Can wood ash go in your worm bin?
Wood ash from clean, untreated wood can go in the worm bin, but falls into the ‘with caution’ category and must be used with the greatest possible restraint. Wood ash is very alkaline (high in pH) and contains soluble salts. Worms thrive best in a slightly acidic to neutral environment (around pH 6-7). Too much wood ash can drastically increase the pH and increase the salt concentration, which is harmful or deadly to the worms. It can only be useful in a bin that has become too acidic (for example, due to a lot of fruit waste), and even then, only in minimal quantities. Ash from treated wood, coal, briquettes, or charcoal is absolutely unsuitable and should not go in the worm bin due to toxic substances.
How much wood ash can you add?
Add wood ash from untreated wood exceptionally sparingly to your Bonter. Think of a pinch, literally a teaspoon, per large amount of new waste, and only if you have reason to believe your bin is too acidic. Mix this pinch thoroughly with the waste and bedding. Never add more than a minimal amount and do not add it regularly as a standard procedure. It is not a standard part of your worms’ diet or the bedding. Too much is directly harmful.
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What to do instead? Alternatives & waste management
Wood ash is not necessary for a worm bin and carries risks. Unless you are specifically trying to correct the pH of an overly acidic bin with a minimal amount, you can better avoid wood ash. Wood ash from clean wood can be used in small quantities as a soil improver in the garden (also helps increase pH) or added to a traditional compost heap (also here in moderation). Ash from treated wood, coal, or charcoal is dangerous and must go with residual waste.
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Tips for composting wood ash
Use only wood ash from clean, untreated wood. Ash from treated wood, coal, briquettes, or charcoal contains toxic substances and should never go in the worm bin or compost heap. Add wood ash in exceptionally small, sparse quantities, only if you have reason to believe the bin is too acidic. Immediately and thoroughly mix the pinch of ash with a large amount of other waste and bedding. Do not add it as a layer and do not just sprinkle it over the surface. Be aware of the risk; too much is harmful to your worms.
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Frequently asked questions about vermicomposting wood ash
Can wood ash go in the worm bin?
Why can I only add very little wood ash?
Can wood ash help if my worm bin is too acidic?
Can ash from the barbecue or fireplace go in the bin?
What are the risks of too much wood ash?
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