Compost: From Our School Cafeteria to the Farm

Seeing How Composting Works -- Up Close and Personal

By Eliza

On a weekday afternoon in September, the Sprouts of Hope went on an exciting but smelly field trip. We travelled by car to visit the compost farm where our school's food waste goes after we sort it into barrels in our cafeteria. Meryl Brott, who works in recycling at the Department of Public Works in Cambridge and helped us get our composting program going at King Open, arranged our visit and came with us to the farm.

The compost farm is located in Hamilton, Massachusetts, which is northeast of Cambridge, and it has been running for more than 20 years. The farmer, Nate, was kind enough to give us a very detailed and informative tour of the compost farm.

Here is something new that we learned on our visit:

15 years ago, this compost farm produced 60 cubic yards of compost a year. Now, it produces 25,000 each year. We figured out that means that in 15 years there has been a 415.66 percent increase in how many cubic yards of compost are created per year!

At the farm, they use bulldozers to mix around the compost. They have a big workshop where they keep all of their diggers and materials. There are huge piles of compost outside, but there are also huge buildings filled with indoor compost. One building was entirely filled with a kind of compost called “enhanced loam,” which is a compost/topsoil mix used to grow grass. Its quality is so high that it costs $30 per cubic yard, which is really expensive! Another type of compost that the farm makes is a mixture good for gardening that they call Sweet Peet. Sweet Peet is a composted, aged horse manure similar to mulch.

We drove out in the farmer’s truck to the back part of the farm where a lot of the composting takes place. Most of the compost piles are set in windrows, which are long rows of compost that provide more air and oxygen so that the composting happens faster and the piles are less likely to catch on fire.

Nate carried a huge and very long thermometer with him and every once in a while he’d stick it in one of the piles and show us the heat being generated from the compost pile. Often the thermometer would tell us that on the inside of the pile the temperature was pretty high. [This photo shows the thermometer when it first was put into the pile, and then we'd watch the needle move as the temperature got hotter.] It’s the heat and energy generated by the composting that helps to move the process along. Sometimes we'd see steam coming out of the piles.

The compost farm staff constantly use big machines and diggers to flip the windrows. There are four or five of them next to each other, with space in between to make the flipping easier. These piles take four to five months to fully turn into nutrient rich dirt. Once the compost makes it through its last windrow, it goes into this huge green machine that does the final processing. From there, it heads up, up, up, until it gets tossed out on to the top of the pile that is the final product.

We also found some items -- a plastic shoe and a noncompostable fork -- that should not have been put into the compost stream in the first place.

The most important thing we learned, though, is how important it is to compost whatever can be composted. Before the trip, we didn't know that it costs half as much money in the long run to compost food and yard waste than to send this waste to a landfill where they will rot the “wrong” way. People are paying a lot of money to throw food and yard waste (since these are the two largest types of waste that could be composted) into landfills when they could be saving nearly twice as much money by composting them. This would turn their waste into something useful, produce really good dirt that others can use to grow things, and help to save the earth.