How To Use Wood Ashes In The Garden

I’ve had a number of people over the years ask about using wood ashes in the garden. While they are a source of potassium, ashes are highly alkaline (high pH) – similar, in fact, to household bleach, believe it or not.

We’ve always just added our ashes from heating our home in the winter to our compost pile, which is a slow, “cold” breakdown at our place. Meaning- we don’t mess with our compost- we simply make a pile of house and garden debris, layered with some leaves and shredded paper, and when it gets big we start a new pile and let that one decompose on it’s own over time. We might mix it once or twice, but that’s it.

For those who’d like to add it directly to the garden, or who have more ashes than we do (we don’t heat exclusively with wood), here are some tips and precautions for using wood ashes in the garden:

  • Apply recommended amounts to moist soil and rake lightly to mix, remembering to wear protection. Optimal amounts can be determined by a soil test, but usually a 5-gallon pail over 1,000 square feet is considered safe. With ashes, it’s always better to add less rather than more.
  • Use ashes from regular wood only- not treated wood or trash, which can contain substances that will inhibit plant growth.
  • Don’t use wood ash where potatoes will be planted.
  • Since it’s alkaline, don’t spread ashes around acid-loving plants such as blueberries, azaleas, and rhododendrons.
  • Always rake or mix ash in – if left in piles, excessive salt from the ash can leach into the soil.
  • Also, wait until after seeding to rake ashes in- ash contains too many salts for seedlings.
  • For a lawn, wait at least a month after wood ash application before applying nitrogen fertilizer to allow time for the soil to reduce the alkalinity of the ash.

For more information about using ashes in our yards and gardens, visit the OSU Extension Service website.

Do you use ashes in your garden? Do you think they’re helpful or harmful?






  1. Anonymous says

    I use just a little from burning fallen limbs in the back yard. So, I’m thinking the fallen pine needles are acidic and if ash is alkaline, then blending in the ash could make a neutral, if you knew the right proportions. Does this sound right? No need to buy bags of anything?

    brenda from ar

    • Jami @ An Oregon Cottage says

      You’d need a nitrogen source, Brenda, and probably a few other things like phosphorus. Best to get a soil test and find out if you wanted to mix your own. I usually add well-done compost and a balanced organic fertilizer and call it good.

  2. says

    I don’t have a fire place, but just the picture got me excited for gardening. I am so over winter, bring on spring. I almost bought garden seeds the other day just hoping it would magically change the weather and let me play in the dirt. I feel like a kid waiting for Christmas.

    I started a small compost pile, but I don’t know what to do with it. Do I need to add anything to it? Right now it’s covered with snow, but Im hoping when it clears the pile has turned into something usable.

    • Jami @ An Oregon Cottage says

      The start of a new season is always the best, Sakura! For our compost that we just let decompose naturally, it usually takes about 9 mos. to a year. There’ll probably be some “black gold” at the bottom of your pile, though, in spring. :-)

  3. says

    Actually I use our ashes (we get tons as a wood stove is our main source of heat)as a weed suppressor. We pour them out along the edges of our property where I want nothing to grow. It works great and come spring it is one area I do not have to weed. I keep the ashes a good 6 inches back from any area I do want to grow things.

  4. Thoughts for the day says

    We do put our ashes in the garden along with other ‘throw away food items’. Did not think of putting it where we don’t want weeds. That is a great idea.

  5. Mary W says

    I don’t put ash in my garden because So Cal has naturally alkoline soil so any ash would be too much. But the weed trick sounds great.

  6. says

    I have a hard time getting my compost pile to turn to compost. It is really dry here and the pile tend to dry out. Last year we bought red wiggler worms and added them to the pile. It is amazing how fast they ate it. It wasn’t a hot pile, worms doen’t like the heat. So far they had lived through the winter also, but our winters are somewhat mild. So glad i tried it. They aren’t in a box so if the pile gets too hot or cold they can go down into the ground.

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>