Keeping moisture levels in a working compost pile within a specific range is critical for proper decomposition.  The rule of thumb you often hear is that the materials should feel damp but not soaked, like a wrung-out sponge.  However, the pile can sometimes dry out or become waterlogged.  Either of these conditions will affect the composting process in a negative way.  Here are some tips for maintaining the optimum level of moisture in your compost pile.

First, let’s talk about why moisture content is a concern.  Too much moisture can turn the compost into a smelly mess.  When this occurs, it’s because oxygen is no longer getting into the pile.  The microorganisms that need air have died off and a different type of bacteria has taken over.  These “anaerobic” bacteria can decompose material without oxygen, but they produce foul-smelling gases in the process.

On the other hand, if there is too little moisture in the compost pile, the microorganisms don’t have the water they need to operate.  They die off and the rotting process slows right down.  If it seems like nothing is happening with your compost, lack of moisture could be the reason.

Your main challenge is getting the right amount of water to all the raw materials.  When you wet down the pile with a hose, you might be watering only the first inch or so, with the middle staying dry.  This is not very helpful.

The best solution is to add water while you are building up the pile.  Dampen each new layer of material by gently spraying it with the garden hose.  Fresh green materials such as grass clippings and kitchen waste probably don’t need additional moisture.

As the organic matter rots, you must continue to pay some attention to moisture content.  You can monitor the situation for yourself by reaching into the compost and feeling it.  Check several spots to make sure water is permeating the material in the center of the pile.

If you live in a rainy climate, the compost heap could get too much water.  This can be avoided by using a container with a cover or rigging up a tarp overhead.  However, if you live in a dry climate, you may want to make the most of limited rainfall by indenting the top of the heap to catch the water.

Weeds growing in the compost can suck up moisture before it gets to the inside.  Prevent this from happening by pulling up weeds immediately and letting them die on top of the pile.

The optimal moisture level for a compost pile is about 50 percent.  This is enough to keep plant matter decomposing at an efficient pace.  Fortunately, it’s not hard to get things right.  If you start off with a properly dampened compost heap, it is more likely to stay that way.  Simply give your compost the small amount of attention it needs and your efforts will be rewarded.