QUESTION: How much ash should I put in my compost?
ANSWER: Ashes from burning wood in a fireplace contains important nutrients such as calcium, potassium, and magnesium, all of which were present in the original wood. Ash can be added to your compost pile as a brown carbon-producing material to balance out green, nitrogen-producing materials such as kitchen scraps and grass clippings.
Use ashes in moderation in your compost, however, because no matter how nutrient rich ash may be, it is also highly alkaline, so it can help raise the pH of acidic soils, but can otherwise throw off the pH balance in your compost and eventually, your amended soil. Follow the following instructions to add fire ash to your compost heap.
First, grab a soil pH test kit from your local garden center or nursery in order to determine the pH balance of your soil before adding wood ash to your compost. If your soil is alkaline, with a pH over 7.0, it’s a bad idea to add wood ash to your compost.
Keep an eye on the weather conditions and pick a day with no heavy wind gusts so that the ash won’t blow and scatter away into the air before you can get it into the compost pile. Put on a pair of gloves, a face mask, and goggles, or some other form of eye protection when handling ashes, as the tiny particles from ash can easily be inhaled, and the high alkalinity of the ashes can irritate your skin
Using a shovel, place the ash in a bag for transporting it to the compost pile and gather up the other materials that are ready to add to the compost. Keep in mind that a healthy compost balance consists of three times as much brown material (brown leaves, newspaper, clean cotton rags) than green material (grass clippings and kitchen scraps).
Layer the compost heap with alternating layers of green and brown materials, adding in wood ash at the same time as your brown layer. Don’t place more than a ⅛ inch layer of ash into each nine inch section of brown compost materials, and be sure to alternate your brown layers with three inch layers of green material to keep a proper balance of carbon-producing and nitrogen-producing materials.
Adding too much ash can be harmful to the compost due to its alkalinity. Turn your pile with a shovel or garden fork everytime you add new items to your compost and make sure that each addition of ash is partnered with a full nine inch layer of brown materials to balance the alkalinity of the wood ash.