Hive Ventilation

There are many things in beekeeping which cause furious debate. One part of this, which this demonstrated below, is that different beekeepers deal with different environmental conditions. Here are some extracts from Interviews with Beekeepers on the subject of hive ventilation:

Murray McGregor (Perthshire, Scotland)

Steve: Another thing that crops up a lot, mainly between the UK and the USA, is the insulation versus ventilation debate if there is one.

Murray: I think it’s a debate largely between those who want to be fixed in that way. There is no real doubt that in the Winter insulation is important and ventilation, especially top ventilation, is anathema to the bees. The bees tell you what they want. If you put a board on top of your hive with a vent to allow for top ventilation, the bees gum it up. They don’t want it. We’ve never seen any advantage whatsoever to top ventilation, but a lot of advantage to having insulation. 

Steve: I think from what I’ve heard from discussions over the pond, the idea is that over winter they will get damp without the top ventilation. Do you use solid or open mesh floors by the way?

Murray: We’ve got both.

Steve: I wonder if that makes a difference?

Murray: I don’t think it makes a huge difference, but I would suggest that mesh floors are slightly superior to solid floors from what I can see. But, to compare what happens in the UK, with a relatively gentle maritime climate, to what happens say in the Midwest USA or the Canadian prairie provinces, with severe cold, icing up of the front of the hives at the bottom and many problems that we don’t encounter – to say in the UK that we know what’s best for somebody in North America would be nonsense. They are working in their environment, and they’ve got the best idea of what works for them. 

  However, like everywhere else, there is a tendency in beekeeping to get bogged down in tradition. So, if traditionally that’s the way it’s always been done, then that’s the way it must always be done. In fact, beekeeping is, or should be, like any other progressive craft; open to modern methods so that changes in technology and materials should be exploited to our advantage. 

Richard Noel (Brittany, France)

Richard: I won’t talk a lot about this because for me we don’t have Winters really, we don’t have deep snow on the ground. Mike Palmer, for instance, has three-tiered hives to get the height, and they share their heat because it’s one box next to another, and he has a ventilation hole on top so the bees can breathe. All hives in Canada that are outside have a higher vent hole so that they can fly if they need to. Over here we generally don’t have much snow, not enough to suffocate the bees. I use the Dadant fully ventilated bases that I keep open most of the year. If I get a cold spell and I get time, I’ll close the bases off in early February, to maybe help the early brooding by having less draft. 

  I think ventilation in a colony is a good thing, but I certainly wouldn’t have top ventilations here. The old idea of putting matchsticks on the corners of the crown board, which lots of people on the forums say belongs back with the dinosaurs, was to create an airflow. What you really want to do is make a pocket of air that stays warm, and the minute you make a hole in the top, you get a chimney effect if the base is open too. In our hives in Europe where it’s fairly temperate, we have some snow but not much, you are better off having base ventilation. I believe that a solid base isn’t as beneficial as a ventilated base, but that’s just what I’ve found in my hives. I have used solid bases and find they get dirtier in the winter, but there is a huge debate on it.

Steve: The thing is people who are making their living from this must have found what works for them…

Richard: Yes, it’s area dependant. A lot of professionals I know all have the plastic Dadant bases with ventilation in. It’s kind of a standard thing in France. I think it’s great because you can sterilise them easily and you don’t have to paint them. When something rots in a hive, it’s usually the base that goes first, and you get rid of that with one fell swoop by buying plastic. Which is also cheaper. If you want to close them off you can; I need to do that when treating with oxalic acid. 

Michael Palmer (Vermont, USA)

Michael: I don’t really know what to think about that because our conditions are so different. We have this continental jet stream which comes down the Hudson Bay and freezes us big time in the winter, so we have that, and you don’t. You have maybe a damper climate, so I don’t know what to think. Personally, in my experience I don’t think you need to insulate the body of the hive. Our bees are going through long winters, sometimes four months with no cleansing flight, temperatures in the 20 to 30 degrees Fahrenheit below zero, and the only insulation I have is on the crown board so that respiration moisture won’t condense and drip down on them. 

Other than that, bees don’t heat the inside of their hive, they heat their cluster. If you put thermocouples, heat sensors, in the hive, you can see that once you get a few inches away from the cluster, it’s almost ambient temperatures. So I wonder how much hive insulation is really going to help. We’ve always felt that if you insulate the hive, and you finally get a nice day, it takes longer for the cluster to heat up and be warm enough for them to be able to take a cleansing flight. That’s how it’s always been presented to us. Some beekeepers in the US have double-walled hives with sawdust inside, and the things sweat and don’t do well.

Steve: OK

Michael: I mean look at some of those old-time beekeepers who have had so much success – they have the rattiest old rottenest beehives, full of holes – you’d think that the damn bees would just perish, but they don’t, so I wonder. If you looked in the old literature, like say “the Hive and the Honeybee” or American Bee Journal…somewhere there is a piece by Farrar – he was a professor in somewhere like Wisconsin – and he wanted to show that insulation isn’t necessary. So he took bee boxes and cut out the side panels, so the bees were totally exposed, except they had a roof, and he put a mesh around the body so that predators would not get in and eat the bees. These things went through the winter with temperatures many degrees below zero – they were just heating the cluster.

Steve: Wow

Michael: So do bees need insulation? I don’t think so. What they need is a way to vent away the moisture that they are giving off all the time. In this climate, if you don’t have an upper entrance to get rid of extra winter moisture, the inside of the hive is just soaking wet and mouldy. They need a top and a bottom entrance to get a flow of air. If you want moist air to leave out of the top, you need it to be replaced with dry air, from the bottom. I don’t favour entrance blocks in the winter. I leave them wide open, with a hardware mesh with about a half-inch gauge, so the bees can go through but not the mice.

Steve: OK

Michael: My hives stay absolutely dry.

Steve: You have solid floors, though?

Michael: Solid floors. There’s so much moisture coming out of that top entrance, sometimes on a cold morning, you can see a horizontal icicle sticking out of that entrance, so much moisture is leaving, and it freezes as it comes out. That moisture could be trapped inside the hive.

Steve: Yeah.

Michael: But, you have an Atlantic climate, and we have a Continental climate, so it’s just different; it’s hard to compare. When I’m on the UK forum, and somebody says something I have to keep quiet unless they say something specific about how or what we do here in the US – then I correct them if I can.

Steve: Sure

Michael: But I can’t just say “you’re wrong” because you have a different climate to us.