Composting for Schools and Communities

Composting at K-12 Schools Factsheet

Studies estimate that up to 50% of a school’s “waste” can be composted. That is a lot of material! Composting allows schools and communities to reduce, reuse, and recycle. Composting is a way of harnessing and speeding up the natural process of decomposition and there are many reasons to compost including:

Reduces waste and diverts natural resources from landfills
Decreases greenhouse gases (i.e., methane) emitted by landfills
Saves money by reducing the need for waste hauling
Produces a beneficial soil amendment for school gardens, landscaping, and athletic fields, and offsets fertilizer needs
Creates hands-on learning opportunities for students

In a cafeteria, unwanted food of one student may be a treasure to another, i.e., unopened packaged food like milk or snack bars. If a cafeteria has prepared but not served, food can be stored and served the next day or donated to those in need. Schools, along with others, are encouraged to reduce their food scraps by separating excess food for donations and composting the remainder. The composting environment creates conditions to speed up the process of decomposition. Food scraps (wet, green, nitrogen-rich material) and dry, brown carbon rich material are mixed together to create a habitat for the decomposers. These critters are the “work force” and are able to break down organic matter and turn it into a soil conditioner on which plants thrive.

Steps to Take to Start a School Composting/Diversion Program

Form a Team
Promote the Idea
Assess the Situation
Decide on a Strategy
Develop a Collection System
Start the Program
Use Your Product

School Composting - Frequently Asked Questions

1. Separating and composting seems to be a lot of extra work. Why should we compost at school?

Once trained, separation is easy, and will become routine. Compostable cafeteria “waste” makes up to 70% of what is currently going to the landfill. Diverting that waste through composting not only saves money and landfill space, but the resulting compost can be used in gardens to grow fresh vegetables for the school.

2. I don’t think the students will be able to sort out the food waste correctly. How do we teach them?

Daily announcements, class presentations, posters and having helpers in the cafeteria for the first week or two will help transition to food waste composting. Having older students help the younger students learn the process is helpful. Incorporating the science of composting into the curriculum can also help and will provide students with a well-rounded education.

3. What are greens and browns?

Greens are wet materials with high nitrogen content. Fruit and vegetable waste, green leaves, weeds and fresh grass clippings are good examples. Browns are dry materials with high carbon content. Dry leaves, sawdust, paper, and wood chips are good examples.

4. Is composting at school going to smell or cause bad odors?

Well-managed compost should not smell or cause odors. By getting the right mix of nitrogen (wet, colorful materials) and carbon (dry, brown materials), odors will be neutralized. A good starting ratio would be 1/3 nitrogen materials and 2/3 carbon materials by volume.

5. Won’t animals like raccoons, skunks and bears be attracted to the compost pile?

Most pests are attracted to smells that are airborne. If food wastes are covered with a good layer of carbon based materials, smells will be greatly reduced and pests will not find the compost. Also, once it starts heating up, critters will be deterred by the heat.

6. Aren’t the inks in paper toxic? Are you sure it is safe to compost paper?

Some inks in glossy paper can contain heavy metals and should be avoided. It is ok to put in small amounts of shredded office paper, newspaper or other non-glossy paper, newsprint uses a soy-based ink, but other sources of carbon are necessary.

7. Can I compost in the winter?

Yes. Although the decomposition process may slow down in winter, you can continue to add to the pile and decomposition will start back up when spring arrives.

8. Do we need to turn the compost pile?

Turning is not necessary but can be done to speed up the decomposition process. When using a 3-bin system, it keeps you organized: fill bin-1, turn to bin-2 and fill bin-1 again.

9. A plastic fork and straw got into the compost. Is this bad?

No. Finished compost is often screened or sifted and it is common to find some unwanted junk. Be sure to throw these items out before the compost is used in the garden.

10. Everyone has said I can’t add meat or dairy to compost. Why is it OK to add them here at school?

School composting in a 2 or 3 bin system should have enough volume (more than 1 cubic yard) and create enough heat to properly compost meat and dairy items. Most home systems do not get hot enough.