Sunday, June 7, 2009

How To Compost in a School

Several people have asked how I compost all the school's organic matter. They're worried about rats and smell and vandalism and many other what-ifs paralyzing them from action. We just did it, and it was much easier than I thought it would be.

The Bin

The bins the region sells are way too small to be effective. You're much better off making one. I happened to just tear down an old balcony made of cedar boards, so I had the perfect building materials. Our is about 8' long by 5' wide, by 4' deep. It has two separate lids that are hinged. The entire thing is surrounded by chicken wire that goes into the ground a few inches. I would have put the chicken wire on the inside, but the composter got used by other staff before I had a chance. If you can put it on the inside, put the chicken wire across the entire bottom instead of just in the dirt a few inches. Make sure there's spaces between the boards to let in air and rain. The only benefit of the chicken wire on the outside is you can grow morning glory up it.

We keep the bin in a sunny area at the back of the school where students don't hang out much, but it's close enough to get to with buckets of food. My one and only complaint is that in the winter, when the parking lot is cleared, the snow all gets shoved in front of my path to the bin. I often end up climbing a good five or six foot mountain of snow, in a dress, with buckets of garbage. Some people prefer vermicomposting because they don't have to go outside to do it. I like going outside. And, for me, there's a learning curve to tackle with the worms. (And I'm not convinced they'd eat as much waste as we produce.)

If you'll notice, there's no little access door at the bottom to dig out the finished compost, but I find that system encumbersome anyway. I much prefer, just twice a year, to get my rubber boots on and get right into the compost pile to stir things up or get out the "gold".

The Buckets

We have seven pails, well labelled, around the school to collect organic waste. They have signs on them and above them that say exactly what can and cannot go in the buckets. I started with buckets that are similar to our bottle recycling buckets, and ended up with a lot of bottles in them. So I searched out green buckets instead. Students have asked us for more buckets in the hallways, but they're not supposed to eat in the hallways. That's a bit of a conundrum. If I put buckets there, they'll be used, but will I be condoning the hallway eaters?

If you're worried about the buckets attracting mice, I found a mice-away product at the hardware store that, apparently, farmers keep in their tractors so mice don't move into the seats in the winter. It's safe for indoor use (unlike mothballs), and looks and smells like a little pouch of lavender. It might be just that. I tape them to the outside of the buckets so whatever's inside doesn't contaminate the compost.

BUT, the mice and bug issues aren't real concerns because we dump and clean the buckets every night. This literally takes me 10-15 minutes. And we have to stay in the building for 15 minutes after our last class contractually anyway, so I may as well make myself useful. I grab the big bucket from my office, take it upstairs to the staff room, get my washcloth wet and a little soapy, then dump the smaller green buckets into my big one, wipe out the buckets, and move top to bottom. Then I dump the big out outside, wipe that bucket, and return it to my office with the dirty washcloth hanging over the edge. I get my stuff and go. The compostable garbage doesn't sit in the school any longer than the regular garbage, so it shouldn't attract pests any more than otherwise.

I'd include the posters and labels here, but blogger completely messes with the formatting. And I'm a luddite. But you can be creative about it. Basically they say COMPOST to fruits, veggies, nuts, seeds, bread, rice, pasta, coffee, tea, and anything that grows in the ground. And GARBAGE to plastic, paper, metal, meats, dairy, eggs, and anything that comes from an animal. I don't worry too much about salad dressing on salads. There's not a high enough percentage of it to make it a problem.

The Process

To keep the bin outside from attracting pests, I layer the waste alternating between food scraps and yard waste. I keep a garbage can full of yard waste beside the bin. I've discovered, if you're going to do this, that it's a good idea to put a few small holes in the bottom of the garbage can so water can drain out if it starts decomposing before it hits the compost bin. The horticulture teacher tries to keep me in yardwaste, but I sometimes run out. So, where I live, on my street's collection day, I've taken to bringing neighbour's yardwaste to my school (with their permission of course). I can return the paper bags to them right after dumping them, so it saves on that waste too. Adding yard waste is key to keeping out rodents and stopping potential odours.

So every night after I dump the compost, I grab a few handfuls of yardwaste to cover it. Then I close the lid, and Bob's yer uncle.

I fill one side of the composter only, and so far, even though sometimes it threatens to hit the top, it decomposes fast enough that it never actually fills up. The sides aren't separated by any barrier, but they could be. After the last exam in June, I'll stir the mess up, shovel solids over to the other side of the composter, and dig out any compost into a wheelbarrow to be put whereever the horticulture teacher wants it. And on Labour Day weekend, I'll be in to get the rest of the compost out to be spread around, nourishing our gardens.

Time and Material

So altogether, you need a bake sale to buy supplies or a scrap boards and pails drive. You'll need 3 - 8' 2x4s for the bin, all cut in half, and 6 - 8' 2x4s for the lids. Planks - 12 - 8' boards for the front and back, and 6 - 10' boards cut in half for the sides, and 10 - 8' boards cut in half for the lids. Don't forget the hardware (deck screws and four heavy-duty exterior hinges), and a roll of chicken wire. You also need as many pails as you think you'll use, paper for posters and labels, and packing tape to stick the labels on the buckets. And mice-away packets if you're worried about that.

To build the bin, a group of handy students could make it in one or two classes if they're well organized and each group has someone who's used a drill before (a long-shot I've discovered), and you've got access to several cordless drills. Do the front and backs first. Lay down six 8' boards, then lay three 4' 2x4s on top, one on each end and one in the middle. Screw the 2x4s to the boards. Meanwhile, have another group working on the lids. Lay the boards down, and the 2x4s around the edges with one more on the diagonal. Screw those together. Then get the 5' planks (10's in half), and screw them to the ends of the back piece. Stand it up, and screw the side boards to the front. HINT - build it wherever it's going to be put permanently. It will be heavy to move once it's done. And it's nice to work outdoors.

Get kids inside the composter with staple guns laying the chicken wire on all sides and across the bottom. Get other students to attach chicken wire to each lid. Screw a 2x4 to the back edge. Set the lids in place and attach the hinges. I've never described how to build something before, so I hope that makes sense. E-mail me if you've got questions. If you're getting your class to do this, take pictures for the yearbook.

It takes one lunch period to label and put out the buckets. It takes a few weeks of morning announcements. After that you need 15 minutes a day to dump buckets, and an hour or so twice a year to dig out the compost. That's it!

Since I don't have a class that I can do this kind of curriculum with, I built the composter myself one Saturday. At first I had students dump the buckets on a rotation, and I'd just check them at the end of the day. But they sometimes forgot, and knowing I was their backup, they didn't worry about forgetting enough to start remembering! So it became faster and easier for me to just dump them myself. The buckets can never be left sitting overnight or someone will get upset and shut it all down. Also, I can do it without gloves then wash my hands. If students are handling garbage, they should have gloves on - which is an added waste. Finally, at my school, it wouldn't be safe to have them climb that mountain of snow in the winter. Teachers are more expendable.


keb said...

Well its a good process. Nice post! Really informative and I'm now learning from you. Great job!

Anonymous said...

very interesting - here is an intersting green resource as well:

Marie said...

Thanks keb and anon. And thanks for the link.

smably said...

This is great, and I wish my school had had this. I'm inspired to try vermicomposting in my apartment.