Problem: Pile has a rotten or an ammonia type odor.
Reason: Not enough air in center of pile, or too much moisture. An ammonia smell indicates that there is too much green material in the pile.
Solution: Turn the pile and add more dry (brown) material. Take care to add grass in thin layers.
Problem: Critters and/or fruit flies.
Reason: Fruit and vegetable trimmings are too close to the surface.
Solution: Make sure to bury these materials deep into the pile, and cover with other yard wastes.
Problem: Pile not decomposing.
Reason: Could be that the pile is too dry or doesn't have enough green materials.
Solution: Add water, if needed. Also may need to add more green materials, like grass or manures.
Problem: Pile is damp and earthy smelling, but won't heat up.
(NOTE: This is not necessarily a problem! If the pile doesn't heat up, it is probably still decomposing — just not as quickly as possible.)
Reason: Pile could be too small-it needs to be at least one cubic yard in size. Or pile could need additional green material.