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Rookie Question: Green/Brown Ratio?  RSS feed

 
Chris Watson
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Location: North of Detroit (5b to 6a)
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I have read a lot about composting, and every source comes up with a different carbon (brown) to nitrogen (green) ratio for optimal compost. They're not even kinda close ratios, either. I've seen anything from 3:1 nitrogen-heavy all the way to 30:1 carbon-heavy. A don't know whom to believe out there in the blogosphere, so I figured I'd come in here and consult people who do this for real. Any thoughts?
 
S Bengi
Posts: 1357
Location: Massachusetts, Zone:6/7, AHS:4, Rainfall:48in even distribution
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Finish compost/humus has a C:N ratio of 30:1(or close to)
Winter rye has a 90:1, while beans might be 10:1.

However if we are just making compost i would do a 1:1 up to maybe 3:1
 
David Hartley
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The ideal ratio to maintain when putting together a compost pile is a carbon to nitrogen ratio of 25~30:1... Kitchen scraps average about 20:1, chicken manure is around 8:1, as mentioned straw is around 80~120:1

Locating a carbon to nitrogen ratio list will greatly aid in the formulating of your pile
 
Saybian Morgan
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Location: Lower Mainland British Columbia Canada Zone 8a/ Manchester Jamaica
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don't have a ratio science panic over living systems, if your in the 1/3rd manure 2/3rds carbon vicinity your method of composting while mainly dictate at what stage do you amend from there. An 18 day active aerobic compost is going to have allot of different key moments where you can adjust things as there going and your observing. In that style of process your going to be directly interacting with the biological process through it's phases and stages, It's such a real time engagement you can watch a bone go from fresh to bone meal. The longer methods ameliorate themselves over vaster expanses of time, what was once too acid has finally broken down enough eggshell to go neutral for instance.

Once you read a few charts on common material ratios you can start to extrapolate there characteristics onto other things that are not on the list. I've never been able to find a calculate that could do the math on how much pee to how much woodchips, but I do know the grand variable is surface area over any other quantity factors. So whether or not to shred can take an unknown or out of balance ratio and put it back into a biologically available range.

I've stressed my brains out over so many things in the beginning that it just turned to procrastinating, but good honest information based on experience over authoritativeness seems to really put the shovel to the duck pen.
You can absolutely make veganic compost without meat or manure, but again you now got a heap of alfalfa ton your hands to do battle with 2 bales of hay and you've got to shred it down with a force to make it available.
 
Chris Watson
Posts: 85
Location: North of Detroit (5b to 6a)
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Are these ratios by weight or by volume? And if by weight, wouldn't green wastes have a lot of water weight to factor in?
 
Ken Peavey
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Location: FL
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The target is 25-30:1 by weight
For the greens it will include the moisture. As the greens dry out, they lose N and become browns.

You can produce compost qualitatively rather than quantitatively.
If it smells, you have too much N, add browns, give it a toss.
If its not warming, not enough greens, add more, give it a toss.
If it is cooling down and the browns are recognizable, add greens, give it a toss.
More bugs than normal, give it a toss, if the bugs persist, too much N, add browns, give it a toss.

Compost is easy. You can put in all the effort you wish, or ignore it do it's thing. If the mix is far from optimal, it will still compost. If it dries out, it will compost slowly. If you never toss it, it will still compost, although the outsides will go slowly. Some will tell you not to put meat and dairy in the heap. You can, it will compost, but an odor may develop. I'm out in the woods, it matters not what it smells like. Odors, however, can attract critters, which can be an issue in a more densely populated area.

Lots of people swear by hot composting. The high temperatures kill off pathogens and weed seeds. Ain't nothing wrong with a good hot steaming pile. If you get this, you are doing just fine. Some will say you can get usable compost in just a couple of weeks. On this aspect I am not in full agreement. In order to achieve a stable hummus, the stuff needs to cure for a few weeks at least, in my opinion.

Slow composting has advantages, the most notable is that it requires very little attention. I've made so much compost that I dont really bother with it. I've got several heaps around here at any given time. The chickens turn it for me. Slow, cool piles take considerably longer. If space is limited, it may suit your needs to get it moving faster. These piles also will not destroy pathogens as effectively. Weed seeds, on the other hand, will either compost or sprout, in which case the chickens will make quick work of them.

There are all sorts of recommendations for containers. There are store bought spinning drums, wire cages, pallet bins, pits, and heaps on the ground. If you find a containment method that suits you fancy, by all means, go for it. For my needs, a heap here, a heap there works just fine. I'm not worried about space or appearances.

If you are new to composting, I'd advise you to not get hung up on exacting recipes, following the rules, or understanding the science. Just get started. Gather materials, pile it up, get it wet. Problems are usually not so bad that you will lose sleep or PO the neighbors. A bit of tweaking will set things right pretty quick. If you live in town, then yes, leave out the meat and dairy for now until you have a better understanding of the process.

If you have specific questions or problems, ask in the forums, and don't be afraid to send me a Private Message. Composting is one of my favorite things.
 
2017 Permaculture Design Course at Wheaton Labs
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