When building a compost pile, it is extremely common to experience some difficulties along the way. However, the overall process of controlled decomposition is a simple one, and the solution to your problem is likely straightforward. Below are some symptoms of poorly executed compost piles, as well as some suggestions for improvement.
The compost smells like rancid food: A distinct odor coming from your compost heap can indicate an excess of nitrogen (fresh or green material) or too little oxygen. If you suspect that the compost is too wet, turn it frequently so that it can aerate properly, or consider moving it to a drier location. If you believe you've added too much nitrogen, balance the content by adding more carbon-rich material like paper or dry straw.
The compost isn't getting warm enough: If the compost is too cold, it will not break down. Most exposed compost heaps over 3' x 3' work seasonally, meaning they slow or halt the decomposition process during winter months. But large, covered or contained heaps should stay warm regardless of the weather. If you believe your heap is too cold to break down, consider enlarging, covering or containing it. If it is still too cool despite this, you might not be adding enough moisture or nitrogen. So incrementally increase the amount of damp, fresh material you turn into the heap.
The compost pile is attracting animals: Animals and insects will be attracted to accessible food. Remember that bones, meat and dairy should not be added to any pile. Also, cover fresh food scraps with a layer of carbon-rich material such as hay, leaves or paper. If you notice ants living in or around the compost, your heap may be too dry. In that case, add more fresh material or moisture to the pile.
The heap has a matted, damp texture: If you use a lot of lawn clippings or leaves, it is easy for a compost pile to aerate poorly. These fresh, flat materials can easily cling closely together; not providing room for oxygen to move through the pile. If this seems to be the case, aerate the pile by turning or fluffing the compost. You may also choose to diversify your compost materials, as too much of one thing can slow the decomposition process.
If you are still struggling with your compost heap, please take the time to review the process. You can learn the basics of composting by reading Composting in Five Steps.