OK, I’m going to go ahead and fall on this grenade. The question is whether or not to ventilate your hives or to insulate them. There is a common belief that insulating or over-insulating hives is a bad thing. This seems to be based on some field studies years ago that found winter survival rates higher with some non-insulated hives. Maybe the study was flawed. In any case I have tried a lot of different configurations and I have looked at this pretty hard for a long time.
The related issue is ventilation. Open or screened bottom boards and hive covers cracked open are a common prescription in the beekeeping world. Testimonies abound on the benefits of screened bottom boards. My experience is that solid bottom boards are a better way to go. My friends at Bees by the Bay, Harford Honey and Deer Creek Apiaries are all moving to solid bottom boards.
Here are some facts:
- Hollow trees don’t have open bottoms, vented covers, or upper entrances.
- Victor Croker at Australian Honey Company runs 600 production hives in polystyrene hives — and he does not crack open the lids. Honey production is 33% higher than in similar wooden hives under the same conditions. To hear some details on his views regarding insulation (especially in summer) listen in on Kiwimana Buzz podcast #084.
- I have had excellent results overwintering hives in a horse barn, opening the big barn doors on nice days for the bees to fly in and out. When spring approached (in March) I moved the hives out to other apiary sites.
- Screened bottom boards make it easy for small hive beetles to propagate.
- Canadians have to insulate their hives and pack them in 4-packs on pallets for the winter. They cannot depend on Georgia package replacements as the U. S. border is closed to bees. Some big outfits even downsize their whole operation into 5 frame, dense, polystyrene boxes and move to the southern border for the winter.
- Europeans in eastern countries keep their bees in bee houses and in bee house trailers – for protection from wind and cold. And to move to nectar flows.
We don’t open up a gap in the roof of our house in the summer when we have air conditioning going on inside, right? Bees air condition their hives by evaporating water inside the hive in the summer. So why would we work against their efforts by opening a big hole in the roof of their hive and letting their cool air out? Bees increase water foraging in summer according to their cooling needs. Read all about it in Tom Seeley’s book Honeybee Democracy.
Upper entrances and Imrie Shims are great for increasing honey production — but only for the 2 or 3 week intense nectar flow experienced in most locations. These techniques should only be employed for that very short period of time. The remainder of the year keep the top buttoned up.
I know the traditional view is that ventilation is essential to reduce the build up of moisture. This is non-sense. Strong hives in hollow trees or bee hives have no difficulty controlling the moisture within the hive. If you say as do most beekeepers that they found a dead hive and it had lots of condensed moisture in the hive or on the inside of the cover, I will ask you flatly, did the water cause the bees to die? Or was the moisture a follow-on by-product of a weak and dying hive that could no longer control its own internal environment? This is like saying your grandmother fell and broke her hip. Ask her doctor and you will discover her hip broke and then she fell!
Stop blaming moisture build up for killing your bees! Change to solid bottom boards. Change out bottom boards in the spring (like Brother Adam did every spring)! Keep the lids closed! Use upper entrances for major nectar flow only! Trust your bees to heat, cool, and ventilate their hives in their own way. Quit trying to improve on their system.