Baking soil?

SprigOfTheLivingDead

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In Arkansas I'd burn in the garden every winter. Scraps of wood from the workshop, limbs I picked up throughout the year, and mostly prunings from the fruit trees and some blackberry briars. I'd get a big pile of wood ashes that I'd scatter over the garden, plus any "charcoal" left. It would sterilize the area right under the fire, not sure how far down it reached. I suspect not real deep. It would burn up any organic matter in the top of the soil, not good. But when I cleaned it up and got ready to plant I'd add a bunch of extra compost to that area and till it in. I can't say that area grew things any better but it wasn't worse than other parts either.
I know the wood ash is good for the soil, so that probably helped
 

digitS'

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It can be, Sprig'.

However, it isn't always best for every soil, or not right away. Later in my gardening career than I should be willing to admit, I had this idea that onions would gain special benefit from potassium. I had begun heating with wood again and there was about a 100sqft bed of onions that I'd just planted.

In my crude experiment, I covered half of it with wood ash. Within a couple of weeks and right up to harvest, it was obvious that it was a mistake. What I hadn't realized at the time was how high the pH of our soil was and how few garden vegetables would appreciate boosting that pH with ash.

Later, I had reason to check the pH of community well water on a regular basis. Zounds. By late summer, the pH regularly climbed above 8!

I began to just add ash from my wood stove to that acidic mix of compostables that I applied to the garden after it had some time to decompose. That turned out to be a good place for it ... I still had to be sure that the ash cooled first ;).

BTW, ash from manure is used worldwide as a fertilizer (maybe, in lower pH soils). If you have to carry fertilizer on your back from the village to distant gardens, it makes some sense to burn it. Caution here again :): we had a manure pile on the farm just outside the corral gates. Once, we piled some old boards near the pile and accidentally set the manure pile on fire. Oops. There was one very stinky haze of smoke that hung around the barn and corral for several days after that! Loading it on the manure spreader would have been a good deal better use for that manure than setting it on fire!

Steve
 

Dirtmechanic

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It's this balance of life that I am hoping for.

Infected seed? That sparrow, that showed up on the deck and ate some of my tomato seed - what was he carrying? I don't want a sterile environment for the plant starts but, yes, the organisms are both cooperating and competing. My bet is that there is a great deal of competition but that with some of the life, the seedlings can both tolerate it as neighbors and some, gain benefits. Some of the activities, the seedlings will just shrug off because of their youthful vigor, others may well overwhelm them.

I'm a believer in the benefits (& risks) of fresh air and sunshine. That's part of the reason I'm happy to have the little backyard greenhouse. And, I'm happily willing (nearly ;)) to put up with the attention it requires during the spring.

I wish that there was some magic elixir that I could spray over the plants to establish them within a balance of life that would benefit them. Perhaps there is but I will treat any news on it with skepticism. However, until some great drama occurs in my kitchen, South Window or greenhouse - I will rely on experience. Dearly earned, I might claim but, really, I haven't had many problems with plant starts. Probably, there has been lots of dumb luck involved.

I'll say something about my limited experience with cuttings. Good Heavens. I'm injuring the plant! An open wound ... antiseptic, bandage, sterilized environment!! No, I have to allow for the cuttings' life processes ... I have used either sterile starting mix or 100% perlite with my cuttings (along with rooting hormone). Worked! In about 9 outta 10 experiments. And, that's what they amounted to, crude experiments that mostly turned out okay.

Steve
Ya know this quarantine thing is making for a lot of really good posting!
 

flowerbug

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How about burning sticks and wood on TOP of your garden bed?
a waste of energy and nutrients... burning sends all that energy into the air when it could be going towards the soil community instead. a certain amount of wood ash and charcoal is ok, but beyond that most places are wasting a valuable resource by burning it. a poor historical practice that people do out of habit and tradition than actually understanding what they are doing. this is why after years of such practices their soils are destroyed and they are farming subsoils.

look at any culture that practices yearly burning of fields and then regular plowing. after 100yrs they've ruined their land/topsoil. if they instead buried their field residues they'd not be quite so bad off (but then it also depends upon what they are doing with what they've harvested and if they return any manures or other organic materials to the fields). there is only a certain amount of carrying capacity any location will have. go beyond that and eventually the topsoil is depleted - burning just means faster depletion.

depending upon how much moisture you have available to work with you can recover topsoil and diversity of the soil community, but that takes time. there are methods you can use to speed things up and help things along but it will still take some time.
 

Ridgerunner

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In Arkansas I burned in my garden because I didn't have any real alternative. I didn't have a good way to let the stuff turn into compost, which can take years with wood. I've had groundhogs and possum set up dens under brush piles, let alone lots of mice and rats. Rats especially. When I pruned my trees I had a huge pile of branches, let alone other sources for the burn pile..

The safest place for me to burn was in the garden in winter. Anywhere else was a fire hazard with all the grass around, either when it is green or dead. In the garden I had a large clear space around it that could not burn. And I always talked to the local fire department to get clearance to burn. Wind was more important than how wet it was, though the danger goes up with dry conditions.

When you burn you do destroy some organic matter in the soil. How much depends on how hot the fire gets. My brush piles got pretty hot but the damage didn't go that deep. And you are bringing in fresh material that adds some nutrients. With my experiences it wasn't that detrimental. But as I said I also added compost.

Slash and burn has been used by various peoples around the world throughout history and is still used today. Brazil gets a special mention, indigenous peoples still practice it. It has been used in so many different places by so many different peoples that it's hard to say anything is "typical" but I'll give one standard method. People would clear an area and let the debris dry out, then burn it. This got rid of the debris, added nutrients, and reduced weed seeds and maybe some pests. They'd farm it until productivity decreased, often within a few years. Five years is a number I see often but I'm sure many used a different rotation. Jungles usually don't have very deep topsoil and if you are in a wet area the constant rain leaches out nutrients or washes away topsoil after the protective covering is removed. So they would move on and do another field, letting that one go fallow. After a period of time, depending on where they were located, the field could be reclaimed from nature and used again. In some areas in as little as 20 years. Other areas, much longer.

A few years back National Geographic had a interesting article about some ancient civilization in what is now Brazil that farmed one specific field for hundreds of years, really unusual in that area. The author projected that they were able to do that because they mixed in a lot of charcoal into the soil. The charcoal traps nutrients and keeps them from leaching out. Keeps them available for the plants. To go that long they'd have had to be constantly adding fertilizer of some sort. The author did not get into that, the may have been heavily into some type of composting. But with all that charcoal you'd think that wood ash would have been part of that.

if you believe in greenhouse gasses contributing to global warming. burning contributes to greenhouse gasses. To me that's the biggest argument against burning and I resisted for a few years. But I could not come up with a reasonable alternative. After a few years with those fruit and nut trees growing and pruning ornamental shrubs the volume got to be too much.
 

ducks4you

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a waste of energy and nutrients... burning sends all that energy into the air when it could be going towards the soil community instead. a certain amount of wood ash and charcoal is ok, but beyond that most places are wasting a valuable resource by burning it. a poor historical practice that people do out of habit and tradition than actually understanding what they are doing. this is why after years of such practices their soils are destroyed and they are farming subsoils.

look at any culture that practices yearly burning of fields and then regular plowing. after 100yrs they've ruined their land/topsoil. if they instead buried their field residues they'd not be quite so bad off (but then it also depends upon what they are doing with what they've harvested and if they return any manures or other organic materials to the fields). there is only a certain amount of carrying capacity any location will have. go beyond that and eventually the topsoil is depleted - burning just means faster depletion.

depending upon how much moisture you have available to work with you can recover topsoil and diversity of the soil community, but that takes time. there are methods you can use to speed things up and help things along but it will still take some time.
I am always concerned about composting weeds and allowing their seeds to grow. Tell me more about ruining soil by burning.
 

flowerbug

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I am always concerned about composting weeds and allowing their seeds to grow. Tell me more about ruining soil by burning.
for seeds i bury them deep enough and they can't grow unless disturbed. deep enough is usually a foot or foot and a half. if i'm particularly worried about something i'll put some cardboard or newspapers over it as an extra barrier.

when burning something it is quickly releasing heat and giving off gases. fried bacteria, fungi and other soil community creatures are lost and the physical properties of the surrounding soil can also be changed (baked clay can be pretty hard). what is left behind is a certain percentage of ash. the ash composition varies based upon materials and temperature of the burn. much of what is contained in the ash is trace minerals from where the material was grown along with carbon that came from the air when the material was grown.

if instead the material was buried a larger percentage of the carbon, energy and nutrients will be retained and used by the soil community and it may take many years for it all to be recycled. there are certain bacteria that will use gases from decomposition as an energy source. increasing soil carbon is sorely needed right now to sequester carbon from the atmosphere.

another loss of nutrients is when the ash itself is blown around or washed away. in places where the ground is repeatedly plowed or left bare ash will not have much to keep it in place. if the land is not flat then things easily flow downhill and then away.

in more arid places any bit of mulch you can grow and use to shade the ground and protect it from the sun and breezes the better. burning materials is like burning money and food along with throwing water away.
 

ducks4you

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AND yet, under my burn pile that I removed last month was lovely garden dirt, which I moved for the base of my potato bed. The top 1/2 is 2019/2020 soiled stall bedding, removed last November, now the poo is broken down and ready to grow stuff. The ashes Will turn into soil if left alone and plants like beets like some ash.
 

Dirtmechanic

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for seeds i bury them deep enough and they can't grow unless disturbed. deep enough is usually a foot or foot and a half. if i'm particularly worried about something i'll put some cardboard or newspapers over it as an extra barrier.

when burning something it is quickly releasing heat and giving off gases. fried bacteria, fungi and other soil community creatures are lost and the physical properties of the surrounding soil can also be changed (baked clay can be pretty hard). what is left behind is a certain percentage of ash. the ash composition varies based upon materials and temperature of the burn. much of what is contained in the ash is trace minerals from where the material was grown along with carbon that came from the air when the material was grown.

if instead the material was buried a larger percentage of the carbon, energy and nutrients will be retained and used by the soil community and it may take many years for it all to be recycled. there are certain bacteria that will use gases from decomposition as an energy source. increasing soil carbon is sorely needed right now to sequester carbon from the atmosphere.

another loss of nutrients is when the ash itself is blown around or washed away. in places where the ground is repeatedly plowed or left bare ash will not have much to keep it in place. if the land is not flat then things easily flow downhill and then away.

in more arid places any bit of mulch you can grow and use to shade the ground and protect it from the sun and breezes the better. burning materials is like burning money and food along with throwing water away.
No, you cannot destroy an element like carbon. This is exactly why the Terra Preta soils in the acid clay of the Amazon became so fertile, the toss pots had as much burned firewood as nitrogen sewage and kitchen scraps.
 

Trish Stretton

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This thread reminded me of something I saw my grandfather do when I was very young.
He filled a hessian sack, filled the outdoors copper up with water and steamed the sack of soil -couple of slats of wood to hold it over the rim.

I'm not too sure but I think this was to sterilize the soil to use as a potting mix.
I cant think of any other reason for him to have done this.

Poor centipedes, I'd just collect them up and pop them back outside, I'm sure they would be much happier there than inside a pot.
 

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