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.