Working with wood ash
1 You can sprinkle your wood ash directly onto the soil around crops that might appreciate its potash content. Pass it through a coarse riddle to remove large lumps, then add at a rate of 50g per square metre, gently forking it into the upper 8in (20cm) or so of soil. 2 The potassium in wood ash is very water soluble, so ideally you should use it within a few days of being created (especially if heavy rainfall is due, as this could leach out the ash’s nutrients). Plant roots will then readily take it up before entering their winter dormancy. 3 Wood ash is generally quite alkaline (the opposite of acidic) so it’s best used around crops that are happy in soil with a neutral or slightly alkaline pH value (pH 7 or above). Avoid using it on acidloving crops such as raspberries and blueberries.