30 Browns:1 Green...

Blutranes

Does a forest have 30 to 1?

This area is mainly eastern hardwoods but there are plantations of pine.

I live surrounded by pine plantations. For a compost bin the ratio is still 30:1...

Blutranes

Blu, thank you
If my question was about a compost bin that would be good information.

30:1 is optimum for Carbon to nitrogen, but your green items have a lot of carbon in them. Most of the stuff that we put into the compost is not pure carbon or pure nitrogen but a combination. Items considered green are higher in nitrogen than brown items, but they still have a lot of carbon in them.

And even if the ratio is incorrect, the stuff will still decompose, it just may take longer or smell bad, but it will still turn into compost anyway.

More than than thinking about the ratio; I go by what the pile is doing. If the pile seems slow or inactive, it could use some greens. If it seems wet or stinky or full of flies, it needs browns. But I am just a pile it up and let it rot kind of composter. I don't do a lot of mixing or measuring of temperatures.

A lazy composter...

Its more like 1:1 browns to greens. Browns contain less than 1/30th nitrogen and greens contain more than a 1/30th. By mixing them you achieve a balance that composts well. Too many greens means too much nitrogen, the microbes have an orgy, use up all the air, give off ammonia and worse, and the whole thing gets stinky. Too many browns and the bacteria that would heat up the pile don't have enough to eat, the pile stays cold, and you have to wait years for fungi to munch through all the browns.

The greens you add will also have some Carbon and any browns you add will also have some Nitrogen, so the ratio of greens to browns need not be 30:1. It depends on what you are adding. An easier way to do this is 3 parts browns to 1 part greens or 3 parts of a high Carbon source (leaves) to 1 part of a high Nitrogen source (manure, green vegetable waste, etc.). There are numerous charts the list various materials C:N ratios and the link below is one.

Here is a link that might be useful: C:N ratio chart

What is confusing about the 30:1 guideline is that is refers to 30 parts carbon to one part nitrogen by weight, not volume. Who weighs this stuff, and figures out the percentages? In practice, my experience has been about equal volumes of browns and greens, or the 1:1 suggested by shrubs and bulbs, works fine, and by that I mean four to six inches of browns and then four to six inches of greens in each layer. Kimmsr says 3:1, which might be better, but her ingredients seem to be higher in N than mine. I guess it all depends on what you are using as browns and greens, since different ingredients have different percentages of C and N. My 1:1 is straw and leaves for browns, and fresh green garden wastes and a sprinkling of blood meal for greens, when I don't have enough green plant matter. Maybe I've got it wrong, but that's what I've been doing with good results.

Keep in mind that if you get the ratio completely wronge Keep in mind that if you get the ratio completely wrong you will still get compost. It might take more or less time, but one way or another it is going to break down. The 30:1 guideline is aimed at getting the compost to a reasonable temperature and making compost in a reasonable amount of time. And as others said above it does not mean 30 parts Âbrown to 1 part Âgreen. I have never really liked the Âbrown Âgreen thing much. Leaves for example are usually between 40:1 and 80:1 while sawdust is generally around 400:1. Both are Âbrowns but certainly are not equivalent.

Ideal C:N ratio of 30:1 means the green(nitrogen rich) and brown (carbon rich) ingredients average 30:1.

Let's take a example that could be created in the winte; leaves and coffee grounds (Starbucks bags).

Some ingedients are simple, i.e. coffee grounds = 20:1
A mix of leaves, lets say 40:1. (They range from 20:1 to 80:1)

So a mix of 1:1 by weight would be aprox. 30:1, your ideal mixture. The leaves are measured dry, so a little water would have to be added. I can get this mix up to 140F or so in the summer. When I used grass and leaves; no water has to be added at first.

In a few days the core temp rises sharply, and I would turn the pile and add water to the grayer material. If I had kitchen scraps, they would be added at this time.

A compost theromoter at least 18" long is a necessity, if you want to run hot piles. I like hot piles because smelly ingredients like fish parts can be added to the core, and more compost can be made during the year.

The Cornell Composting site has many figures to get an idea of ratios from, but just the few mentioned should be enough to get you started.

Yoicks! I had no idea sawdust was so high in carbon. I only use it when I run out of stockpiled leaves usually around August. Sounds like a little bit goes a long way.

No, the 30:1 ratio has nothing to do with "greens" and "browns" ratio, except in a very general way. 30:1 is the ratio of Carbon to Nitrogen, the C:N ratio. The terms "greens" and "browns" are easy to remember acronyms for Nitrogen and Carbon because generally greens are high nitrogen and browns are high carbon. But there are exceptions to that rule of thumb, ie. manure is brown and high in nitrogen.
Putting down 3 parts of browns to 1 part greens is an easy way to put your pile together and comes directly from Sir Albert Howards original recipe for compost of 6 inches of vegetable waste and 2 inches of manure, although he did want 1/8 inch of soil on each layer to innoculate that with the microbes that would digest it which today we know is not necessary because with better reseach equipment we can see things he could not.

30:1 is not browns to greens, it's carbon: nitrogen.

many well intentioned people will tell you that it's really important, or even critical.

You know what will happen if it's 20:1, or 40:1? It will produce wonderful compost. If it smells, check the moisture. If it's not too wet- add browns. If it's not composting fast enough for your liking, and it's a new pile- add greens and check moisture.

Either that or start a spreadsheet of everything that you add, the mass added, and calculate the C:N ration. Tell me how that works out for you :)

"although he did want 1/8 inch of soil on each layer to inoculate that with the microbes that would digest it which today we know is not necessary because with better research equipment we can see things he could not."

That is not what Sir Albert said about soil. The entire Indore compost technique can be found at the link below. The ratio is not critical, however the soil spoken of could make a world of difference in compost making. Scroll down to the heading:

"Soil and Urine Earth"

There you will find the exact wording and the reason why the soil is so important. If one is fortunate to be able to get their hands on urine earth your pile will be in for a treat. I have used urine earth for a number of years now and do not make a pile without it. I have an agreement with one of my neighbors to get soil from his stalls; I just have to replace what I take. Adding urine earth to a lasagna bed can make a world of difference too, if you can get enough, but even a thin layer will add nitrogen to the bed. Although we all know compost can be made without urine earth due to our modern living, to say it is not needed could be better stated as "if you can get it, do it".

From the site:
"Without soil, "an even and vigorous mycelia growth is never quickly obtained." Howard said, "the fungi are the storm troops of the composting process, and must be furnished with all the armament they need."

With all the talk about the importance of micorrhizae, paying for inoculants, and Glomalin Sir Albert was more on the money than all these fancy highly technical machines seem to be able to match. Even the Rodale Institute is re-discovering what Sir Albert has already given to us. The more thing changeÂ

Blutranes

Here is a link that might be useful: Making Superior Compost