When the weather was turning colder, I wrote about how to keep your worm friends warm through the winter. Now that the heat of the summer is here, it’s time to tackle the opposite issue. I keep my worm composting bin outdoors year round even in our hot summers in the Mojave Desert. It took me several years of reading about vermicomposting before I actually jumped in to try it. The only thing that stopped me was the temperature range these worms need to not only thrive but to survive. Most of what I read mentioned around 85 degrees F as the top end of the survival temperature range for the worms. Obviously, that’s going to be a problem here.
I finally decided to give it a try and last summer was my first summer with my outdoor worm composting friends. They survived just fine. Here are some tricks I use to keep them cool…
Shade – Keep the bin in the part of the yard that gets the first shade of the afternoon. My bin is up against the east side of the house. Use tall plants to cast shade on the bin. I have some tall potted plants that I moved in front of the bin to provide some morning shade. My bin is actually sandwiched between the house and those pots.
Use a Tray System Bin – I use the Worm Factory 360 which is a system of trays that sit on top of each other. The worms move to different trays through holes in the bottoms of the trays. My original plan when I choose this system was to use the top tray as a holding area for an ice pack if needed. I could block the holes with several layers of newspaper and put an ice pack in there. The worms shouldn’t move into the tray if there isn’t any food in there. I actually haven’t had to do this yet but the option is still there.
Use a Large Bin – Providing a spacious home for your worms will give them more room to move away from outter areas of the bin that are too hot for them. Plus, it will give you more room for the next tip…
Extra Bedding – Extra bedding provides insulation which helps regulate temperate swings. This will help the worms both in the winter and the summer.
Insulation – Container gardeners in hot climates will often double pot their plants. You can do the same with a worm bin if you use a large tote system like Rubbermaid bins. Put the bin containing the worms into a larger container. You could even use the space between to add an ice pack.
Color Matters – Dark colors, especially black, heat up fast. Choose a lighter color for your worm home.
Moisture, Moisture, Moisture! – The bedding material will dry out much faster in the hot summer so make sure you check it every day. Mist it to keep it damp like a rung out sponge. Here are some tips for managing the moisture level.
Move it Indoors –In the winter, we only get a couple of days at a time of really cold weather that can harm the worms so bringing the bin indoors isn’t that big of deal. Once the heat is here for the summer, it doesn’t cool off for several months. I haven’t had to bring it indoors during the summer except if we’re going to be gone for a few days. This has more to do with the moisture than the heat. My bin will dry out too much if not misted for several days. Bringing it indoors will help keep it moist. Last week we hit a high of 115 degrees. Yikes! Luckily, it doesn’t stay there long. My bin was already indoors as we were out of town for a few days. When the temps get that high, bringing it indoors is a must.
Cool the Food – I freeze the food scraps before putting them in the bin. This helps start the decomposition process. The food should be thawed and brought to room temperature before giving it to the worms. Sometimes I will put it in the bin when it’s thawed but still a bit chilled. Make sure that you’re not dumping cold food on top of a pile of worms though. Bury it in an area without any worms.
I love vermicomposting but need to keep the worms outside except in extreme circumstances. These tips have helped me keep them there during our hot desert summers. It is possible to produce your own “black gold” worm castings through outdoor vermicomposting even if you live in an area with extreme temperatures. Give it a try!