Because air penetrates only the first few inches of the pile, it needs help to reach the composting pile's center. Therefore if you suddenly get that nasty rotten egg smell around the compost, it means that anaerobic bacteria are moving in, and it's time to give your composting pile more air.

In hot composting, plenty of air is essential to develop the high temperatures needed to kill harmful bacteria and speed the process of decomposition. Here are a few ways you can add air to your compost pile:

1. Turning:

The most effective method of introducing air is to turn the pile with a garden fork. Lift the material from the top and sides, toss it into the more active center of the new pile; then add the partially decomposed center to the outside. In other words, take the composting material from the outside and the top of your pile and exchange it with the composting material in the middle of your pile.

2. Stirring:

If you would rather not do the work of turning a pile, try stirring it with a stick instead (much harder to achieve desired results). However, this method won't distribute the air as evenly, so the composting process will be somewhat slower.

3. Aerator Tools:

At a garden center you can buy an aerator - a rod which has flaps on the one end which is pointed and a handle on the other. Holding the tool by the handle, you jab the pointed end into the compost pile as far as you can and then pull the tool back outwards or upwards. As you pull it back out of the pile, the flaps unfold to pull up and loosen the materials. Using an aerator tool is easier than turning, and this procedure produces more air than stirring .

4. Air Stack:

Another approach is to build your compost pile around a perforated pipe, a bundle of long twigs, or a tube of wire mesh (chicken wire works well) standing on end. In other words, stand one of the three in the middle of your empty compost bin, then add the compost material around the item. This allows the air to get to the center of your pile between turnings. With air stacks, you can skip the turning, but the pile won't heat up as efficiently.

5. Elevated Compost:

Most compost piles rest on bare ground, but instead you can build it on a raised platform of loosely spaced boards and allow air to be drawn up from the bottom. If you elevate your compost, however, be sure to sprinkle garden soil throughout the compost to introduce those essential soil bacteria.

In other articles I explain the other two components necessary for proper composting: how to keep just the right amount of moistness for best results and what can AND cannot be added as food to the compost pile.