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How to Put Wood Ash in Compost

By Amma Marfo ; Updated September 21, 2017

If your garden bed needs a little boost in potassium, or you're having a slug problem, one good source of potash is wood ashes. When you apply wood ash to the garden, use it sparingly, as it can change the pH and salinity of your garden bed. The same is true when you put wood ash in compost, because it eventually ends up in the garden. Collect wood ash from your furnace or fireplace over the winter months, and then work off of it throughout the growing season.

Turn the soil and rotting materials inside your compost bin as normal, using a shovel or pitchfork. Push some material to the outer edges of the composter to form a shallow well in the center for the new material.

Dump your new materials into the center of the composter to fill the well. Sprinkle a handful of wood ash over the surface of the new material using approximately 1/2 cup of wood ash per 3-feet by 3-feet surface area of compost bin.

Draw the older materials in toward the center, away from the sides, and pull it over the new material. Cover the new material and wood ash with the older, still-rotting compost.

Repeat turning the soil as often as desired to keep the bin “cooking,” and add more wood ash only occasionally with every three or four additions of new material.


Things You Will Need

  • Shovel or pitchfork
  • New compost materials (kitchen scraps, leaves, grass clippings, etc.)


  • If you're running a "cold" bin, and not turning the compost on a regular basis, you can simply sprinkle the same amount of wood ash over every three layers. The next layer of new materials covers the previous layer's ash.


  • Allow any freshly spread compost which contains wood ash to rest in the garden bed for two weeks before planting any new seeds to ensure they germinate.