Compost too wet: soggy, slimy, or dripping

If you can wring water out of a handful of compost, it's too wet to work properly.

A compost heap needs to be damp, like a wrung-out sponge, not wet like a swamp. When it goes past that point, the material clumps together, air can’t get through, and things slow to a crawl or start smelling bad. Here’s how to tell if that’s what’s happening and how to bring it back.

Quick fix

Grab a handful from the middle of the pile and squeeze. If water runs out between your fingers, it’s too wet.
Mix in dry browns — cardboard, dry leaves, straw — a bucket or two at a time, until the material holds together but doesn’t drip.
Turn the pile to open it up, and put a cover over it if it isn’t already covered.

The squeeze test

This is the simplest way to check moisture, and it works better than looking at the pile. Take a handful from a few inches down, not just the surface, and squeeze it in your fist. You want it to feel like a sponge that’s been wrung out: damp enough that it holds its shape, but not so wet that water drips out. If you get more than a drop or two, or if the material feels slimy rather than crumbly, it’s too wet.

What causes it

Rain is the most common cause, especially for an open heap with no cover. Heavy or prolonged rain can saturate a pile faster than it can drain, particularly if the pile has become compacted. Grass clippings are another frequent culprit — they hold a lot of water and mat down into dense, airless layers if you add them in a thick pile all at once rather than mixing them in gradually. Sometimes it’s simply a case of too many wet greens (kitchen scraps, clippings) and not enough dry browns to balance them out, which is closely related to the causes of a bad smell as well.

Poor drainage underneath the pile makes all of this worse. If your heap sits directly on packed soil, concrete, or anything else that doesn’t let water through, moisture has nowhere to go and just pools at the bottom.

The fix, step by step

Start by adding dry browns: torn cardboard, dry autumn leaves, straw, or shredded paper (avoid glossy paper). Mix them in throughout the pile rather than laying them over the top, since a dry crust on top does little for the wet mass underneath. As a rough starting point, add browns until the ratio feels closer to two or three parts browns to one part greens by volume — you can always add more if it’s still holding water after mixing.

Turning the pile matters as much as adding dry material. Breaking up compacted, waterlogged clumps lets air back in, which helps excess moisture evaporate and gets the decomposition process moving properly again. If you don’t have a lot of spare browns on hand, turning alone, done every few days, will help the pile dry out gradually just from exposure to air.

Cover the pile if it isn’t covered already. A tarp, an old piece of carpet, or a bin lid keeps rain from adding to the problem while you’re working on drying it out — you’re not trying to seal it airtight, just keep direct rain off.

If drainage underneath is the issue, consider raising the heap off the ground slightly: a wooden pallet, some branches, or a layer of coarse material like twigs at the base lets excess water drain away instead of collecting.

How long it takes