Ashes in garden... for real?

I throw mine out on my moms garden all winter and it get tilled under in the spring. So far so good. She thinks it helps.

Ash is a good source of potassium and lime and raises soil PH. I use it in the vegetable garden and can also be sprinkled around the stems to keep pests such as snails and slugs away

I dump it in the garden all winter and till it in in the spring. They are hot right out of the stove when thrown into the garden.

KennyK said:

Super helpful, especially as I have some rhododendrons I would definitely not want to hurt, and some lilacs that will be getting a treat today! So, from what you wrote it sounds like that ash makes the soil more alkaline - correct? Also, when you say soil that has been heavily limed, would that just be if I added lime to the soil, or might that be naturally occurring?

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Before you adjust your soil, get a pH test kit so that you know your conditions. Yes, lime makes it more alkaline.

People can add lime, it can leach from foundations and sidewalks, and it can be naturally occurring.

We like to say that we live on a limestone cliff (which has also been overgrazed by the previous owner’s animals).


Our previous home in Virginia had much more acidic soil. Test your conditions, research the plants you have or want to grow, and calculate amendments from there.

I shouldn't be too surprised to find that some wood burners also garden!

I'm a fan of wood ashes on the garden - one is to adjust my slightly acidic pH from the low 6's to something around 6.5 or slightly above, the other is the trace minerals in the wood ash. Just think - if you are burning some oak from a 75 year old tree, those deep roots have been gathering minerals for that whole time and gathering them from forest soil, not worn out crop fields.

We all have our moisture meters ... I think that a pH meter can be just as necessary for a gardener. There's the model I have:
https://www.jungseed.com/P/51326/Digital+Ph+Meter

There are numerous meters on the market. Much like our moisture meters - the device needs to measure between two contacts. You'll see most pH meters with two "probes" that you stick into the soil. The model that I have only has 1 - so how does it work? The very tip is separated by a non-conductive section of plastic from the rest of the probe. So it looks like one, but is really two.

I put some of my wood ash on the garden and then stop at some point. After I till in Spring, I'll check with my meter and know how close I got. Then I'll either add some more in the coming year or not depending on if I'm in my desired pH range.

Another place to go with ash is your lawn. Most lawn soils are too acidic, so wood ash and or lime can really help the health of your lawn.

Of course all of this is based on knowing what your soil pH is.

KennyK said:

Wow XmasTreefarmer, super helpful! Clearly you are a pro! After following advice here, I'm anticipating that having a new wood stove is going to have some secondaries beyond just in the fire, but a secondary effect of making my garden happier, healthier and more beautiful!

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Glad I could help! I just PM'ed you some additional info.

Wood ash does help lawns and gardens; just throw it out scattered and the melting snow and rain does the rest. Walnut ashes though can damage grass, something toxic in the ash for grass plants. I wouldn't know since all mine go under pine trees where grass won't grow anyway.

Ashes are loaded with minerals. You may read that some vegetable contains a high amount of a certain mineral. Sure, it does, in the natural state, but, if the farmer has been growing the same crop on that land for 50 years, the minerals are depleted.
Farmers add N,P, and K, that is regular fertilizer. But they don't add minerals.

So you are doing yourself a big favor if you add wood stove ashes to the garden.

I need to check into biochar as well, ground charcoal added to soil. Supposed to be good but I don't know what it does..

I put most of mine around my olive trees close to the trunk as they have a small root ball. Some I add to my compost bin along with peelings and biodegradable kitchen waste.

I've read that one can use wood ashes as lime if you figure that you need 2.5 times the amount of ashes as lime.

Last year I put a winter's worth of ashes on my garden last year. I made the PH a bit too high, so this year I'm holding off. I will be holding a 35 gallon trashcan in reserve in case my soil has acidified. I've been spreading some on my yard as well.

Have you ever seen a forest floor the Spring after a fire?

Ablaze with healthy plant life!

Dave

I spread it on the lawn. Seems to like it...

begreen said:

Been studying biochar for a few years now and have a research garden testing it. The amount of research and papers on biochar have gone up dramatically in the past 5 yrs.. It has great promise when used properly.
http://biocharfarms.org/

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Thanks begreen - Had never heard of biochar - have been checking out their website and learning a lot. I'm always looking for ways to enhance what I'll call "the total soil health" of my garden space.

Wonder how it would affect the plant species we are now allowed to grow here in Vt this summer.

Rearscreen said:

Wonder how it would affect the plant species we are now allowed to grow here in Vt this summer.

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Those plants like a PH 6-7 range...so save it for the plants that benefit from ashes

My stove doesn't let coaIs of any size through the ash grate, but in-laws have stoves they shovel out. One puts her ashes/coals in a pile after they chill in a steel bucket for a good while. Seems like the rain has rinsed some of the ash away from the coals but I haven't dug into the pile yet to see if the coals deeper are pretty clean of ash. I haven't thought much about how I might pulverize the coals yet, but an old blender sounds like fun. Depending on how much you need per square-foot area..

XmasTreefarmer said:

Thanks begreen - Had never heard of biochar - have been checking out their website and learning a lot. I'm always looking for ways to enhance what I'll call "the total soil health" of my garden space.

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There was a biochar pilot plant in Gorham Maine about 10 years ago, they pyrolyzed the wood and then collected the volatiles and turned them into chemical feedstocks. The principal engineer ended up working for the facility up in Old Town Maine that is now aligned with University of Maine.

The archeological studies on Terra Preta soils that have a biochar base is pretty fascinating. Finding an old bed is a quick way to make a buck despite it being thousands of years old.

If there ever is a carbon market I expect folks will modify biomass power plants to pyrolyze the wood into biochar and then burn the volatiles to generate power. If the carbon market is good enough they will bury the biochar and sell the sequestration rights as once the char is in the soil, it takes a long time to get back in the atmosphere. There was an entrepreneur in VT trying to sell carbon sequestration rights by adding manure to topsoil. I dont think it was a viable business model as the carbon didnt seem to stay bound to the soil. I expect biochar would be far longer lasting

Note that biochar acts like a sponge, it needs to be loaded up with the right soil nutrients or it will actually reduce the nutrients available to the plants growing in it. If you study Terra Preta, they reference finding broken pottery, fish bones, and other organics and crop residues. The concept is that the organics break down and the biochar absorbs the nutrients and then make them available over the long term to the crops. I think the concept is that once the nutrients get trapped in the biochar matrix they cant get leached out. To me it is very similar to composting but amended with biochar to make it longer lasting.

The hassle with making biochar is the wood has to be quite dry or pre-dried prior to the pyrolysis or the volatile stream gets overloaded with water vapor. If the wood is pre-dried the exhaust flow is loaded with VOCs and has to be treated with a regenerative thermal oxidizer. Home brew operations can get away with a lot but if it goes commercial the initial investments and operating costs makes it not worth building. Ensyn makes "bio oil" using a rapid pyrolysis method, they turn the volatiles into "bio-oil" and use the char to fire the process. Its expensive to make and is only stable for a few months before it breaks down but qualifies for lucrative bio fuel incentives.

Note the holy grail for the wood pellet industry is effectively partially pyrolysed wood with enough lignins left in the mix to bind the char and make the pellets waterproof. The resulting pellet is getting close to coal on a btu basis without the heavy metals inherent in coal. There have been a couple of startups who claimed to be able to make these pellets but the last one gave up after several years in Millinocket Maine. Zilkha Biomass claimed to be able to make similar pellet but the reality was it was closer to Masonite pellet, better than a standard pellet but a big step below a biochar pellet.