The Three Bin System

In a previous posting, three main types of bins, the three bin system (also referred to as a turning bin) was detailed. In this type of bin, the piles are built to the height of the fencing in two of the three piles. Turning the piles is easy in this type of system. Notice in the picture below that the two bins on the left are filled with compost and covered with black plastic to retain moisture. Move the compost from the middle pile to the open space at the right which will aerate the pile. Now move the pile from the left hand bin to the now vacated middle, empty bin. When turning the pile from one bin to the next, use a hay fork or some other device with significant space between the tines. This will allow for easy release of the material from the fork.


Here are some notes from the sign next to the three bin system at Gove, Denver Urban Gardens' demonstration site on the west side of Colorado Blvd. just north or 13th Avenue:.

• The unit is made of recycled wooden pallets wired together with t-post for support, if needed
• Additional pallets across the front of the unite and chicken wire on the inside will keep materials from spilling out
• Wood pallets are widely available for free (more information to follow)
• The system is modular, meaning you can add extra pallets as needed
  

Starting an Outdoor Pile

When building an outdoor compost pile, there are several options for the container (or structure) which will hold the pile in place. Here are a few options which are on display at Denver Urban Gardens' Gove Demonstration site on west side of Colorado Blvd. between 12th and 13th Avenues. The first picture (to the right) is a cinder block, three sided bin where the blocks alternate in their position. The openings in the blocks allow for air to reach the pile and ensure that aerobic (oxygen requiring organisms) continue to thrive, keeping anaerobic bacteria, which cause a smelly compost pile. The open front allows for easy access to turn the pile, again maximizing aeration.


Another option shown at the Denver Urban Garden (DUG) demonstration site is the single, three sided wood rail bin. Similar to the concrete bin, this is a single bin, with three sides. Both of these bins are slightly taller than 1 meter high (about 3 and a half feet). The slats on this bin allow for some air flow and encourage aerobic organisms as well. Just as with the concrete bin though, turning the pile is essential.

Lastly, for those with the space and resources, a three bin system (three wood slat as seen in the picture or three cinder block bins next to each other), offers greater flexibility. In the case of the cinder block bins, ensure that the pile has maximum aeration. If you make a three bin system, leave one of the three bins unused for future "mature" compost. The two simultaneous bins will reduce in volume by nearly 50%, which will fit nicely into the third, open bin when they have finished decomposing. For a three bin system, it is important to have enough matter to build two separate piles. For most urban backyard composters who choose to make an outdoor pile, there probably will not be enough material to adequately fill two cubic meters of volume.

Questions, Problems, Concerns?

Post questions, problems or concerns on this website (blog) and members of the community can reply for everyone to see. If your compost pile is just sitting there like a pile of refuse, write a post explaining what it is you are doing and what happened leading up to the problem. If you have a fix for other people's issues, write a comment on their post and help them activate their compost pile.

Beautiful Compost

Roberto's compost video