Overwintering My Hives
As I prepared this fall to settle into the winter routine of beekeeping, I did a lot of reading, reflecting, and discussing with others the reasons for colony failure in the winter. My understanding is that colonies fail to overwinter for several reasons, including cold temperatures, starvation, and excess moisture. Following are some thoughts on dealing with these problems; some are my own ideas, others I have learned from the masters. (Of course, disease, pests, or predators will also kill a colony, but that will save for another day.)
From what I understand, bees in a hive don’t usually die from cold alone; they die from being cold and hungry, or from being cold and wet. It therefore seems to me that the best way to overcome the effects of cold is through an integrated strategy … yes, help them stay warm, but also deal with the starvation and excess moisture.
Starvation is hypothetically easy to deal with – just ensure they have adequate honey stores to make it until the dandelions bloom in the spring. Easy, right?
Oddly enough, colonies will sometimes die of starvation while there is still food enough in the hive. The reason for this is that they don’t break cluster, and fail to find the honey that is just outside of their reach. Therefore, it is important to not only rely on the hive weight or number of frames of food stores, but also to occasionally open the hive to see if the honey is where the bees are, and move frames as needed to assist.
Because the bees consume their food stores to generate heat, the colder the weather, the greater the chance of starvation. And of course, moisture is increased as well.
Moisture is the hardest of the problems to deal with, as the source of hive moisture is the bees themselves. If there are bees, there is moisture; it is a product of the respiration and energy consumption processes of the bees. I know of three ways to deal with moisture in the hive; reduce, retain, and/or remove it.
First, moisture in the hive can be reduced. Make sure there are no liquids (such as syrup) in the hive. Make sure there are no water leaks into the hive. Reducing the bee population will reduce the moisture, but that might be counterproductive. Keeping the hive a little warmer through insulation or good siting will reduce the food consumption, thereby reducing both moisture and the chance of starvation.
Second, moisture can be retained. There are various strategies for doing this; the basic idea is that any moisture that is in the hive, but not in contact with the bees, is a non-issue. So, many beekeepers make quilt boxes to put wood shavings or dry leaves in the top of the hive. The dry material absorbs the moisture at the top (water vapor rises), and effectively removes it from the bees’ living space. Moisture boards are used for the same purpose, as is dry sugar.
Third, moisture can be removed. Having the hive tilted towards the front, allowing liquid moisture to drain out, is a first basic step. But the real problem is the moisture at the top of the hive, as it will tend to drip down on the bees and chill them. This moisture is most effectively removed by ventilation. Most beekeepers find that a combination of top and bottom ventilation is needed to keep the hive dry.
My Hive Setup
As I prepared my hives for winter, the choices I made were all guided by the desire to maintain adequate warmth and food, without allowing excessive moisture to accumulate in the hives.
First, to ensure they have enough food, each hive has at least 10 deep frames of honey, and I poured 10 lbs. of dry sugar in a feeder rim at the top of the hive as well. The beauty of the sugar, in addition to the food value, is that it will help dry the hive.
Above the feeder rim, I have a notched inner cover, providing ventilation and an upper exit. Above the inner cover, I have a moisture board, then 1″ of blue board insulation, and then the top cover. The blue board is there to keep the hive top as warm as possible, in order to prevent condensation at the top. Hopefully any moisture that condenses up there despite these efforts will be trapped either by the moisture board or the sugar.
At the bottom of the hive, I have a screened bottom board, with the drawer closed. Until I believe there is excessive moisture in the hive, the drawer is going to remain closed, in order to keep the cold out. But I do have a little ventilation from the bottom, both through the reduced entrance and through the sides and back of the drawer. Between the bottom board and the bottom box, I have a slatted rack, which provides a little buffer airspace and tempers the wind blowing through the entrance.
The hives are placed in direct sunlight, with a windbreak behind. I did not wrap my hives with anything, as I believe that might make the moisture problem worse, and will reduce the potential for solar gain when the sun is shining. But I did strap a layer of blue board insulation on the north side only, since there is no solar gain to be had there.
I think most beekeepers would prefer to have more insulation. Part of my thinking is that I prefer condensation to take place on the walls of the hive, and for that it needs cold walls. Moisture that condenses there will run down to the bottom of the hive, where it can drain out. This is better than condensing at the top, where it can drip on the cluster of bees. I may regret my choice to not insulate better, we’ll see.
That is how I have setup my hives, and I am hopeful it will work, but remember I am a first-year beekeeper. I’d love to hear your ideas, write me at firstname.lastname@example.org. Until then, I hope you stay warm, dry, and well fed, just like your bees. ~ Greg