In order to achieve the high temperatures that facilitate the optimal conditions for rapid and thorough composting, air circulation is critical. Even if you are doing passive compost, as I most often am, your bin design and maintenance routine should allow air to pass through your compost pile. With most commercial bins, regular fluffing or turning will help keep your good bacteria oxygenated and prevent your material from getting matted or compacted. Air vents on the sides will allow cool air to come in and help vent off excess heat generated from the intense metabolic activity in the core of your pile. Sometimes it’s not enough, however. You can create additional air pockets by adding poles, corn or sunflower stalks, or sticks at various positions within your compost pile or design a simple ventilation system using drilled PVC piping.
As discussed in more detail elsewhere, if you are doing hot composting and have availed yourself of an open bin system, regular turning is the best way to keep air flowing. But even here, ventilation can be used to encourage air movement and maintain hot conditions. Here’s a simple illustration of a turning I did today, which also provided the opportunity to install my new compost smokestacks:
1. My arsenal of tools includes a light rake, a spade, and a garden claw.
2. I gently raked off the top layer of wood chips and set aside in my wheelbarrow.
3. Next, I clawed out the entire contents of my bin.
4. I tried to keep track of top, middle, and bottom contents by arranging bags and buckets in the order removed.
5. I then returned the contents to my bin in reverse order. So what was on top now goes to the bottom, and vice versa. The material gets fluffed in this movement. Brown and green materials further mix and mingle.
6. Once the contents were piled back up in full, using a long wooden pole, I bored wide holes in strategic positions.
7. Each hole received a length of PVC piping with lots of holes drilled in.
8. For aesthetics and neighborly concern, I dressed the top layer with the woodchips.
My smokestacks should foster airflow from the bottom of my pile and help distribute heat more evenly. Remember: aerobic conditions offer the ideal breeding and metabolic environment for the most efficient bacteria that do the heavy lifting in your compost pile.