Why build it?
Usually, you can incubate plates, flasks, jugs, and bags at room temperature with no incubator needed. But when you are experimenting with new strains, substrates, supplements, and techniques you better know how temperature affects results. Temperature response is a core biological parameter and running off heedless and headless just gets you lost. Been there. Didn’t like it.
When you put a temperature datalogger in with your cultures (you do that, don’t you?) you find that the temperature control provided by your friendly room thermostat can swing three degrees or more depending on where in the room you measure. Monitoring temps near the thermostat reveals fairly close tolerance; at the other side of the room you can have an unacceptable temperature swing.
Now consider growing your cultures at 70°, 75°, 80°, 85° F where the temperature swings five degrees. What can you conclude? I’m not sure. Use precision incubators and be sure. The device detailed here will swing only ± 0.5° F. Incubators from scientific supply houses usually have less precision, much higher cost, and are often not for sale to individual experimenters.
Why build 6 incubators?
Uncontrolled sources of error are to be minimized. Growth rate is known to vary from one batch of growing media to the next, and different mycelial isolates can grow at different rates. So if you want to measure growth rates in response to temperature you also want to minimize growth rate effects caused by different isolates and culture media.
A simple way to do this starts with a large batch of homogenous culture medium and a single subdivided mycelial colony. Then run everything in parallel with multiple replicates. I make up a large batch of plates or flasks or boxes and randomly assign them to different temperature incubators. That way I can be reasonably sure that growth rate differences observed in different incubators is due to temperature.
Also, if I had to run a 70° test, then later a 75° test, then later an 80° test I would have to be more patient person.
By purchasing from the above Amazon links, I will earn a small commission on your purchases at no extra cost to you. Thanks for supporting my work! -Myc
I like to put the control unit outside the chamber, especially if there will be high humidity or even irrigation inside. Yet I don’t want wires hanging where they can short out or get chewed by the cat. So I mount the control unit inside a cheap plastic box attached to the end of the incubator. I found that a cardboard shield hides the wires and protects them from fingers during temperature adjustments (see Figure 2). Since everything runs on 12 volts you would have to work really hard to hurt yourself or your housemates with this system.