*smack forehead* Yes, you are absolutely right! That is a weakness in the design of our experiment, for sure, and one I failed to fully consider. They do get some light when the fridge opens and closes, but likely not enough to make a big difference.

This design flaws not withstanding, if you compare the results of this experiment to the results of the experiment where we looked at whether seeds need light, the results were quite different. This suggests that temperature, not the lack of light, was the main reason the seeds did not sprout.