Nearly all plants benefit from the potash content of wood ashes. [1] X Trustworthy Source Royal Horticultural Society Leading gardening charity in the U. K. providing resources for identifying, growing and caring for flowers and other plants Go to source Other components of the ashes are beneficial to the soil and plant growth as well. Because the wood ashes act as a liming agent, they reduce the acidity of the soil. [2] X Research source Plants that prefer acidic soil such as blueberries, azaleas or rhododendrons will not thrive if wood ashes are applied.
The ashes contain a good amount of lye which is a caustic agent. For this reason, refrain from placing them on young tender plants. Wear gloves when handling the ashes. Use a mask to avoid breathing in the residue and protect your eyes with sunglasses or goggles. Avoid using ashes from cardboard, coal or painted wood. These substances contain chemicals that can be harmful to your plants. Monitor your soil to be sure it hasn’t become too alkaline. Use a soil testing kit to check the PH levels or take a soil sample to your county extension office lab to be evaluated. [5] X Research source Alkaline soil will need sulfur added to it.
