This kind of humidity probably wouldn’t be an issue if I could find a screened bottom board or a screened inner cover somewhere. Or I suppose I could try to build one.
Imagine how difficult it is to dry honey inside such a humid hive. My ventilation rim helps, but a screened bottom board would probably help out even more.
UPDATE: The ventilation rims pull moisture from the hive by allowing an air current to flow over the inner cover hole. But as you can see in the video, humidity can still build up inside the hive underneath the inner cover. So here’s a little something I do with my hives when I know we’re in for some sunny days:
I pry up the inner covers just a bit and slide Popsicle sticks through the corners of the hive. This allows more hot air and humidity trapped under the inner cover to escape, yet the crack is small enough to prevent predatory insects like wasps from getting in. Another simple, cheap and effective beekeeping tip brought to by the good folks at Mud Songs.
August 20th, 2011: I put my hand in front of the entrances of all the hives today, no entrance reducers on the hives, and I could feel the humidity pumping out of every one of them. I’m convinced now that all my Langstroth hives in St. John’s, Newfoundland, maybe even my nucs, would benefit from as much ventilation as possible at least during the month of August. That means: 1) Screened bottom board, 2) Ventilated inner cover, 3) Ventilation rim. Those three together would be dynamite. Add to it a slatted rack and follower boards (aka dummy boards) and the hives will be boiling over with healthy bees and tons of honey. That’s my best guess, anyway.
February 2019 Postscript: I don’t use slatted racks because I don’t have the carpentry skills to make them and I can’t affordably buy them from any commercial supplier. I’d use one if I had one, but I’ve gone almost nine years without using slatted racks and I’m doing alright, so…?
I don’t use screened inner covers, though I sometimes add empty moisture quilts to my hives during extreme heat spells.
I’ve used commercially manufactured screened bottom boards and my own homemade junky looking screened bottom boards. Honestly, the ones I made from scrap wood worked just as well, if not better. The bees don’t care. I only have two or three of them banging around, so most of my hives do fine without them. But they help keep the hives dry, even in the winter, though I don’t have enough experience to have the most informed opinion about that.
(Note: Screened bottom boards in Newfoundland aren’t used for mite counts because the island of Newfoundland doesn’t have Varroa mites. We’ll have them someday because the measures in place to prevent them from getting on the island are not adequate, especially considering that honey bees in Newfoundland have never had Varroa and all the diseases that come with it and are probably the healthiest honey bees on planet Earth. But as of February 25th, 2019, Varroa hasn’t yet made its way to Newfoundland. When it does, that’s the day I quit.)
I pretty much just use ventilation rims and moisture quilts for ventilation, a nearly identical configuration to the D.E. Hive, and that seems to work well for me most of the time.
I just remembered that I also stick hive tools and one-dollar coins underneath my inner covers just like I do with Popsicle sticks to provide a little extra ventilation from time to time.