at the foot of the fruit trees just under the crown.
For beds, spread the ash on the surface and then lightly scratch it into the soil.
If you want to save the ash for use the following spring, sift it and store it quickly in waterproof bags under cover until you can use them.
Be careful not to overuse the ashes at the feet of the heather plants because they contain mostly calcium which modifies the PH of the soil, making it alkaline and therefore not very favorable to the culture of these plants which would then risk developing chlorosis.