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Best Ways to Dry Out a Wet Worm Bin

worm bin moistureWhen your worm bin is too wet, what are the best way to dry it out? At Uncle Jim’s Worm Farm, we have heard this question many times. The vermicomposting bin’s moisture level is crucial to worm health. We have been raising worms on our farm in rural Pennsylvania for more than 40 years. In that time, we’ve developed a simple protocol for drying out a wet worm bin. Let’s start with the primary question: is the worm bin too wet?

A wet worm bin starts to smell awful! The acid balance in the bin can get thrown off. The worms can get sick and die. They breathe through their skins, so they can drown in a too-wet bin. The worms might try to escape in large numbers.

Composting Bin Moisture

When you keep Red Worms or European Night Crawlers to eat your organic trash, you take them on almost as pets. The worms will work hard to turn kitchen scraps and yard trimmings into fertilizer. You also have a responsibility to provide a suitable home. In the worm bin, the worms are dependent on you. They need a dark home with sufficient drainage, bedding, and food. Worms thrive in a slightly moist environment. Therefore, you need to check the bedding’s moisture content regularly.

Professional worm growers and serious hobbyists use a hydrometer to measure moisture. Gently stick the device into a part of the bedding where there a few worms. When the measurement is complete, you should see a number in the “moist” range (approximately between 4 and 8).

However, there is no need to run out and buy a hydrometer. Simply pick up a small handful of bedding and squeeze. The bedding should have the consistency of a wrung-out sponge. If water leaks out between your fingers, it is too moist. If it feels flaky or crumbly,  the worm bin is too dry.

Reasons Why It’s Too Wet

A bin gets too wet usually because something is out of balance. The food scraps you add are moist; the worms are eating away in there, and the drainage and air holes are supposed to compensate. However, you might have fed the worms too many high-moisture foods. Perhaps the drainage holes are blocked. Look carefully at the drainage holes and clear them if they are blocked. Bins designed for vermicomposting have enough drainage holes — and they may have a spigot for releasing accumulated water.  If you have a home-made bin, see if you need to drill or punch more holes.

Some of the moisture evaporates and escapes through air holes. If you made the bin yourself, you might need more air holes. Purchased bins should already have enough ventilation — either holes or a loose-fitting lid.

Leaving your worm bin out in the open exposes it to rainwater. Rain can come in loose-fitting lids. Water might even splash through the air holes! Worm bins should be kept under shelter, such as an awning, a covered patio, a shed, or a garage. Worms can drown if the bin floods.

Placing a worm bin blanket on top of the bedding helps regulate moisture.

Dry Out the Worm Bin

Here are the best ways to dry out a vermicomposting bin in three easy steps:

  1. If there are puddles on top, sop them up with paper, paper towels, or clean rags.
  2. Stop adding very moist scraps until the problem is under control. Avoid fruits, especially melon flesh. If the worm bin has a spigot, open it until the problem is solved.
  3. Add more bedding. For example, use coconut coir, pure peat moss, or shredded black-ink newspaper (see other bedding ideas). Gently sprinkle a few handfuls of dry bedding on top. Stir very gently so you do not hurt the worms. Bedding should be an even level of moisture, with no dry or wet clumps. Break up wet clumps. You can stir it again the next day if there are still clumps of dry bedding.

We have heard of removing the lid and blowing a fan directly into the bin. You may need to shine a light on the top of the bin to keep the worms in. This may have limited effectiveness, but you can try it for a few hours and see if it helps. This will probably only address moisture near the top of the bin.

Still Having Problems?

If you dry out the bin but still have an odor or dying worms, see our Worm Bin Troubleshooting Guide.



7 comments on “Best Ways to Dry Out a Wet Worm Bin

  • I use emptied coffee cans. If you don’t have any ask around to friends and/or coworkers, I’m sure you’ll find some

  • I removed the lid from our indoor worm bin and rotated the contents hourly for 4 hours, it really helped to dry it out and the worms aren’t trying to escape any more. Also, I just placed some melon rinds in the bin to attract mites for removal, worked like a charm!

  • Rebecca Miller says:

    How do you check on the moisture level in a narrow, deep worm bin such as the compost tower in a Garden Tower 2? I’m more worried about too dry (Phoenix, AZ) than too wet, but until the tower gets filled most of the way, I have no way of using a hydrometer or feeling the bedding.


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