What is compost used for?

“What is compost used for?  What’s the difference between compost and manure, or compost and topsoil, or compost and mulch, or compost and…?”

These questions (or some variation thereof) have been posed in Google searches by thousands of McGill Compost website visitors over the years, suggesting a broad lack of understanding on the part of the general public about soil products, in general, and compost products, in particular.

They tell us there’s much more work to be done before compost becomes a solid, steady blip on the soil amendment radar. 

It doesn’t matter whether the compost purveyor is municipal, commercial, or non-profit, or if it’s selling B2C or B2B (or both).   Compost manufacturers, distributors, and retailers can all benefit from marketing programs and advertising campaigns that include a healthy dollop of consumer education along with branding, product descriptions, and price points.

In a recent BioCycle article, Dr. Sally Brown reminds us that “… feel good sayings without quantitative information to back them up doesn’t always help to move the product. To a city engineer, these feel good statements can make you sound like a new age guru pushing a dietary supplement rather than a knowledgeable resource with alternative solutions.


To be fair to all the OGs out there, in the early days of the composting industry, the only thing we had to peddle was feel good. There was little bona fide research or hard facts that demonstrated compost’s effectiveness to a customer,  just anecdotal evidence and side-by-side field photographs comparing compost and no compost applications.

McGill’s own economic impact studies, conducted in the early 2000s and funded by the state of North Carolina, were among the first to investigate dollar benefits related to compost use.  The research may have been simple by today’s standards, but it validated information our agricultural customers had been telling us for nearly a decade – and provided a solid foundation for the growth of our compost sales program into high-value markets.  (READ: the 2000 and 2001 McGill study reports)

But dollars and cents are only one part of compost’s amazing story that started with fertilizer value, but now just keeps going and going and going to include everything from food waste recycling to stormwater management to carbon storage.

Yet, the abundance of compost’s benefits seems to be a message that hasn’t been told loud enough or long enough or often enough to reach the ears of the majority.  There are still too many stormwater plans out there that don’t fix the soil as a critical first step,  communities that burn or bury compostables, and farmers who don’t use compost on conventionally-managed fields.

Talking who, what, when, where, and how when promoting compost is good.  But today, when a potential customer, policymaker, or specification writer is searching the web, s/he also wants to know the why — backed up with facts and figures.  Why is compost the right solution for their particular problem?   Why is it a better choice than amendment X, Y, or Z?

What is compost used for?

Adding macro and micro nutrients, building soil organic matter, replenishing and sustaining soil microbes, improving nutrient uptake and plant disease resistance, creating pore space, adjusting pH, absorbing rain impact energy, degrading pollutants, storing carbon —  it’s a lengthy benefits list for a single product that just happens to be “green.” 

Fortunately, unlike decades past, cyberspace is now loaded with scientific studies that provide meaningful data related to compost performance.  This is news the marketplace needs to hear.    

For example, it’s true to say compost alleviates compaction.  But when presenting to engineers, would it not be better to also include a link to or slide of this table that compares compost’s performance to other solutions, showing it among the best?

Or when a city is making decisions about its stormwater management strategy, why not share some comparative costs per gallon retained for various retention solutions discussed in Milwaukee’s Green Infrastructure Plan (see Page 63)?

“Compost will hold 10 times its weight in water” is good for visualization.  But how does it help a stormwater system designer calculate potential water and cost savings for mandating compost use vs. rain gardens or storage tunnels?  

These are the types of statistics a decision-maker needs to see when considering options:

  • A typical compost is about 50% organic matter. 
  • Every 1 percent increase in soil organic matter adds 16,000 gallons of water-holding capacity per acre foot.  
  • At only 2 percent organic matter, soil can hold all the rainfall from a typical rain event — around 1 inch or 27,154 gallons. 
  • A 1 percent increase in topsoil organic matter also stores about 60 tons of carbon per acre.

While specific numbers may vary depending on the study and/or source, the core message — that compost can be the better choice — remains constant. 

Researchers say the majority of today’s buyers do their due diligence and make purchasing decisions before reaching out to vendors for that all-important “first touch.”   If true, it’s more important than ever that brochures, point of sale displays, websites, or other outreach tools make the effort to quantify as well as entice. 

The environmental benefits of compost use are still an important part of the message. But the days of the easy sell to a predisposed customer base are long gone.  Now it’s time to win over everyone else.

Expansion of both B2C and B2B markets depends on the industry’s ability to effectively silence skeptics, motivate fence-sitters, and educate the uninformed — while keeping products (and services) cost-competitive.

Facts and figures will play a big role in that education effort.

Granted, there are lots of challenges ahead, and we do need more research of relevance to compost users to help fill quantitative gaps.

But composting is at an unprecedented place in its own history.  For the first time, the general public is eager to know more about what composting and compost use can do to positively impact a wide variety of issues. 

“What is compost used for?”

For the continued growth and wellness of the industry, research-based numbers need to be part of that all-important answer. 

What is a composting facility package plant?

In the water/wastewater treatment and composting industries, a package plant typically refers to a small, prefabricated unit dropped on-site, ready to connect to the larger system.  A McGill composting facility package plant is different.

Since McGill doesn’t build small facilities, its “package” is actually a set of blueprints and specifications for an industrial composting plant pre-engineered to meet the specific environmental containment, throughput, and feedstock requirements of the owner.

Actual construction may include prefab and off-the-shelf components, but there is likely iron going up at the site and concrete to pour, too.

While the owner is still responsible for site-specific engineering,  all other aspects – structure, process, operating procedures, etc. — are provided with the package.  Initial crew training and start-up supervision is included, too.

Pre-engineered McGill facilities ensure efficient, economical operations because they are designed by folks who have been successfully building and running trouble-free, 100,000+ TPY commercial plants for nearly 30 years.      

Got food waste?  We’ll take it. 

Here’s what you need to do to get ready for food waste composting 

(Also view WE WORK FOR FOOD WASTE on SlideShare) 

Not every composting facility is using a technology with the oomph to take on the full range of biodegradables common to food waste.  McGill is one of a handful across the county that will accept it all. 

McGill accepts food waste, including dairy and meats.  We take certified-compostable cups and other serviceware, too.   Dirty napkins and pizza boxes, paperboard/cardboard, broken pallets  – toss it all into that container bound for a McGill composting facility. 

But there are a few things you need to do before jumping feet first into organics diversion. 

  • Composting generally costs less than landfilling.  Look around for any and all biodegradable wastes that can go to composting along with that food waste.  
  • Get a handle on total generation volumes of biodegradables.  You can’t get a quote, plan for storage or make meaningful forward progress until weekly or annual generation rates are determined.  Our Estimating volumes for composting SlideShare title can get you started on either a DIY or professional waste audit. 
  • Get a quote for composting services based on the total compostables volume. 
  • Figure out how you’re going to separate the compostables from the other recyclables (plastic bottles, aluminum cans, etc.) and trash.  The composting stream has to be “clean.” That means no non-compostables.  Contamination makes the compost unsalable.  Because the ability to derive revenue from compost sales is one reason composters can offer lower tipping fees, intake customers (like you) are the beneficiaries of diligent source-separation.   
  • Identify vendors for compostable serviceware and other products.  Determine costs to switch to an all-compostable food service environment.  Going all-compostable will eliminate most common contaminants, scratch the need for multiple trash and recycling receptacles in food service areas, reduce the cost of penalties for contaminated loads, and make enforcement of separation policies so much easier.    
  • Develop a collection, separation, and storage strategy. 
  • Confirm all assumptions, develop and finalize the project budget. 
  • Develop and initiate a training and enforcement program for participants, whether they be employees, customers, or residents. 

If you’re in a region served by a McGill composting facility: 

  • McGill will haul your food waste and other compostables if you generate enough to fill a big roll-off container or tractor-trailer load every few days.  Some health departments may have rules governing the required frequency of food waste collection.  Check with yours.  Regardless of local rules, you don’t want food waste sitting around for long periods of time.  If you are a low-volume generator, contact a third-party hauler who specializes in bin and cart collection.  Your public works department or local/state recycling coordinator may be able to give you some names.   
  • One cubic yard of food waste weighs about half a ton.  Our minimum load requirement is 40 tons.  We’ll haul smaller loads, but you’ll be charged the 40-ton minimum.  That’s why it may pay for you to look around for other organics to toss into the composting bin along with the food waste. 
  • If you want to haul yourself, take a look at McGill’s requirements for vehicles and drivers. 
  • To find out if there’s a McGill facility near you, find our locations here. 
  • Here’s how to contact us. 

If you’re not in a region served by a McGill composting facility: 

To find a composter in your area, contact state and local recycling coordinators or solid waste divisions.  There are also searchable directories online, like Find a Composter. 

Confirm what these operations will or will not accept, then base your waste audit and separation strategy planning on those findings. 

To compost it yourself: 

For high volume generators,  McGill offers package plants beginning at 35,000 tons per year throughput.  

But for low volume generators with sufficient space and people-power, on-site composting may be an option, offering the resulting compost for sale or giveaway to customers, employees, or the broader community. 

If exploring this route, do yourself a big favor and eliminate open-air composting as a consideration.  The last thing any company needs is negative PR from an outdoor compost pile gone wrong.  Opt for some kind of enclosed or in-vessel system, like those offered by Green Mountain Technologies.   

Also know that composting beyond the backyard requires professional management.  It may also require state or local permits.  For program stability and to ensure both paperwork and process are done right, even a small community food waste project relying on volunteers for the bulk of the labor force should consider putting a paid, trained, and certified specialist in charge of the composting operation.