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Using wood ash in the garden

Did you know you could be using wood ash in the garden to deter pests and disease and build your soil? You can! Learn the do's and don'ts before you start.

A few weeks ago I was walking the garden with a friend. My friend happens to be from Kenya and I’ve learned so much from her over the few years she and her family have been in the US. My large kale plant had an aphid infestation and I don’t know about you, but aphids are hard for me to get rid of. Partly because I’m not as diligent as I should be and partly because I’m scared to use anything on my plants that *might* hurt the bees. So, I usually do nothing.

I asked my friend what they do in her country for aphids and she said they sprinkle wood ash on the plants. Really??? Using wood ash in the home garden was new to me. So the next evening, I got some ash from the smoke belly of our smoker and sprinkled some on the kale and the green beans that were next to them. I noticed that the pill bugs – we have an infestation right now – didn’t like the ash and were running from it. The next day, there was a noticeable reduction in aphids on the kale and green beans. I don’t know if they just left and took up residence somewhere else or if they died but my interest has been piqued.

Want to know what I’ve learned?

Let’s start with the Don’ts….

  • Ash is alkaline so don’t use it on acid loving plants like blueberries, azaleas, mums, pecans, oak, mountain laurels, sweet potatoes
  • Don’t use wood ash on regular potatoes – it might encourage potato scab
  • Don’t use ash on seedlings because there is too much salt in it for them
  • Don’t use ash if you already know your soil is alkaline – if you’re unsure you can have it tested
  • Don’t use ash from anything other than just wood – no charcoal or briquettes, no plastic or styrofoam, no fake wood from the fire place, etc.
  • Don’t use ash from burning treated wood

Now the Do’s…

  • Sprinkle ash on and around plants to deter pests. The ash tends to suck the water out of the insect, they don’t like that
  • Put a ring of ash around plants to keep slugs away
  • There are some plants that just LOVE wood ash; plants like tomatoes, broccoli, collards, lilacs and roses
  • You can add wood ash directly to the compost bin – just don’t overload it or you’ll mess up your mix
  • Sprinkle over your lawn as a fertilizer

Obviously, I wouldn’t go around just burning tree limbs to get wood ash, but most of us have a fireplace – either inside or out- that we can get wood ash from to use in the garden.

Another thing to point out is that when it rains, the wood ash has to be reapplied to deter pests.

One last thing, my son read that wood ash will help keep algae from growing in water. A little goes a long way here, you only need 1 Tablespoon to treat 1000 gallons of water.

So, as you’re cleaning out those fireplaces or having campfires this summer, don’t throw away the ashes, use them to have a great garden this year.

Lastly, it’s a good idea to keep notes on your observations of using wood ash in the garden. I keep a gardening notebook that is now full of information about what has worked and what hasn’t in our garden.

Did you know you could be using wood ash in the garden to deter pests and disease and build your soil? You can! Learn the do's and don'ts before you start.

Do you you use wood ash in the garden? Let us know in the comments so we can all learn.

Thanks for sharing with your friends!


Saturday 19th of June 2021

My grandmother used wood ashes sprinkled thru an old hose (think panty hose). On beans to get rid of beetles. The mixture was a peck of wood ashes filtered thru a wire strainer to a half cup of salt (or I quart to a tablespoon for my much smaller garden). It works and I just set up my recipe today to be ready.

Angi Schneider

Sunday 20th of June 2021

Thanks for the tip!

Burn Barrel 101: Why You Need One on Your Homestead

Tuesday 24th of November 2020

[…] is one of those times I don’t condone composting. Ash is, in moderation, great for the garden, but unless you’re burning straight wood in your burn barrel… maybe not this time. I […]

Sharad Sharma

Friday 24th of August 2018

Yes I use ash on my plants. It's a very old technique followed by se people here in india. It's too popular. Many people are using ash left from burning cow dung cakes. I have collected ash from burning dried leaves of neem tree. This time I have used it on my plants at terrace and results are too good I can suggest one more item for farming which is self made and costless. We call it jeevamrut. It's a good fertilizer.

Angi Schneider

Friday 24th of August 2018

Hi Sharad, it's really great that your people are really utilizing what's available for fertilizer. Here in the states I think most of us (myself included) don't realize how wonderful those fertilizers are and instead spend money on purchased fertilizer and pesticides. I looked up jeevamrut and it looks amazing - I'll have to see if I can locate some local cow dung to try some. Thanks so much for sharing what you do!

Simone clark

Sunday 7th of May 2017

What is the difference between wood ash and sulphate of potash in its composition and effects on vegetables?

Angi Schneider

Monday 8th of May 2017

The main differences are going to be cost and precision. If you use ashes from wood you burned, it's free but you won't know the exact percentage of potash or potassium in it. If that doesn't bother you to not have that precision, I would just use wood ash. On the other hand sulphate of potash costs money but the bag will tell you what percentage of potash and potassium are in it. If you need that specificity or don't have access to wood ash, then use sulphate of potash. The effects of using either one are going to be very similar.


Friday 7th of April 2017

Even in an alkaline soil wood ash is great for spring flowering bulbs ..tulips,daffodils, crocus..

Angi Schneider

Friday 7th of April 2017

Thanks for sharing, Elaine. I'm not much of a flower gardener and didn't know that.