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What Temperature Should My Worm Compost Bin Be?

Written by Megan Blease

“Summer is coming and my worms are melting!” - something at the very top of our Things We Never Want to Hear list. Hot weather is coming soon, though, and it can be very dry for your worms. If you are located in Arizona, like us, you know all too well how hot and dry it can get in the air and that is exceptionally dangerous for your worms. So, what temperature should your bin be? And more importantly, how do you keep it that way?

Finding the Right Temperature

First things first, your goal is to keep the bin between 55 and 77 degrees Farenheit (or 13-25 degrees Celsius for anyone not in the U.S.). Wow, that’s definitely tricky in our extreme months. Our suggestion is to ensure you have a thermometer to keep track of the bin itself or the area where you store it to ensure it stays within that range.

Maintaining the Temperature

Great, you found a space and you have a thermometer to keep an eye on things. But what happens if you need to adjust it?

Methods to Reduce Temperature

  1. Keep or move your bin to the shade.

  2. Increase air flow by drilling holes or removing the lid.

    1. In extreme situations, setting up a fan can dramatically increase air flow and improve worm comfort but be sure to regulate the moisture, too.

  3. Regulate moisture in bedding (heat dries it out, so try adding more or replace with fresh bedding).

  4. Place a wet towel on the top of your bin.

  5. If kept outside, add ice. Indoor bins will likely collect too much water, which is also bad for our wrigglers.

  6. If possible, keep in a room where the temperature rarely changes (laundry room, basement, etc.).

  7. Reduce the amount of waste going into the bin.

Methods to Increase Temperature

  1. Cover bin with a towel/blanket/tarp.

  2. Create an insulated surround for the bin (one owner suggests using an old cooler!)

  3. Heater - whether a space heater or the heat in your central unit, turn it up for your friends.

Checking on Your Worms

If you’re like me and still need to check on your pals, even after following all of the right steps, watch out for these signs of discomfort:

  1. Seeking new areas inside bin.

  2. Fleeing the bin entirely (RIP to these brave worms).

  3. Excessive waste that is not composting.

If you are still unsure, you may test the bedding yourself and judge how it feels compared to normal or when you first set up the bin. The worms behave normally when everything is working as it should, so let your friends keep you aware of any changes you need to make.

Now What?

Congratulations! You reached the ideal temperature and know how to adjust it, so I know you can keep on the path. Remember, your wrigglers should stay comfortable between 55-77 degrees Farenheit. Don’t be afraid to ask for help if anything changes, but if you manage to set up the environment well and don’t change it too much, you should be fine. Don’t forget to keep yourself comfortable, too. I know you and your worm friends will be fine all season long.

Let’s Go Compost is a community-led effort to make compost bins free and accessible. We upcycle empty bulk ingredient bins into free, food-safe worm compost bins that are donated back to the community. Click here to get a free compost bin at our next monthly pick up event.


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