New Three Bin Compost System

We finally have an organized system for composting at Lake City Farm.

Our previous composting was done in an old open framework made from extra pieces of cedar planking left over from a deck project.  It worked okay but being open to the elements above and rodents below it became a problem.  In fact, we eventually had a small population of rats using the old garden shed as a 'rat motel' situated right next to a convenient food source in the old compost bin.  This led to the eventual tearing down of the old garden shed and the rehabilitation of the compost heap, along with the permanent 'removal' of the rats.

Since then, we haven't really been able to properly utilize the bulk of our compostable garden gleanings and kitchen waste.  That is, until now.

Pictured above is our new three bin compost setup, seen from one end.  We used a basic plan from The Rodale Book of Composting and adapted it to our purposes by putting it on a concrete base instead of a wooden one.

You might get the impression from the pictures that follow that the whole thing represents a bit of 'overkill' for something as simple as composting vegetable matter.  But we had to find a way to deal with rodents that didn't involve trapping and 'terminating' large numbers of them on a seasonal basis, and also build something that would meet this requirement and last more than a few seasons.  These two requirements led us to consider something a little more elaborate than a heap in the corner of the yard.  An open heap or bin was out of the question.

We constructed the bins out of hemlock, which we hope will provide us with some longevity without, of course, having to resort to treated wood or any kind of paint.  The entire structure was placed on a base of concrete patio blocks held in position on a bed of concrete and mortar.  The first bin (seen with open lid above) which will receive some raw kitchen waste is also lined with 1/2" x 1/2" hardware mesh.  Even though rats are quite good at gnawing through wood, we are hoping that the concrete base and the hardware mesh will act to discourage passing rodents from looking for a quick snack.

We started by excavating a level surface about 9' by 3'.  We then constructed a base with a combination of concrete/sand and patio blocks.  The product we used is meant to be spread 'dry' then leveled and then have the blocks placed on top with more used as mortar between the blocks.  The pictures above show the base with the back and two ends of the bins in place.  We used 1/2" x 6" hemlock for the side slats and spaced them 1/2" apart to allow for air circulation, all held together vertically by hemlock 2x4s.



Next came the addition of the internal dividers made from the same hemlock.  At the front of each divider and the two ends, we used cut down 2x4s to make channels for the front removable slats to slide into.

 

 In the centre and right hand bins we also added  2x4 crosspieces to give the whole structure some needed lateral stability and rigidity.  This was something of a design compromise, since it interferes a little with freely pitching the pile from one bin to the next. We didn't do this with the left-hand bin so at least the first turning of the heap can be accomplished without the crosspiece getting in the way.

The picture to the left gives a more detailed view of the channels on the front which allow the slats to be slid up and out of the way to allow access with a shovel or pitchfork.  Also just visible in this picture is the 1/2" x 1/2" hardware mesh in bin #1.  This will be the bin that receives the raw (and tasty!) kitchen waste that the rodents are attracted to.  We are hoping that the hardware mesh, along with the habit of burying the kitchen waste under a layer of leaves or coffee chaff or something similar, will discourage unwelcome rodent guests from dining in our compost heap.




We constructed 3' x 3' lids from 1"x 6" hemlock held together with hemlock battens.  These are attached to the back of the bin structure with large 8" strap hinges.  The lids are solid (ie. without 1/2" gaps) in order to prevent rainwater from getting the pile too wet and washing away the nutrients.  One final refinement will be the addition of a small hatch in the lid of the left-most bin to allow dumping the kitchen compost bucket into the bin without having to raise the lid.

As you can see, with the slats in place and the lids closed the compost should be pretty well rodent-proof.  Although we've reached the end of our 2012 growing season here at Lake City Farm (except for a few hardy greens!) we've already started using our new compost system.  The dead vines and leaves from the garden beds have all been added.

With the addition of the new compost system to Lake City Farm we expect to keep most of our garden and kitchen waste on the property and not see it going to the municipal compost bin.

Happy composting!