Composting

Composting is an important item in all school gardens and an integral part of the 5th-grade science curriculum. We collect 4 kinds of composting going on in our schools which are described below:

Black Earth Composting - Food waste is now starting to be composted from all school cafeterias! 5th graders are beginning to sort their food waste from lunch and depositing it into our new Black Earth bins. All of WPS school cafeterias have been using Black Earth bins to

Leaf pile - in the fall students rake a lot of the leaves that fall down from the trees in the schoolyard and collect them in "Leaf Piles" that are allowed to break down in place. Some of the leaves are also used for the "Browns (Carbon-rich materials)" are added to the Earth Machine along with the "Greens (Nitrogen rich materials)" of food waste and fresh weeds.

Earth Machine composter - all elementary schools have. Plant waste and some paper from the school cafeteria kitchens is collected and added to the Earth Machine. When adding food, some dry leaves from the leaf pile are also added to provide aeration and bedding for the decomposers so that the process remains aerobic

Yard Waste - collected by Watertown's DPW during the spring, summer, and fall months and directly from the schools sometimes after a garden workday. Yard waste can be anything that doesn't go in the other types of compost due to the presence of weed seeds (weeds gone to seed), roots of invasive grasses and plants that will survive in the Earth Machines in each garden, sticks and bark and branches that take a long time to break down and some plant waste that may be diseased

Others - What happens to the rest of our food waste and compost paper products that doesn't fit into the Black Earth bins or leaf piles? Alas, a lot of food waste and other compostable materials go out the dumpster and to a landfill or incinerator, and the carbon is lost back into the atmosphere as CO2 or methane mostly. But our DPW is working hard to change that! stay tuned