A couple of days ago, I posted about our all-time record high temperature. It was 37 ºC (98.6 ºF) – a temp that’s not too extravagant for many beekeepers, but the city of Calgary had never seen such a hot day. It wasn’t just a record for the date; it was a record for any date since the city’s records began, about 120 years ago. (Calgary is a young town.)
Since 37 ºC was our hottest ever, that tells you that it is normally much cooler here, even in the summer. Usually, it’s pleasantly mild. Sometimes, our summers are really cold. For example, on August 3rd, 2002, Calgary had 5 cm (2 inches) of snow. In mid-August 1993, we had a good, old-fashioned foot of snow and kids went tobogganing and snow-shoeing in Calgary. Today, just three days after nearly hitting 100 ºF, we had 44 ºF in the morning, though we are headed for a high of 68º (20 ºC) this afternoon.
But enough about cold Calgary. Today I wanted to write about heat and bees. My hot blog post on Friday received about twenty comments with advice on how to help bees survive a heatwave. If you haven’t had a chance to read that entry, I think that you’ll find the comments from readers better than the original post which I’d written! I wrote about spraying cold water on hot hives. No one reader came to the unequivocal defense of my ‘hose the bees down with ice water until they chill’ idea, though two people mentioned that they had had wax combs melt inside their hives, breaking and falling.
Heat can bad. Wax melts at around 145º to 147º Fahrenheit (63º to 64º Celsius). Although ambient temperature has never been that hot on Earth (not yet, anyway), it’s possible for heat to become wax-puddling hot inside a box. A friend (Earl Emde) once lost the top boxes on an open-carry truck load of honey supers which he’d pulled on a hot day in the southern California deserts. The temperature doesn’t have to reach the wax-melt point to damage comb, of course. Heat softens combs long before that. The weight of bees and honey can make soft wax stretch and plop to the bottom of the hive, especially with top bar hives (as Erik mentioned on Friday) or with foundationless comb (as Susan wrote).
On Twitter, someone told me that bees know how to manage things on their own and don’t need our garden hose trick. That’s certainly true of wild bees living in trees where thick insulating bark, light breezes, and deep tree cavities mitigate the heat. But most of us no longer climb trees to harvest honey. Our beekeeping is quite unnatural in many ways, including the use of boxes of various shapes and styles. So, we have a responsibility to our bees to take care of them and reduce some of the effects of our unnatural beekeeping.
Here’s a very brief summary of suggestions made by beekeepers. They all offered advice on how to keep bees cooler when it’s hot.
Screens. Susan: “The heat is now so intense in summer that I have not only SBBs but fully ventilated screened tops under the top boards.” ALSO, from JFBeekeeper: “Others use a shin with screened vent holes. Some have bottom boards that you can change between solid and screened bottoms depending upon the season.”
Moving. avwalters: “We moved the hives from an open meadow to an area of filtered sunshine up in the pines.”
Shade. Ray: “I find shade to be the most beneficial so for your hot days and two hives I would erect a nice big sun parasol”
Ventilation. Sassafrasbeefarm: “…others use upper shims with screened port holes which act as a ventilated attic. For those on a budget, a penny or popsicle stick between the inner and outer cover works to vent some of the heat.” ALSO, from Deb Corcoran: “We crack the outer covers up in the back so it reston the inner cover. “
Good air circulation. Steve Williams: “I make sure that my hives are in a place that allows plenty of air circulation around the hive.”
Reflective colour. Deb Weyrich-Cody: “the first thing I’d be doing is paint those hives white.”
These are great suggestions. Our two backyard hives aren’t paying attention to most of this advice, so I’ll have a talk with them – as soon as it gets hot again. Meanwhile, I had a comment on Facebook that hosing bees is dangerous because wet bees will die. They certainly might. My son was watering the hive backs and sides, not the entrances. But I think we might be a little over-concerned about water. Water removes a lot of heat in a hurry. Those of us who have trucked loads of packages in vans have sprayed water everywhere inside the van. Some of it accidentally gets through the package screens. It’s an absolute lifesaver for bees which are overheating. Same with semi-loads of bees – a lot of migratory beekeepers carry hoses to cool their bees off. This is especially important if an emergency stop at a garage is needed and the hives would otherwise bake in the sun.
Our concern about wet bees is valid, but bees are more resilient than you might think. Here’s an experiment that I don’t recommend: Put ten bees into a sealed jar of water. Swish it around and wait a few minutes. The bees will look dead. Maybe they are. Drain the water and drop the clump of wet bees on some paper towels. In a few minutes, they will (probably) twitch, wiggle, crawl, fly up, and sting you in your face for your meanness.
Finally, I want to include a nice email which I got from Dieter. He wanted to send his half-penny’s worth of suggestions, based on Langstroth’s 150-year-old Hive and Honey Bee book.
“It should afford suitable protection against extremes of heat and cold, sudden changes of temperature, and the injurious effects of dampness. The interior of a hive should be dry in winter, and free in summer from a pent and almost suffocating heat.”
Dieter notes: “Suffocating heat wasn’t new to Langstroth. He addresses this, however, by hive design and not with the water hose.” [RMM: I’m sure that Reverend Langstroth would have suggested a water hose if they had been in common use in the 1860s!]
Langstroth also says,
“I am well aware of the question which many of my readers have for some time been ready to ask me. Can you make one of your well-protected hives as cheaply as we construct our common hives? I would remind such questioners that it is hardly possible to build a well protected house as cheaply as a barn. . . . If they are not built of doubled materials they can be made for as little money as any other patent hive, and yet afford much greater protection, as the combs touch neither the top, bottom, nor sides of the hive.
I recommend, however, a construction which, although somewhat more costly at first, is yet much cheaper in the end. Such is the passion of the American people for cheapness in the first cost of an article, even at the evident expense of dearness in the end, that many, I doubt not, will continue to lodge their bees in thin hives in spite of their conviction of the folly of doing, . . . .”
Dieter added, “I have insulated my hives for 3 or 4 years now, long before I found this [Langstroth] reference. When I shared this with other beekeepers in the club they all said it is going to be too hot in the hives in the summer. I tried in vain to explain that the insulation does not only keep the bees warmer in the winter but also keeps the heat out in the summer.”
Here’s the photo which Dieter sent of his own nicely insulated hive: