When the weather is hot, your vermicomposting system will heat up, too. Composting worms are living creatures who operate best in a specific temperature range. Let’s find out how you can keep them cool in the warm months of the year.
Our hearty composting worms are designed to handle a range of temperatures. Below 57 degrees Fahrenheit is too cold — worms slow down and run the risk of dying. We don’t know exactly the hottest temperatures they can endure, but we do know this: Too hot is not good.
“Not good” could mean they start to dry up and die. If a few expire, it’s not too big a deal. But you don’t want a bin full of unhappy and, eventually, dead worms.
The best things you can do are to try to keep the temperature down and keep the moisture level up. Also, control the worm population and minimize the vermin.
Keep the Temps Down
What happens if you stand in the sun all day? You will eventually over-heat. Staying out of the sun can significantly reduce the temperatures inside your worm bin. So, put your worm bin in the shade.
You might need to keep your vermicomposting bin under cover anyway due to rain. Depending on the design, certain composters such as our best-selling Worm Factory 360 let in too much water when it rains. Excess water makes the bedding too moist, drowns the worms, and promotes mold and mildew growth.
Additionally, you should allow the bedding to get deeper. Deeper bedding holds the cooler nighttime temperatures longer. This gives the worms a place to burrow if the top bedding is too toasty. You might concentrate your worms in fewer trays (in a multi-tray system), add more bedding, or let the worm castings build up more before harvesting it.
Keep the Moisture Up
You can easily reduce evaporation by keeping your composter lid on (if you have one). A moist sheet of newspapers placed over the top helps keep moisture in, too. The bedding should have the consistency of a wrung-out sponge. If it is dry, you can sprinkle a little water on top, but don’t go overboard with this.
Control the Population
When the weather is warm and there is the right amount of food and moisture, your worms will start having baby worms. First, there will be tiny brown spheres in the bin, and soon the little baby worms will hatch. Some worm owners adopt the policy of letting their worm bin population control itself. If there isn’t enough food or the bin is over-crowded, enough should die off to leave resources for the remaining worms. Other vermicompost enthusiasts like to jump in and remove some of the extra worms so they may live on. You can give them to friends (makes a great gift!), start another worm bin, or simply set some of them free.
Look Out for Vermin and Pests
Any place that is hot and moist allows life to thrive. Look at the rainforest! And Texas! They are teaming with life — crawling with life — because they are NICE AND HOT. You might find your worm bin takes on the characteristics of a rainforest by attracting bugs, vermin and even sprouted seeds. These problems are generally easy to address:
- Bugs: Keep your worm bin healthy, and cover up food scraps. Cut scraps into smaller pieces. If ants install a nest, keep the lid off for a day to scare them off. Fruit flies aren’t too bad unless the composter is indoors — see fruit fly instructions. Don’t let a minor bug invasion bother you — usually, they help break down the food faster. Keeping the lid on deters insects. Learn more about common household invaders including fungi and maggots.
- Vermin: Raccoons and related vermin will come by especially if you throw animal products such as meat, bones, and oils in the bin. Don’t do that. If the lid is loose, use a bungee cord to deter little explorers.
- Sprouted seeds: Sprouts kind of defeat the idea of the composter. Pull them. To prevent them, just avoid adding viable seeds and fruit or vegetable pits, if you can. Don’t go too crazy with this — naturally occurring cucumber seeds, strawberry seeds, sesame seeds, etc. aren’t likely to sprout, but avocado pits have a habit of volunteering to grow.
Your vermicomposting system might have come with a stick thermometer you can use to measure temperature. You can check it if you want, but using your common sense and the tips above will help keep your worm bin healthy in the summer.
Note: If you need more composting worms, just order worms online from Uncle Jim’s Worm Farm.
11 thoughts on “Keep Worms Cool in the Hot Summer Months”
I live in Townsville Far North Queensland Australia and our temperatures often sit in the mid to high 30’s Celsius and don’t drop below 28 for months. This is usually accompanied by high humidity. I put frozen 2L bottles in the top layer of the worm farm to help keep them cool and moist. The farm has pride of place on the veranda because it is the only guaranteed all day shade. I also keep their scraps in the fridge before blitzing them and feeding my little wrigglers. Am I loving them too much and just creating work for myself or do my little friends appreciate my efforts?
From Keeping Composting Bins Cool in the Summer posted July 2018:
“Want to give your worms a treat? Add ice. Place plain ice on top of the bedding or buried in the center of the bin. You can cool and feed the worms all at once by freezing scraps and water together. Place kitchen scraps in a plastic container, add water, and freeze solid. Bury it in the middle of the worm bin. As the ice melts, the scraps defrost, providing a meal for the worms.”
Some of the comments say the ice makes the bin too wet. I guess if you’re in the desert that might not be a problem. Sounds like maybe you’re keeping the 2L bottles closed so the water doesn’t drip into the bins? Smart. I am new at this but I would say your results will tell you what to do. If your worms are thriving, then you’re doing it right
We live in HOT Alabama and we have a bin of worms we’ve been caring for. How do we keep them cool throughout summer? The soil is fairly deep, covered and under our closed deck. Any suggestions on keeping them cool and healthy? Also, what type foods are best for night crawlers? Thank you!
One more question: Should we leave a light on? It seems the light makes it hot. Just confused about this. Thank you again!
Can different worms live together in one bin?
The light is mainly for disturbed or irritated worms. Really only use if your starting a new worm bin and their all new to the bin for a day or two. After that if all is well they should be good and not escaping so no need for the light thereafter.
In the summer, I dump my layered worm bin into a huge plastic storage container (not clear) and add additional shredded paper throughout. I cover the top with a thick layer of paper which I keep moist. Paper grocery bags or brown packing paper I save from deliveries work best. On the over 90 degree (farenheit) days I bury several frozen (sealed) water bottles. I feed very lightly during the heat of summer. I put the bin in shady place.
I love all this feedback and information. I am enjoying “trial and error” for my worm bins. I have put my worms in bins that fit in 2 ice chests. They are insulated, which helps a lot. I put frozen water bottles in the bottom, or sides. After much trial and error, this works great!
I live in Texas …I just got my worms and now concerned as my plan was to put in raised garden beds and in compost section of a keyhole garden which are all in the sun so that my garden plants will get the needed 8hrs of sun a day . . . will the worms be okay in those garden beds?.
I have learned the hard way living in Texas my worms were thriving wonderfully (I had them approx 6weeks) and in a matter of 3days my farm apparently got too hot and the heat dried them all (approximately 2000 worms gone! I am going to start over and try some of the above suggestions….this was an expensive lesson
I have also learned the hard way about compost worms and heat. I live in Scottsdale Arizona and the second summer I had my worms it reached 118° F (47.7 C). I had them in a big plastic garbage can and occasionally put in small frozen bottles of water. Well that wasn’t sufficient and after being away 1 night, I returned to a sad sight. It was like they cooked in all of that heat!
This is what I have since successfully done to keep the worms thriving in the heat :
Purchase an Urban Worm Bin – breaths better than plastic to keep worms cooler
On the hottest days I bury 1 gallon size container of frozen water. Change daily. Also add frozen kitchen scraps like melon rinds, moldy vegetables and fruit.
I also keep the bin moist with burlap fabric and wrap the frozen water in more burlap. I purchased the burlap on line and it is ” table-runner” burlap. Soak in water before putting it on top of the compist.The worms also like to eat it! When it begins to cool off in late September the worms go into compost bins in the ground.