Thursday, January 12, 2012

Helping a school start composing

Here is a conversation I a had with a teacher who wants to start a composting program. Personal mentoring from a Master Composter was not possible, since the school is out of town, but if you are interested in helping a group start composting you may find this interesting...

I'm a teacher at Esterhazy high school in Saskatchewan and was just wondering if I could be given a few tips on the type of compost bin I should build for my school. I thought it would be good to ask you as you seem to have a lot of information available on your website. I was looking through the document that you had on the website for types of compost bins to use. Could you give me advice on what to use in Saskatchewan as a home economics teacher?

Thanks, Kara

Hi Kara. Thanks for your call about our Composting Bins You Can Build Booklet. I am happy to help you find the composting method that works best for you and your students.

I have to start with a few questions:

What is your input - is it simply scraps from Home Ec class, or will lunch waste or cafeteria waste also be included? The first step in starting to compost is a waste audit, where you collect everything you have for a week and get a rough idea of its ratio of brown to green (C:N) and its volume.

How will waste be collected? If only classroom waste is collected it will be easy to control, but on a larger scale there is an education campaign to plan, plus ongoing monitoring of use and troubleshooting.

Who is maintaining the composting systems? How often, and what about the summertime? This is a major issue because if one person fails to meet their responsibility everyone will be impacted.

What method or type of bin will you choose? I like to leave this up to the people doing the work as it give them ownership of the project and they can switch things up for a new challenge. Some methods are lots of work and no monitoring (trench composting), while others are little work but lots of monitoring (tumbling), and others are in between. All are great learning opportunities.

A bin can be constructed of any long lasting material. Whatever you have laying around can be repurposed to hold waste, as long as it lets a bit of air in (but not too much), is between 1m and 1.5m high, and takes advantage of solar gain.

A high school is a great place to ask for unique ideas for bins. You might get some interesting suggestions, like basketball back-boards, or car doors (let air in by rolling down the window), or bus tires and binders... Teams could have 1hr to build it and the students can vote a design winner, teamwork, compost performance, etc.

I have seen some high-school and college level bins that look great, but are not suitable for the purpose or location and end up becoming a home to wasps, or magpie magnet. A bit of fore-thought will make this a very rewarding project.

I think that is all for now. I am anxious to hear where you are at and discuss options. Composting is not an entry-level waste reduction initiative (not as easy as changing a light bulb), but it is one of the most rewarding.


Hi! Thanks for getting back to me so quickly. To answer your questions: It would be mostly Home Ec. scraps for the time being as I am the one introducing this to the school. As time goes on we may introduce more from other sources. I haven't done an audit but I'm fairly certain we would have a higher green ratio than brown. Could I fix this by adding shredded newspaper and other things?

Compost will be collected in designated bins in my classroom. In the summer it would be likely that the caretakers could monitor the compost bins but I was hoping for an option that did not require much more than weekly monitoring. I have asked the I.A. teacher to have his work experience class create a compost bin that would work well in the courtyard of the school or behind the school (either way it would be placed on top of grass or soil).

The type of bin I choose... well, I was hoping that you could give me some input on that front!

Could you give me a bit of advice?

Thanks, KD

In that case, I would choose a black plastic unit, with small air holes, located in full sun and sheltered from wind. Shredded newspaper, autumn leaves, animal bedding, paper hand towels, and soil are good browns to balance things out. You might also ask students to chop green pieces small to increase the rate of decomposition and reduce odours.

The Earth Machine is a good unit for your purpose - durable and affordable and less likely to be taken when your back is turned. Your municipality may have a compost subsidy program, or a nearby business may be willing to provide the unit in exchange for a bit of advertising.

A wood bin will be a bit more work to keep moist, but if you paint it a dark colour and keep the air holes small and near the bottom It could work well for you. Consider clamping two opposite corners so the unit may come apart into easily managed pieces to make troubleshooting and harvesting easier. Wood lids are more cumbersome as well. The big benefit to having students build the bin is ownership and reduced vandalism.

I think is a good idea to have the caretaker involved in the bin selection as well, to gain their goodwill.

Thanks a lot! This helps a ton. -KD

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