Curious, if this is so, why do so many use the screened bottom board? Aside from the IPM aspects anyway. I am building my first Warre hives and planed to use screened bottoms. Can you elaborate more on this?If you choose to put a screen bottom in your TBH, do it for reasons other than ventilation. Bees use a form of evaporative cooling to keep their hive at an appropriate temperature. They do this by carrying water into the hive and allowing it to evaporate. If the bottom is wide open, the lowest the hive temperature can be is the ambient air temperature.
Bees keep their brood at 93-95 degrees. If ambient air temperature exceeds that, and the bees can't use evaporative cooling, that will not be pretty.
I am curious how the bees in the south handle this. When I lived in UT we used swamp coolers because the humidity was so low but now I, along with the OP am in the south and there is no such thing as evaporation in this incredibly humid environment.Bees keep their brood at 93-95 degrees. If ambient air temperature exceeds that, and the bees can't use evaporative cooling, that will not be pretty.
I believe you will find that evaporative coolers are successfully used to cool greenhouses in North Carolina. This document suggests that appropriately sized evaporative coolers could be reasonably expected to drop the temperature 12 degrees in July in Concord NC:I, along with the OP am in the south and there is no such thing as evaporation in this incredibly humid environment.
I have. When I first moved here I had a genius idea to create a misting system on the back deck. When turned on, instead of cooling as I was use to out west instead I just got wet. It takes a dry environment to cause evaporation. Apparently the bees have a better grasp on this then I do.You can even test it yourself, on a small scale. Use a spray bottle to mist water on your face on a hot day and report the results.
MB, do you mean a completely open bottom? And what about SHB? I noticed in my hive last year the little buggers would run from the bees and fall to the bottom and hide in the corners or any crack small enough. I figured with a screened bottom they would at least fall out of the hive.If it is screened and not blocked a package is likely to abscond. And if it's wide open, as already pointed out, it may keep them from being able to cool the hive. In my experience it does little or nothing for Varroa.