Composting sawdust question

gregory · March 14, 2015

A few months back I was looking for a closer source for horse manure.
I thought about the sheriff and police stables which they share. I was told to bring my trailer and they have a front end loader. So when I got there and they started loading it I realized it was a great deal of sawdust and not shavings.

My yard isn't large and I picked it up in the furthest back corner. I noticed it was maybe 15-20% manure. So I found a local stable that has a lot of horses and I scoop up fresh manure in the fields. This was back in December and it heated up to around 130-135 plus it was cold. It didn't stay that hot for long, and each time I tried to add coffee grinds and other kitchen wastes the balls of manure fall out. I added a great deal hoping it would start cooking and speeding up the composting.

I was at a feed and seed store and I was asking how long they think it will take for it to compost to where I can use it in my garden. They didn't know, but they suggested adding lime to help it in breaking down.

Has anyone tried this?
Btw I have done a lot of research on the net & there is a lot of bad advice and some good. I don't think I want to add ammonium nitrate although when the grass starts growing definitely add that.

Redbaron · March 14, 2015

Actual saw dust as opposed to wood chips has a VERY high carbon to nitrogen ratio and is VERY hard to break down. I have seen ratios as high as 300-400-500:1 or higher! (depends on the tree used) You may find that urine is needed. Lots of it. But if you don't want to go that route, remember to compost hot you need around 30-40:1 or less, 25:1 would be ideal.

So for example lets say you want to heat up the sawdust with a manure that has a 15:1 carbon to nitrogen ratio. If you mix it 50/50 with manure that would be 415:2 or 207:1. Still way too little nitrogen. So you would need at least 20 times more fresh manure than sawdust or 700:21 or ~35:1

That's of course to do fast hot composting. Slow composting works a bit differently.There are things that fix nitrogen from the air like methanotrophs that feed on the methane produced by decay and have nitrogen as a waste product that will eventually rot that sawdust. But it takes much longer, sometimes years.

Worth1 · March 14, 2015

Might sound crazy but add stump remover to it.
It is potassium nitrate.
The same stuff you cure meat with and make black powder out of.

Without nitrogen or mushrooms it will take forever to break down.

Worth

Tracydr · March 14, 2015

I would think tha urine from stall cleanings would be enough. I have been adding lime and a bit of organic fertilizer to the shavings I'm composting from my horse trailer. It's been about 8 months and is nearly finished. I have it in a tumbler and added lots of kitchen scraps,too.

Redbaron · March 15, 2015

Quote:

Originally Posted by Tracydr

I would think tha urine from stall cleanings would be enough. I have been adding lime and a bit of organic fertilizer to the shavings I'm composting from my horse trailer. It's been about 8 months and is nearly finished. I have it in a tumbler and added lots of kitchen scraps,too.

It is usually enough for slow compost.

What I wrote above is for fast (hot) compost. The kind that reaches 160 degrees and is finished in 28 days.

beeman · March 15, 2015

Why not use it as a 'brown' source? I usually add it to my grass clippings and it really gets that stuff steaming really quick.

4season · March 15, 2015

When I was a kid, my sister had a horse and used wood shavings for bedding. The cleanings were about 1/2 shavings and piled about a foot and 1/2 deep back of the garden. A couple of years we were amazed at the great soil where the stuff had been piled. It may take a year or two but should make great compost.

gregory · March 15, 2015

I figure it might be best to toss as much excess as I can today. I am going to try to sift out the manure and get rid of the sawdust if I can. I really don't want to add nitrates.
I like thin shavings from the stalls those seem to break down much quicker.

March 14, 2015	#1
gregory Tomatovillian™ Join Date: Jan 2015 Location: mobile zone 8 Posts: 83	Composting sawdust question A few months back I was looking for a closer source for horse manure. I thought about the sheriff and police stables which they share. I was told to bring my trailer and they have a front end loader. So when I got there and they started loading it I realized it was a great deal of sawdust and not shavings. My yard isn't large and I picked it up in the furthest back corner. I noticed it was maybe 15-20% manure. So I found a local stable that has a lot of horses and I scoop up fresh manure in the fields. This was back in December and it heated up to around 130-135 plus it was cold. It didn't stay that hot for long, and each time I tried to add coffee grinds and other kitchen wastes the balls of manure fall out. I added a great deal hoping it would start cooking and speeding up the composting. I was at a feed and seed store and I was asking how long they think it will take for it to compost to where I can use it in my garden. They didn't know, but they suggested adding lime to help it in breaking down. Has anyone tried this? Btw I have done a lot of research on the net & there is a lot of bad advice and some good. I don't think I want to add ammonium nitrate although when the grass starts growing definitely add that. __________________ Zone 8 Mobile AL

March 14, 2015	#2
Redbaron Tomatovillian™ Join Date: Sep 2012 Location: Oklahoma Posts: 4,488	Actual saw dust as opposed to wood chips has a VERY high carbon to nitrogen ratio and is VERY hard to break down. I have seen ratios as high as 300-400-500:1 or higher! (depends on the tree used) You may find that urine is needed. Lots of it. But if you don't want to go that route, remember to compost hot you need around 30-40:1 or less, 25:1 would be ideal. So for example lets say you want to heat up the sawdust with a manure that has a 15:1 carbon to nitrogen ratio. If you mix it 50/50 with manure that would be 415:2 or 207:1. Still way too little nitrogen. So you would need at least 20 times more fresh manure than sawdust or 700:21 or ~35:1 That's of course to do fast hot composting. Slow composting works a bit differently.There are things that fix nitrogen from the air like methanotrophs that feed on the methane produced by decay and have nitrogen as a waste product that will eventually rot that sawdust. But it takes much longer, sometimes years. __________________ Scott AKA The Redbaron "Permaculture is a philosophy of working with, rather than against nature; of protracted & thoughtful observation rather than protracted & thoughtless labour; & of looking at plants & animals in all their functions, rather than treating any area as a single-product system." Bill Mollison co-founder of permaculture Last edited by Redbaron; March 14, 2015 at 07:50 PM.

March 15, 2015	#8
gregory Tomatovillian™ Join Date: Jan 2015 Location: mobile zone 8 Posts: 83	I figure it might be best to toss as much excess as I can today. I am going to try to sift out the manure and get rid of the sawdust if I can. I really don't want to add nitrates. I like thin shavings from the stalls those seem to break down much quicker. __________________ Zone 8 Mobile AL

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March 14, 2015	#3
Worth1 Tomatovillian™ Join Date: Feb 2006 Location: Den of Drunken Fools Posts: 38,539	Might sound crazy but add stump remover to it. It is potassium nitrate. The same stuff you cure meat with and make black powder out of. Without nitrogen or mushrooms it will take forever to break down. Worth

March 14, 2015	#4
Tracydr Tomatovillian™ Join Date: May 2011 Location: Laurinburg, North Carolina, zone 7 Posts: 3,207	I would think tha urine from stall cleanings would be enough. I have been adding lime and a bit of organic fertilizer to the shavings I'm composting from my horse trailer. It's been about 8 months and is nearly finished. I have it in a tumbler and added lots of kitchen scraps,too.

March 15, 2015	#6
beeman Tomatovillian™ Join Date: Jul 2009 Location: Ontario, Canada Posts: 692	Why not use it as a 'brown' source? I usually add it to my grass clippings and it really gets that stuff steaming really quick.

March 15, 2015	#7
4season Tomatovillian™ Join Date: Aug 2014 Location: albuquerque Posts: 308	When I was a kid, my sister had a horse and used wood shavings for bedding. The cleanings were about 1/2 shavings and piled about a foot and 1/2 deep back of the garden. A couple of years we were amazed at the great soil where the stuff had been piled. It may take a year or two but should make great compost.