homemade rat proof compost bin that cost nothing

Homemade rat resistant compost bin

Composting is both really easy and really hard to do. Every organic substance left to its own devices rots, the problem is how it rots. Too little air either from being in sealed environment or too much water and anaerobic decomposition happens, and this generally stinks. Depending on what is rotting and what bacteria are doing the work, bokashi is about the only way to anearobic compost and not kick up a stink. Nobody wants to live next to a household whose garden smells like there is rotting dead body or sewage farm. Compost to smell nice needs Air. Tradtionally  this is done by having open compost heaps that are turned regularly, and you are selective about what goes in them. Adding cooked food with it is extra moisture at best makes a compost heap too wet and it starts to smell, at worse brings in rats and other vermin. In an attempt at zero waste and the closed circles of permaculture it seems a waste to throw perfectly good oraganic material in the way of cooked food away because of vermin. So the shangri-la of composting is closed bin with enough air to have healthy smelling composting.

There are several devices on the market from spinning bins to hot bins that are closed but they cost upward of £80 and the cheaper ones are too fragile to be realistically vermin resistant. Bokashi and hot bins require further purchase of woodchips or inoculated bran to keep them working properly. Which are not sustainable if you wish to go moneyless like what we do. Mine cost me nothing to make and nothing to maintain. I found a 50lt blue pest proof bin after a gale rolling around a back road, it was filthy with fag butts glued to oil on the inside. The same bins can be bought in a clean unused condition online for much less than the price of standard compost bin. Mine had a half melted lid, so needs a brick to keep the lid on.  If you are outside of the uk and have to contend with proper wildlife like raccoons and bears the same keg bins are also available with clip top lids which can be locked.

This type of hard plastic barrel keg

If I attempted to compost in one of these the pile would rapidly run out of oxygen and the bottom half would fill with rancid smelling liquid. The worms would die very quickly, and it would be become a mouldy stinking mess. So it needs holes in it. I got out the drill and drilled about ten holes on the bottom rim to prevent liquid build up and a pattern of holes around the side so there is air flowing into the bin.

Put holes around the bottom and in the side with a 1cm drill bit. I did mine in a zigzag pattern. 

The bin then needs to be filled correctly. Like hot bins if there isn't enough air in the mix they go wet and smelly, and like wormerys and bokashi bins if the bottom of the bin collects liquid they start to kill off the good microbes and worms. The first layer I put in my bin was crushed charcoal. This serves a duel purpose of reducing the chance of rancid liquid collecting in the bottom and the charcoal soaks up the nutrient rich liquid to turn the charcoal into biochar. If you haven't heard of biochar I strongly recommend reading up on it. It locks carbon into the soil where the ions aid healthy soil fungi communicate with plants, it also locks nutrients in to a more usable form that doesn't wash away. I started using and making my own biochar two years after attending a lecture off the brilliant Ed Revill from swansea soil carbon. The increased yields and the disease resistance was very noticeable.

bottom layer charcoal

The next layer I use grass clippings. These produce a lot of heat when the decompose and will help heat the layers above.

Grass clippings layer

The next layer I added was from the active compost I have just emptied out of the bin. The first time i filled the bin two months ago i transfered the already active open compost heap the bin replaced. The bin like most other bins need worms and good microbes. When you compost anything that is in contact with soil, worms migrate to the pile. This bin is sealed off the soil so a healthy source of worms has to be added.

worm rich compost added

The next layer was the contents of the kitchen waste bin. It contained quite a lot of apple peelings, it also contains cooked food waste and boiled bones. I don't eat dairy, and we reuse a lot of cooked food, so my food waste bin is about 60% veg.

Food waste including cooked and bones

The next layer is wood shavings from the ferrets bedding. Woodshavings are an important way of adding air to the pile. Everytime I add food waste I add woodshavings or wood chip on top. Any hard dry woody matter will do, such as shedded cardboard and leaves.

The brown layer. 

The lid was the put the the home-made pest proof bin, more layers are added when they come available. After two months the bin was emptied the compost was free of any discernible food waste so was no longer a rat and fox supermarket. The wood chip and straw hadn't fully composted but as I have clay soil the extra roughage is a welcome addition. I transferred this compost into a sack to use in the spring.

not quite fully composted, but good enough to store.

The only other thing I would add is that that I placed the bin on a slab to prevent rats burrowing under. Nothing is ever 100% rat proof, they will chew through anything, but as this type of bin is most pest resistant way of storing food they should mostly try going somewhere else.