How many cubic yards is your bin?

I had a lot of difficulty getting a straw/grass mixture to sustain prolonged heat as well. I suspected that it was the straw. Later I was given a link that contined this little nugget:

"Woody materials, and especially straw, have a high percentage of carbon, but much of it is locked up in complex molecules that only become available over time; too late to be of use with the immediately available nitrogen." (my bold)

Lloyd

It is not the bin that makes "hot" compost it is the C:N ratio and if your mix was 3/4 manure and only 1/4 vegetative waste that was the problem. You need, roughly, 3 parts vegetative waste to 1 part manure and then the bacteria at work need just enough, and not too much, moisture and air. Too much moisture, water displaces air, can slow the bacteria down just as too little can. Volume also aids the bacteria in getting to work.

Thank you guys for your help!

Jeremy, The bin is a 50 gallon barrell set on its side and placed in a frame with rollers. I would estimate that it is 1/3rd of a yard.

Kim, I was afraid that the ratio was the problem. I'll take about half of the current mixture out and replace it with carbon and see what happens. Thanks!!

I don't see how replacing greens with browns is going to make it hotter. How fresh is the manure? Is what you're calling manure mixed with straw or other bedding, or do you mean pure poop?

kimmsr is right, the mix is important, but so is air, moisture and pile size. They each play a critical role. Your 55 gal drum is about 7.3 cubic feet, or just over 1/4 of a cubic yard. Not that this can't heat up, but it's generally recommended to have a cubic yard sized pile to get real heat and keep it in. At least half a yard in my experience.

Finally, what's the ambient temperature? In Zone 8 I guess you're pretty warm.

Hi Tox,

My understanding is that replacing the nitrogen based portion of the compost - the manure (just manure - fairly fresh but dry) with more carbon based materials is necessary because I have to high of a nitrogen mixture.

I know that I can get temperatures up to 125 with this particular barrel because I have done so before. This time I apparently didn't have quite the right mixture. I'll make the change to night after work and report back.

A couple very basic compost rules of thumb:

If its not as hot as you'd like it to be; add more greens.

If it stinks; add more browns.

Joe, that confused me. Is manure considered a brown or a green? 3/4 of my mixture is manure and its not any where near as hot as it needs to be (50 degrees F this morning). Kim is telling me to add more carbon (I read that to mean brown stuff) and it sounds as if you're telling me to add more green stuff because my pile is not hot enough. I'm confused.

Mrlupin,
When Kimmsr said "It is not the bin that makes "hot" compost it is the C:N ratio"

She was being over simplistic to make her point...

She knows that if you have 1 quart of all the right ratio's it will never get hot,there is not enough material, what some of the other posters are saying is correct,1 sq. Yard is the smallest (some also say the "RIGHT" size) for a hot compost pile ,with all the right ratio's...

Hi Jon,

I think I understand what Kim was saying about the C:N ratio. The manure is a nitrogen based substance and I have too much of it. I'm fairly certain I have sufficient critical mass to achieve high temperatures - my brother made the exact same composter and has had great success getting high temps and fast compost. I, apparently, have just been having trouble with the mixture. Thanks!

Kevin

It is unlikely that you would have too high of an N component using horse manure, it's not that strong of an N. Cornell lists it with a range of 22-50:1 and an average of 30:1.

Lloyd

I've never had a drop of 35F in my core temp in one day. I suggest you either:

1. are not hitting the hottest core when measuring
2. compost therm. is stuck or not reading correctly

Keep in mind that the core temp is often NOT at the very center of the pile. If your pile is resting on soil or concrete, the highest core temp is usually below the very center of the pile. This is because the mass below the compost pile stores heat also.

The usual problem is often a less than optimal ratio of green/browns, or too large particle size. The comment that the pile had been turned once leads me to speculate that a lack of water and air slowed things down.

jonhughes your sexism is showing. I have never been a she.
The range of Nitrogen to Carbon listed for manures is because what was tested was fresh and aged manure, so fresh manure would have a C:N ratio closer to 22:1 and aged manure would be closer to the 50:1 although even at that the ratio is not that far off the optimal 30:1. That might also reflect the amount of bedding that was in the manure.

Good grief, how the heck would you know that the range "is because what was tested was fresh and aged manure"? I call bovine scatology on that one.

It is not the ratio!

50 gallon drum is just over 6 cubic feet (source: google), using a compost calculator, inserting a 4 cubic foot volume of horsey dung with a 2 cubic foot straw (pretty close to the 3/4 to 1/4 numbers given by OP) we get a 28:1 ratio. Now jive the numbers around a bit and unless one goes nutso, the ratio won't go that far from the 'optimum'.

It may be moisture, it may be volume, I doubt it's not enough air (tumbler), it may also be the C in straw is not easily enough available for thermophyllic micros to flourish to a sufficient degree to get sustained heat, but it's not C:N ratio. I'll bet a cup of coffee on that.

Lloyd

..

Seems to me Kimmsr has a point. You gotta get the mix right.

Can't ignore Lloyd though. A smaller volume makes everything harder vis-a-vis hot composting. In a smaller volume the mix is going to be more critical.

I just assembled a bin for the first time without grass clippings. Just leaves and chipped sticks. 17 cu ft. Got 150 F for a very short while then 140 F for a day or so and then 130 F for another couple of days then into the 120s. Turned if after week adding grass clippings. Got a couple of days of 140 F and 130 F for the rest of the week. Just turned it again tonight in the rain. We'll see.

I would expect the given mixture in a 1 cu yd to do something similar. I think the small size just hindered things some.

I haven't worked with straw but something tells me it's made to be rot resistant. That tells me it will compost slowly. Couple Lloyd's experience with an observation supporting our fears plus the small volume and I think things are just going to go slower.

Not a major disaster. It'll rot. Just not as fast nor as hot.

to sense

..

mrlupin, thank you for giving us so much information. You have obviously read a thread or 3 here. ;-)

About your compost not heating, listen to joepyeweed.

kimmsr wrote:
>>jonhughes your sexism is showing. I have never been a she.

No offense, but I assumed you were too. Probably a result of having 'kim' in your username. You could be an Asian male, though, or kimmsr has nothing to do with your name. If the former I would be guilty of Eurocentrism or some such, rather than sexism. :-]

As long as we are off thread could some one tell me why we need user names on a garden forum?? When I signed on It would not except my real name. It makes me feel like I am lying just to post on here! As for kimm-sr sr= old man~~ So I think Kim old man LOL.

Curt~~~~~= Curtis Drexler, Old Man. I'm on Face Book under my real name. You are welcome>>>>>.

Sorry: That's accept not except my real name.

Curt :-/

Using handles instead of real names is a generally accepted practice for security purposes. So some wacko with a compost vendetta doesn't track you down with pitchfork in hand! Although I agree with you, one should be able to use their real name if they so choose.