Help Your Worms Beat The Heat

Understandably, a topic that seems to come up a LOT this time of year is that of overheating worm bins. It is something I’ve had to deal with myself up here in the ‘Great White North’ (ok, so Southern Ontario isn’t really all that far north), so I can only imagine how much of a challenge it must be in more southerly locations.

Generally, once temps start to creep up towards 90 F (~ 33C) Red Worms start to reach their upper threshold of heat tolerance and can start to die if additional measures are not taken.

I’ve added this post in our ‘Reader Questions’ section since I’ve included a really helpful email from one of our readers (who wishes to remain anonymous). She has provided some great ideas for how to keep a vermicomposting system – specifically a stacking plastic bin – cool in the summer. I will add some additional thoughts as well.

Hi Bentley,
Being a newbie I was totally unprepared for a heat wave last month,
and I unwittingly killed maybe 1,000 worms. I did a lot of web
surfin’ and question askin’ and wanted to share what I’ve learned to
keep my Can O Worms cool(er). Temps have been in the mid 90s in my
area this week and I’ve had no worms die!
This should work for any multi-tray, continuous flow type of system
– make sure your unit is in deep shade
– place lots of damp shredded newspaper in the very bottom of your
unit – this will prevent a mass suicide (this would have saved my
worms last time!)
– lots of damp newspaper on top of your working tray
– If you have any empty trays, put them under your full/working trays
and fill them with damp crumpled newspaper – this will give your lil
worms more places to cool off.
– open the spigot to get a little more airflow
– make sure all the ventilation holes are not plugged or covered.
(The vent holes are small and few in the Can O Worms.)
– remove the lid and drape a wet old white sheet (or burlap or any
light fabric) over the unit. This will draw cooling air into the unit.

Our friend sent in another great suggestion yesterday, which is to place frozen water bottles in the system to help keep things cool. I think this would be a great way to combat heat, and it would be relatively simple to keep a constant rotation of these bottles going.

Here are a couple more suggestions I’ve thought of:

  • Keep the worms in a very well ventilated bin, such as that made from wooden slats – if you add water regularly, the evaporation will really help to cool things off
  • Dig a deep hole in a shady location and lower your bin down into it – be sure to leave some space around the outside for air flow – alternatively, you could simply create a worm pit vermicomposting system directly in the ground

Do you have any strategies for helping your worms beat the heat? If so please write in a share them – I’ll gladly add a second installment on this topic if I get some more ideas.

[tags]worm composting, vermicomposting, composting, worm bin, compost bin, heat wave, summer, red worms, compost worms[/tags]

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  1. Wow, these are great suggestions. I think I inadvertently killed off my worms due to heat as well. I had actually contacted you some time ago because I had problems my bin. At first it was too wet and had invited a gnat infestation. I had then mixed in dry soil to dry up my soggy bin and had lost a lot of worms in the process. Well, the population was recovering it seemed and the gnats were under control as well, except a week or so ago when I checked there were no worms anywhere. The apartment shouldn’t have gone higher than 85 degrees based on our A/C settings but this is Arizona and the bin sits close to the front door… so too much heat is all that I can think of. I’ll try better next time …in FALL =(

    • james
    • June 28, 2008

    Hi everyone I have done a lot of research on worms and curiousty is out there but not weather related. I have created my own worm bin out of a plastic tub. I started out good with a pound of redworms I have had them for about a month. I did not have an odor problem until I gave them pine apple and cantaloupe these mites seem too consume more food than the redworms do so I threw most of the cantaloupe out and noticed something sprouting from the fresh head of the pine apple, this thing 2-3 ” inches tall and about half a dozen of them. The pine apple is mostly gone but this spore thing has got me puzzled, thats my issue. Now for the people use drums ice cream buckets any bucket may have too catch rain water and give your red worms a shower it will not hurt them at all just make sure it drains out properly and you have something too catch that for your garden etc.

    • Jo'
    • June 28, 2008


    My strategy for helping my worms beat the heat is to place a few ice cubes (2 per sqft) inside the bin, on top of the bedding. I do this in the middle of the afternoon either each day or every other day. It seems to do the trick and my worms survived this past heat wave. Make sure you that extra water has a place to run off to at the bottom. You wouldn’t want to drown your worms.

    Hope that helps!

    • Bentley
    • June 30, 2008

    Thanks for the comments, guys!
    James, I’d certainly love to see a picture of this mystery thing (for lack of a better word) sprouting from your pineapple. Sounds like some sort of fungus to me.


    • Amos
    • July 29, 2009

    This is great info, but I live in Las Vegas. Is my only option to have a bin indoors?

    • Bentley
    • July 30, 2009

    Hi Amos,
    I’ve never vermicomposted in vegas (sounds like fun though – haha), but if I was going to try (and do so outdoors), I would probably try a ‘vermicomposting trench’ in a very shady location. Having the system buried in the ground should help to keep it cool and moist.

    • Tina Corona
    • October 10, 2013

    Hi, I I am getting ready to move my Worm Inn outside and was wondering if I too could dig a hole and place the in halfway in the ground? Would that interfere with the aeration?

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