We need big compost bins in the garden: to handle the 'arisings' from the meadow and other planting but also to turn it into delicious mulch for better growing, especially for new plans and in the thin soil in the green area.

Design

We wanted at least three bins: one for new stuff, one for turned stuff and one for ready stuff. We have now added two more bays to it - so many thistles!

July 2016: two more bays added.

July 2016: two more bays added.


There are lots of different strategies for composting but we decided that it was better to have some bins soon rather than the perfect ones when we could afford them.  The New Zealand box/bin system is easy to make and use. 

Cambridge Wood Works compost bin kit, made from dismantled pallets

Cambridge Wood Works compost bin kit, made from dismantled pallets

In January 2015, we were inspired by the single compost bins (as kits) made of pallets by David from the former local social enterprise Cambridge Wood Works (CWW) for Rock Road Library Garden and Rock Allotments. He prefers to take pallets apart first and have solid sides without gaps. The base is unlined so worms can come up.


We were short of prepared pallet wood and had lots of old featherboard from a long fence that was about to go into a skip in a nearby building site. We thought this was probably treated wood so would last quite well, and it would have a good patina of age to wouldn't scream 'new wood'. Also, featherboard is light to carry, easy to cut and quick to assemble. 

Like most projects with waste wood, you size the final feature based on what wood you have to hand and minimising the number of cuts you need to make. The bins are therefore quite deep (120 cm), based on the featherboard lengths we had, but they are different widths (around 100 cm) because the pallet slats for the front 'doors' are two different lengths.


Materials

  • Four strong thick square-ish uprights for each bin - from pallets
  • About 11 pieces of featherboard for each side - from an old fence
  • 4 pieces of battening for the slats - from roof repair
  • Lots of slats from pallets, sorted an cut to the same length. You can add to these later - they remain loose.
  • One thick piece of wood for the base of each of the fronts - so the loose slats have something to build onto and gives it some rigidity.
  • Top trim... (optional but probably protects the featherboard from rain)
  • Extra pieces of waste wood to hold the box in place (can remove and reuse it)
  • Masses of high-quality screws, which we bought from CWW's closing down sale.
  • Paint for labels.

Tools

  • Carpenters pencil and T square (optional).
  • Hand saw - our favourite one was rescued from a skip.
  • Workmate for cutting
  • Spirit level
  • Cordless screwdriver - essential. We generally didn't need to make pilot holes.
  • Chalk pens for labels.

How we made it

Simple chalk pen labels on the front slats

Simple chalk pen labels on the front slats

  1. We sorted and sawed all the wood first and had it ready in bundles. 
  2. We took the thick uprights from dismantled pallets and made a simple box frame, one bin at a time with a thick slat at the front base. WE used waste wood to make the top and bottoms before the featherboard went on. We did this in situ to save moving heavy bins.
  3. We used some extra diagonal pieces of wood to keep the box in shape while we made the sides, taking them out at the end.
  4. We attached the featherboard to the sides, one at a time from the bottom up.
  5. Having two people and a spirit level is very helpful. It is good to line the board up with the one you have just done too.
  6. Some of the boards were slightly too short or had chewed edges but we are told this 'gives character'. Best to line them up at the side that will be seen most. We put one screw at either end unless we were a bit worried about the board and used two. Two at the top.
  7. Then we made a 'slot' at the front with some battening left over from repairing the roof, for slats from pallets to slide into. 
  8. Then we added the slats at the front to give it some rigidity.
  9. Then we added more bins to the ones we had made - it might be easier to share a divider wall or place them next to each other - depends on the wood you have available.
  10. You might want to add extra struts top and bottom if the bins are a bit wobbly - ours seemed fine without them. can add them later up.
  11. We also gathered some trim from the top of the fence and added this to the top edges, with some mitering joints to be a bit posh.
  12. Because some people were confused about which bin to add material to, we took a slat our of each bin, painted it with BEDEC Multi-surface exterior blackboard paint and used chalk pens to write 'Feed me', 'Digesting' and 'Ready'. We were also reminded that good composting technique is to 'Wear gloves' and 'Wash your hands' after use - so we added these too.

We might add a blanket on the top in time, maybe just from weed suppressant membrane folded up and held down with bricks. This works well on our allotment.

Useful links:

See the new CambridgeWild webpage for useful links.

Last updated: 1 February 2017