The weather has turned bitterly cold but the worms are happy. It’s not Hawaii for the them but the bin temps are in the preferred range of the worms.
The OSCR plans call for an electric heat cable but I felt that there was too much material in the bin that’s potentially combustible. Paper and cardboard make up a good portion of what we feed the worms. These materials are normally wet, but we have seen them dry out and we didn’t want to take a chance. So, we decided on installing a hot water heating system.
We felt that a 5 gallon plastic bucket would be sufficient water to circulate and the buckets will take temperatures that are pretty high. We started out with an aquarium heater in the bucket but it didn’t heat the water very fast nor very hot. We found the following on sale at our local Southern States:
We happened to have a high volume aquarium pump that we planned to use for brewing vermitea.
We bought 9′ of heavy wall plastic hose. There was no specific structure in the plans to accomodate the hose. We wanted it to be stable and still allow the contents of the bin to continue to settle without hangups. Here’s what we came up with:
securing the heating system in the bin
We attached a 1×3 at each end of the bin and drilled holes to hold 1/2″ emt pipe. We drilled two holes in the bin so that the hose could be inserted just under the emt.
This is what it looks like from an end view:
We then secured the hose to the emt with electrical ties:
The hoses were attached to the pump after drilling holes in the lid of the bucket as shown here:
This is what it looks like after adding some insulation and an electronic thermostat:
The thermostat has a probe. A hole was drilled in the bin to insert the probe which was positioned in about the middle of the bin between the emt pipes. As the contents of the bin have settled we have had to dig around a little to raise the probe a couple of times so far. We don’t want the probe to go too far down or we won’t be taking readings in the right area.
The heating system has been working well. The outside temperatures today are in the teens with wind chills around zero. The thermostat is set at 70 and the compost thermometer is showing temps in the 60’s. The probe’s reading fluctuates around 70 within a degree or two at most.
We are very happy with the heating system. If we build another bin in the future, we will likely make some minor changes with the design.
This bin looks so incredibly well thought out and safer that some I’ve seen. I’m also old enough that bending to rake out compost isn’t comfortable – let alone getting compost in the mouth like Mark! We use the submersible water heaters in our horse water tanks all the time. They aren’t always the most reliable appliances – always seem to go out when the weather is the coldest and you have to be careful to always keep them under water. I’d keep a backup one on hand – but it does seem like it would work. Can’t wait to see how well your worms do in this bin. Jean[an inner circle friend]
wormfarms are great, i farm worms because they make my vegetables huge