The minimum size compost pile I have seen on most all the web sites I look at is 3 x 3 x 3, mine currently are 4 x 4 x 4 although I have had compost piles that were 6 x 6 x 45. How much material do you normally have readily available? That would determine the ultimate size of your compost pile.

In my opinion there is no minimum or maximum size to a compost pile or bin. I have a friend who has a very small yard and she just makes a little pile at one end of her garden in the fall.

You can use a trash can if that's what you want to do. Just be sure to add lots of holes. I have a couple of 32 gal. trash cans that I have put holes in, mostly to store leaves for the fall. A couple of times, if the leaves got mixed with some grass clippings, by the next spring it was compost towards the bottom.

Val

Would a trashcan be big enough to create enough heat to properly compost horse manure?

You are talking about just one ingredient - horse manure - so yes, you can age it in any size you want and a container isn't required at all much less an expensive one.

But please understand that aging manure is not the same thing as "composting" in the usual sense and that is what is causing your confusion.

Composting requires multiple ingredients - some in larger amounts and differing sizes - and some activity on the part of the gardener. So that is one reason for the minimal size requirements - and 3x3x3 is the standard minimum to get activity going in the pile. Bigger is usually better and faster but not required if you are patient.

Dave

I've got a bin that is much smaller than the "minimum" and I've managed to get hot compost on many occasions.

Lois,

ALL organic matter will decompose, eventually.
I make good compost from ONLY horse manure +water+air.
And good compost ONLY from grass clippings +water+air.
The ONLY major difference between 'aging' and 'composting' is management air and water in the mixture.
But I do make even 'better' compost faster, from combining both manure and grass +water+air.
Heat-generating microbes will 'quicken the pace' by heating the toughest materials, but are NOT essential to produce quality compost.

Composting is simply a 'management' activity to help speed up Mother Nature's process.
I am an "intensive" management composter - because my focus is to obtain the very best quality result in the shortest period of time.
I'm happy when I start-to-finish a 5' x 7' x 4' high pile in 90-120 days. Almost a ton, dry weight.
But most folks don't consider that as 'fun'.
Figure out what would be an enjoyable, do-able level of activity, to produce the amount of product YOU want, how fast. Ingredients/tools/effort/time...Same as cooking.

The methods of management are as varied as there are people, who want material for plants, in which nutrients are already 'decomposed' back into a form that plants can uptake again quickly.

Trash can or barrel will work. Bottom and side 1/2" dia. holes spaced 8" - 10" apart worked best for me - holes too large and material comes out too much. But keeping the lid on tight during rolling is IMPORTANT.
For a metal trash can, pre-drill for 6-8 screws around the top edge. Tie an old sock to each handle for lifting, then U-bolt the handles down tight. Screws won't keep the handles tight and are dangerous when reaching into the can.

Put in the top screws, lay it down and roll it around. 3-5 minutes every 3-4 days. Add water if needed AFTER it has been aerated.
If the material becomes too wet, it won't mix/aerate well (ka-thump; ka-thump). If that happens, add dry leaves/grass and keep rolling. Might be difficult to set upright again, and rolling it back up an incline, can get tiresome. Lots cheaper than a tumbler, though.
Get a 2nd can working - stop putting scraps in #1 after 2 months, while you fill up #2 for 2 months.
After a total of 4 months, put the #1 material on/in the garden dirt and start a new 'pile' in it.

After that, you have a continuous supply every 2 months. Quality of what you get depends on what/how much you put in and how you managed the process.
If you have more available materials, and/or need more 'finished' product than 2 cans makes in 4 months, think about starting a pile.

People only move material. Mother Nature composts.
By using microorganisms. Composting is 'ranching' in a microsopic sense. Some microbes create heat - others don't, and most thrive in lower heat ranges created by the ones that do, if they do. Microbes have their own 'cycles' based on what's in the material, that they can 'eat'.

Microbes 'breathe' oxygen and 'exhale' carbon dioxide.
Different from the way we do - but same result.
If you tie a bag over a critter's head, the CO2 that it exhales, will quickly kill it - by replacing oxygen.
Does the same thing to microbes when the air trapped in decomposing material becomes toxic due to CO2 accumulation.
Turn the pile before too many of the 'critters' die, and you won't have to kick-start the pile 'over' again.

Tumbler-type 'bins' do aerate material well - but have relatively small capacity, same as trash can. The larger ones work better, to the degree they contain more biomass.

No structure is necessary to contain material being composted, but where material is thickest - decomposition is fastest (biomass compression) - and further toward the edges of a conical pile, decomposition takes place at a slower rate.

Higher, vertical pile walls compost more completely, faster - especially with compressed outer edges to retain moisture.
I obtain vertical pile walls without a stationary bin, using a simple, adjustable wood frame.

Small-sized materials decompose faster than larger-size pieces.
How much material you obtain to compost with, how much space you have available and how much energy/time you have to apply to composting, essentially determines size and convenience issues of operational design.

For 'fast' composting, the 'standard' is one cubic yard, with the 3' high being more important than width and length dimensions, but as Val commented - a little conical pile will work - just takes longer.

If you opt to use a wire screen as a 'bin', I recommend tamping the sides snugly to 'insulate' the pile and help retain moisture. Dry material does not decompose quickly, even if piled 10' high.

Air flow into a pile is also not a major issue, and with coarse material, can be detrimental by drying it. Simply turn the pile before the microbes run out of air, and make sure plenty of gas exchange takes place in the material when you turn it (screening).

If pile air supply does become depleted - then anaerobic microbes take over later - which are slower - and a bit smellier - but will do the same job eventually (as long as moisture is sufficient). Plan to turn the pile before and after taking a long vacation.

Use materials at hand or easily obtainable.
Don't spend money on composting - unless needed to make you happy - in the doing of it - and with the results.

Remember the primary principle of composting:
With YOUR pile, YOU are the ONLY expert.
And some of the advice you get will be very wrong.
Simply because 'THEY' don't know what YOU are doing.
When you make soup - you make it your way - to your taste - and that makes it the RIGHT way. It's your soup.
Some people follow 'recipes' - some don't.
Depends on the degree of consistency desired.

Important thing is enjoy the activity.
Keep telling yourself: "...it's good for me...it's good for me...as your friends walk past (whispering to each other) as you roll the trash can round 'n round...

Robert

The type bin may be chosen by the ingredients types and amounts, and the patience (or lack of same) of the compost person. My first bin was a plastic thing that costs $65. My second was a tumbler at $350. Neither bin is used any longer. I found that a mesh bin at $15 worked great. Cheap, bigger, easy to turn. Better for smelly items like rotting fish too. But it took time to come to this conclusion. The first time composter will see product advertising before they read about DIY bins on GW.

I have eight mesh bins. Some are 4-5' in diameter and 24" high. Others are 4'by8'by18"high. I shred leaves in the fall and spring is a favorite season to start hot piles. Grass is available in addition to used coffee grounds.

Wow, I came to the right place... Composting is an art form here, LOL.

The horse manure I have is stall bedding material from the stable down the road. I was hoping to mix it with some dead leaves and create some good garden soil for my roses.

Lois in PA

I made my bins from recycled dog runs, you can add onto the bins as needed. If you are like most composters, after you see the benefits of compost, you will be adding on. Do not worry about not having enough material on your property. You can get all sorts of material for free and some delivered free. Here is a link to my fall composting with photos taken about 2 mo ago. http://www.jbest123.thegardenjournals.org/?p=80

John

Just a warning. Robert mentioned above grass clippings+air+water - very stinky pile if it's all green, the browns(carbons) are what will prevent any size pile from smelling bad.

My first pile less than 1 yard, about 2.5x2.5 round w/ chicken wire. It was over 3 ft tall to begin and shrunk rapidly. I had finished compost in less than 90 days. It's been turned a few times since to remove bigger pieces of cardboard that I put in the current cooker, the new one is over 4ft tall and about 3ft around still a chicken wire circle.

It usually starts with one trash can. Its only one small can what can it hurt. You fill the can with a few kitchen scraps, some shredded junk mail, it heats up pretty fast, yields some nice black gold. That sense of satisfaction of turning what was once garbage into an invaluable soil amendment gives you a sense of pride and satisfaction, that rolls over you like a warm blanket. Pride is one of the seven deadly sins you know.

Then you realize that you have a lot more garbage that could be easily composted, so you use more of your kitchen scraps, and more of your junk mail, then you start adding dryer lint, vacuum cleaner bags, and coffee filters. You find yourself cooking more meals to generate more kitchen waste. So you make even more compost and reduce even more of your garbage.

In time, you may find yourself needing a larger bin to make more compost. Then you find yourself stealing garbage, kitchen scraps, and manure; from friends, families, neighbors, and even complete strangers to get that organic matter fix.

Sure go ahead and start with a trash can. I have one right here that you can try for free. The first one's free...

JPW - so funny and SO true! I was smiling all the way through. There's only one small part I disagree with:

You find yourself cooking more meals to generate more kitchen waste.

I'm getting at the age where cooking is a bore so the above statement doesn't reflect our household but here's one that does.

About once a week we used to have a left-over night. I pulled out everything that was left over and had the family go at it. Everyone picking certain things and then heating them up in the microwave. I find us doing that less and less. Now I don't stress too much about the left overs anymore 'cause I know I can pitch 'em in the compost.

Val

So you use to have left over night... and now you pitch them in the compost instead of eating them... kind of proves my point, doesn't it? ;-)

You would rather cook a new fresh meal generating more compostables - than re-use old food. ;-P

Yeah...you could look at it that way except now instead of left over night we eat out or eat take out that we bring in or bring in some take out....whatever.

This talk of food is making me hungry!

Val

Hey, this is great... I think I can find a place for a tall, narrow pile and maybe use mesh (or maybe chicken wire?) as an adjustable bin.

John, your compost factory is amazing! The paving stone area for it looks about as big as my back yard (which explains why I was looking for ways to compost in less than 3 square feet).

Thanks for all your information and encouragement.

Lois in PA