How much char by volume?

Im making more horticultural char for the gardens and thanks to our logging on the land we have a surplus of small stuff to burn to turn into horticultural char for the soil.

How much char are folks using by volume?







I dont know this guy but he shows what 12 quarts of char looks like after adding it to a cubic foot of soil.

I usually put my spade/shovel into the earth, in a ring at the drip line around my trees or bushes.  I move the shovel back and forth to make a crevasse on the line around the tree.  Then I fill the crevasse with  my crushed, inoculated biochar.  I am gradually trying to make sure that there is a line of biochar, every 3-5 feet throughout my suburban yard.

John S
PDX OR

I've been doing a couple batches a year in a big multi-purpose pit. We have had a bunch of pine trees knocked over in storms and falling branches accumulate all year. I use the logs for hugelkultur, garden beds, or other projects, but the branches eventually build up to a certain point and when there is time and the weather is right I get the hose out and make a batch.  

So far each time I get 3-4 wheelbarrows full. Over the last few years I've done maybe 5 or 6 batches, and spread most of it to around 3000 sq ft. of garden space. I'll add most of the batch to a compost pile, and spread it from there. It seems to be making a difference, although I can't say to what extent. Our soil seems to be improving steadily in texture, moisture holding, and plants seem to respond well to the compost.  

One great thing about this forum is that so many people have different styles of using biochar that they can do with their property.  You will almost surely share ideas with somebody whose situation is similar to yours.  I live in the suburbs, so I couldn't do a trench burn but many people here do use that technique.  I built an oven for biochar out of a 55 gallon drum and I put it  in the driveway, because that's all I can do. I don't have acreage.

John S
PDX OR

I really like calling it "horticultural char." That's just such an engaging pathway into the mainstream. Naming matters!

How much to use? Phew, good question, and I'm not sure there's a definitive answer. I'm in a sand/silt pit, so I'll take all the raw bio material I can get. Still, I find that char is only one component when building soil. It seems to work best when fermented with all sorts of crazy/stinky compostable stuff. Not definitive science, only my shovel in the ground.

I have read in various places that it really helps a lot until it's about 15-20% of the soil. It doesn't really hurt after that, but it doesn't help as much. I've also read that you don't want it exposed to sun so it dries out. Better to have it covered with soil, compost,  mulch, etc, so it doesn't dry out. Then it isn't great housing for microbes.
John S
PDX OR

Outside of a container adding a percentage of char by soil volume would be too much of a hassle for me.
I'm leaning towards vertical mulching as a way to use biochar in the landscape.

I don't think I will be making biochar forever.  I'm 60 now, and it is somewhat challenging to lift full buckets of inoculated biochar to drain them when I'm drenching them.  I figure I probably won't be able to do this when I'm 75.  I figure I'll probably be done in a year or two.
John S
PDX OR

John Suavecito wrote:I don't think I will be making biochar forever.  I'm 60 now, and it is somewhat challenging to lift full buckets of inoculated biochar to drain them when I'm drenching them.  I figure I probably won't be able to do this when I'm 75.  I figure I'll probably be done in a year or two.

That's unfortunate. And yet -- I think there are many creative ways to rework a system to essentially eliminate the heavy lifting. Don't give up yet!

You're right. I may figure out another way to do it.  Or I may volunteer to teach other younger, stronger people how to do it.  I have a suburban yard, so I won't need to continually make biochar for it until I'm 85. After a certain concentration, one's efforts are best placed elsewhere.   I don't want to move ever. Or, as I say, you can move me out of here in a pine box.  So, yeah, there may be other opportunities that don't involve lifting 50 pounds regularly in order to make something that I already have enough of.

John S
PDX OR

It's true, your yard may reach optimal carbon levels.

But the rest of the world needs it desperately. Community gardens, backyard growers, backyard chicken coops. I like your idea of a community or volunteer team approach -- making char for the greater good.