Newsletter Paragon
Aerated Compost Systems

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A personal story from Peter Moon, in honor of April Fool's Day:

A friend of mine is a perfectionist when it comes to his lawn. A few years ago, while he was at work, I dropped by and put several 1-gallon piles of compost on his lawn to look like the moles had taken over.

After his initial shock, he knew exactly who to blame.

EPA Food Recovery Challenge

City of Philadelphia Department of Prisons -  NATIONAL WINNER

In 2020, the City of Philadelphia Department of Prisons (PDP) diverted over 555,685 pounds of wasted food to compost operations developed by O2Compost, saving the City approximately $19,000 in landfill fees. The composted material was donated to community gardens and church groups, as well as returned to grounds for use in PDP’s orchard and greenhouses. Before composting at the PDP, the department sent food waste to local landfills or industrial garbage disposals.

Philadelphia Prison

To learn more, read the rest of this Client Success Story on our Blog.

Composting 101


Question: I am frequently asked questions like, “How big does my compost system need to be?”

There are at least two answers to this question, the “short answer” and the “long answer”. 

Short Answer: Since you have 8 horses, I recommend that you construct a 3-bin system, with each bin measuring 8-feet wide by 8-feet front to back and 4-feet high. Given that, the total footprint of the structure would be about 25-feet long and 10-feet wide.

Long Answer: “It Depends” on the number of horses that you have now and plan to have in the future. It also depends on the type of bedding that you use. If you use shavings, each bin will need to be considerably larger than if you use a wood pellet type bedding material. Also, do you want to store finished compost under the same roof? If so, we need to take that into account as well. Finally, many of our clients like to construct a multi-purpose building to store other items (feed, bedding materials, tractor implements, etc.). 

Question: Another question I hear a lot is, “How much will my compost system cost to construct?”

Short Answer: Somewhere between $5,000 and $15,000.

Long Answer: “It Depends” on the size of your system, the amount of site preparation, the configuration (top-down or on-grade), the types of materials that you use to construct it, and who does the construction: you with help from your brother-in-law, or a hired independent contractor).

“It Depends” is of course tongue in cheek, but the truth is that every answer relating to composting really does depend on many factors (e.g., climate, site topography, size of the farm equipment, etc.) and considerations (e.g., who will be doing the composting, the amount of time available, the end use for the compost, etc.). When people first learn about the basic composting principles, they want specific answers (engineers are the worst – I know because I am one). 

However, most of what we know about composting is experiential and was learned through trial and error - and there have been a lot of errors along the way (as you will see in Rule #9). As the science and art of composting developed over many years, we have learned to rely on “truths” that generally work out to be right, but not always. 

The message in all of this is three-fold. First, composters need to relax and understand that if we prepare a good mix and add oxygen, it will probably work out just fine in the end. Second, your approach to composting will evolve over time to optimize both product quality and process efficiency. And third, we learn by doing and if a batch doesn’t work out exactly as expected, it’s OK to make some changes to the mix or method and try again. That’s why O2Compost offers technical support. We want you to call us and ask, “What in the heck is going on?”

Closed Ecosystem  


QUESTION #1: Do I need to continue to pump air during the curing phase or can I move the material from the bin and let it cure out of the way of the next batch?

ANSWER: Following 21 to 30 days of active composting, no additional air is required during the curing phase. Yes, you can move the material to a separate pile and, if it seems dry (<50% moisture), I suggest wetting it down a bit as you remix it. When you move the compost and add water, you will likely see the temperature come back up 10 to 20 degrees for a week or so. This is the result of recombining available carbon with available nitrogen and reestablishing porosity in the mix.

QUESTION #2: Should I screen the material prior to or after the curing phase?

ANSWER: If you plan to screen your finished compost, I suggest waiting until the compost is well cured. Leaving the coarse material in the compost will help you maintain porosity so that you get some air exchange to the core of the pile. With curing, there will be some drying of the finished compost making it easier to separate out the course fraction ("screen overs") from the finer fraction ("finished product").

Client Testimonial

Kristen Beigay
Earthen Organics - Easley, SC
Composting Since: 2017


"We love the the ease of the operation, and we love the fact that we get such awesome customer service. We started these piles when it was cold and really wet, it took some education and assistance and Peter was always available to help. We have now partnered with a local vineyard to provide worm castings for 25,000+ vines. We use the O2 system to take the pressed grapes and make an AMAZING compost. The winemaker, grounds manager, and I were thrilled with the smell, consistency and quality of the compost we delivered. Now to do this on a yearly basis! Thanks Moon family for all the assistance!"


New Cornerstone System

Cornerstone Compost System

Owner:  Virginia C.
Location:  Franklin, TN