What is a compost bin and how does composting work?

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Apr 24, 2006 (Updated Jul 19, 2011)


The Bottom Line Composting can help the environment and your garden.

How compost bins work
A composter is usually a bin or barrel that holds plant matter or very specific type of animal product like egg shells or excrement. You put green plant matter, brown plant matter, and an activator in this container, mix it well and let the microorganisms do the rest. Microorganisms begin to feed off this matter and produce more of themselves. This heats up the pile, sometimes up to 140 degrees, and disinfects the pile through that prolonged heat. After the process is over (2 weeks to 2 years) you are left with a dark soil that can be used for various things like a soil amendment, ground cover, etc.

What are the needs of a compost pile?
Water- about the consistency of a wrung out sponge.
Nitrogen rich greens (and/or compost activators rich in nitrogen)
Carbon rich browns.
Oxygen- this is done by turning the pile as well as having slots in the compost bin for air to go through.
Heat- the microorganisms do the job faster if the pile is hotter, so don’t expect too much activity in a cold winter.

Also keep in mind that the more surface area the microorganisms have the faster they can decompose the pile for you. Sometimes you may want to mulch the material first if the pieces are too big.

The three types of composters.
The basic container- This is a box, round container, or some sort of container that does not come apart nor is it meant to move. Usually they do not have a bottom. In order to turn the pile you need to manually shovel it around. The other option (which is pretty much only available online) is using a compost turner.
The multiple bin system- You can buy this or just make it yourself. It is just like the above container but you have multiple bins instead of just one. You start with the first box with the pile. After the pile has heated up and cooled then you transfer it to the next container by a shovel or pick. Do this 3-5 times and you will have compost in no time.
One system I use acts like a multiple bin system called the bio-stacker. It have 3 layers that form the walls but the walls can be un-stacked and moved. What I do is remove the top wall and place it immediately next to the remaining two layers. I then transfer some of the pile (while mixing in nitrogen rich stuff and watering it) until the first piece is full. I then do the same thing with the remaining two layers until I have successfully transferred all of the pile. It is nice because it takes up less space and is easy to use.
The rotary system- These are cylindrical containers that hold the material. These cylinders are mounted to a support structure and can spin thereby aerating the pile inside. It is the most expensive type out there but requires less effort from the user.

Materials
There are a couple of options for containers. You can just use chicken wire for a quickly set up bin. Wood is another relatively cheap option to build out of, just make sure it is a dense wood or something that will not decompose easily. The third option, which is the most common, is recycled plastic. Many of the compost bins are made out of recycled plastics and are therefore quite durable.

Activators
I will refer you to my article on activators (see below) but basically an activator is a substance high in nitrogen that increases the activity of the microorganisms in the pile.

Where to find composting tools
I have bad news for you, the big names in home improvement do not regularly carry compost bins or tools. The best resource is going to be the internet. Occasionally a local nursery will have equipment in the spring or some of the bigger home improvement may have a day set aside for a composting event.

Benefits of composting
-Less trash.
-Make your own soil amendments.
-Improve the environment.

Cons of composting
-Takes up space.
-Takes time to do it.
-Will smell if not properly balanced.
-Requires a strong back.

Other reviews you might be interested in.
Life time compost tumbler An awesome compost tumbleer for an awesome price, better than others I've looked at.
Bio-stacker compost bin.
What Should You Know About Compost Activators?

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