A compost pile should be moist, but not wet and slimy. A soggy compost pile is an indication that something has gone wrong.
The compost pile might have become waterlogged or there may be too much fresh material in the compost. Either way, both scenarios mean there is too much moisture in the pit. Fresh materials like vegetable peelings have high water content, and if too much of these materials are added, this will lead to compaction, thus filling spaces inside the pile with water instead of air.
This condition encourages anaerobic bacteria to thrive in the pile, which then causes the rancid smell associated with compost.
For those new to composting, it might be discouraging to see a compost pile turn soggy, but here are ways to save soggy compost.
Turn your compost to incorporate air and then recompose its content. Add carbon-rich or brown material as they will help absorb excess moisture. This includes grass clippings, dried leaves, straw, sawdust, and forest duff. Use a shovel or pitchfork to break up any large clumps as this will help improve aeration.
To make sure that this does not happen again, be mindful of the amount of moisture in the compost. Moisture management starts with evaluating the weather. If it tends to be rainy, make sure to cover the compost.
A compost pile should also have proper drainage. If a bin is being used, make sure it has holes so excess moisture can flow out of it. Just ensure that nothing is blocking these holes. If the compost is just a pile on the ground, dig out a shallow trench around it so the excess water flows away from the pile.