It would be possible to write a book on how to prepare hives for winter. Here we try to focus on what we consider the key points.
The first point is to make sure the hive has enough honey stores. The second is that the hive has a queen and enough worker bees. The third is the hive itself, which should have a reduced entrance, some ventilation, and keep out the wind and rain. The fourth is the hive location, which should be sheltered from wind, receive direct sunshine, and not be where mist and frost collect.
A. Does the hive have enough stored honey?
These days we hear so much about the challenges facing honey bees that it sometimes forgotten that the easiest way to kill a colony of honey bees is to allow it to starve. There is nothing mysterious about starvation. A hive that has starved is easy to recognize on post mortem inspection. There are hundreds, even thousands, of dead worker bees in the cells.
Starvation can occur at any time of year. In spring, summer and early autumn there are plenty of flowers in bloom in Britain, but bad weather may prevent foraging and lead to starvation. In the winter, there are few flowers and few days suitable for foraging. To survive the winter a hive must have adequate honey stores. Honey is the fuel that keeps the colony alive and warm during the winter. Honey bees are called honey bees because they naturally store large amounts of honey to overwinter.
Beekeepers need to ensure that each of their hives has adequate honey stores in autumn. It is too late to wait until winter. In Britain, beekeepers should make most of their overwintering preparations in September, October, and be finished by early to mid November.
How much honey is needed? That depends on how long the winter is (longer winters need more honey), how many bees are in your hives (more populous hives need more honey), and also when you will start managing your colonies in spring. If you are prepared to feed your colonies with syrup in March then you can get a colony to successfully overwinter on less winter honey stores. Most colonies that die of winter starvation actually die in spring, running out of food in March and April when their food needs are increasing due to increased brood rearing but when foraging opportunities are often limited due to bad weather: rain, wind, and low temperatures.
If you do not know how much honey is needed then err on the side of ensuring that your colonies have more than they need. It is cheap insurance and will also help with spring build up. With experience, and advice from local beekeepers, a novice beekeeper will learn how much is needed and how this translates to hive weight or full frames of honey. In New York State, where I first kept bees, the beekeepers reckoned that 60 pounds of honey was needed. The winter was long and most beekeepers overwintered populous colonies in 2 deep Langstroth boxes. In Britain the winter is shorter and the colonies have less bees in them, and so less honey is needed
B. Feeding colonies
There are two ways that you can increase the honey stores in a hive. One is to remove empty frames and replace these with full or near full frames of honey. This only works if you have spare frames of honey. You could use this method, for example, if you have 3 hives, 2 with more honey than is needed and 1 that does not have enough. But don’t make the mistake of sharing out the honey in such a way that all your colonies starve.
The other method is to feed syrup. Make up syrup using table sugar (sucrose) and hot or boiling water. Make sure it is all dissolved. Make it as strong as you can, but not so strong that when it cools down it starts to crystallize. Actually, it is not critical how strong it is so long as it is strong. In turning it into honey, the bees will evaporate the excess moisture.
Honey is 17-18% water. One pound of sugar, 0% water, will make approximately one pound of honey. To make 10 pounds of honey, a hive will need to be fed 10 pounds of sugar or more, which will be about one and a half gallons of syrup. It takes a lot of syrup to build up honey stores. It is better if the beekeeper is only using the syrup to top up the hive’s honey stores. When removing the honey crop, it is a good idea to leave enough behind for overwintering so that little or no syrup feeding is needed.
There are many ways to feed syrup, including feeders within or on top of the hive. If you have not previously fed hives with syrup, the simplest method is probably to use a glass jar, with a few 1-2mm holes in the centre of the cap, inverted over a hole in the lid, usually the inner cover hole. The feeder is then covered with an empty hive box and outer cover. Large jars are best as they do not have to be replenished often. A strong hive in need of food can take down a gallon of syrup in a few days. When the feeder jar is empty it can be refilled. If you have a small feeder jar you may need to fill it up many times. This is inconvenient, especially if your hives are not in your own garden.
Bees only take the syrup while the weather is warm. This is the main reason that the hive must be fed in autumn not winter. In addition, warmer weather enables the colony to evaporate the excess water.
There are various things that can go wrong when feeding. One advantage with a glass jar feeder is that you will not drown any bees. But do not allow the feeder to leak syrup outside the hive. This will attract wasps and robber bees. These may be attracted anyway, and it is a good idea to partly reduce the hive entrance so that the guard bees can more easily keep them out.
C. Queen and workers
It goes without saying that each hive should have a laying queen. Brood rearing continues into autumn so you should be able to check that a hive is queenright or not by the presence of brood. When inspecting hives in autumn be extra careful. If the queen is killed by accident, the bees will rear a replacement but she will almost certainly not be able to mate. If you have a queenless hive the best thing to do with it is to combine it with a queenright hive using the newspaper method. Keep autumn inspections to a minimum to reduce the risk of killing the queen by accident.
Hives with very small numbers of workers cannot successfully overwinter, as the workers cannot keep warm. However, in my experience it is possible to overwinter quite small colonies in Britain. At LASI we have no problem overwintering hives in 5-frame medium-depth Landstroth queen mating hives, provided they are reasonably full of bees and honey.
C. The hive
What you should not try to do is to overwinter a colony with few workers bees in a large hive in 2 or 3 boxes. One box, or maybe two, is all that is needed in Britain. Reduce the entrance with a piece of wood to lower the risk of robbing, and to keep out mice and wind. Many beekeepers make an upper entrance to allow damp air to escape and also as insurance against the possibility that a reduced lower entrance will get blocked, such as by dead bees. If you overwinter in 2 boxes one way to make an upper entrance is by putting the top box on a little crooked to leave a gap. This was the method used by the best beekeepers in western New York State, the Davis brothers. The lid should keep out the rain. You definitely do not want rain and wind getting in: ventilation, yes; rain and wind, no.
When I came to Britain after learning much of my beekeeping in a place with cold winters, upstate New York, I was surprised to see some UK beekeepers talking about the need for insulating their hives with polystyrene foam to keep out the cold. In Britain we do not have a cold winter and the hives do not need insulating. In addition, the bees do not keep the whole hive warm anyway. They just keep the bee cluster and brood warm. The bees’ own bodies provide the insulation to do this, and their own normal metabolism provides the heat. Keep the hive dry and ventilated and let the bees worry about keeping themselves warm. If there are enough worker bees and enough honey stores, they can do this with no problem.
D. The location
We have an apiary beside the LASI building. It is on a slope running down to the building. Experience has shown that hives right beside the building, at the bottom of the slope, usually die in the winter while those just 5 yards up the slope do fine. The location beside the building is less sunny and also seems to trap cold air. This shows how only a short distance can make a big difference. The ideal winter location will be somewhere the winter sunshine can penetrate, especially at mid day and in the afternoon. It should also be sheltered from the wind, often by being beside a hedge or building. A hedge or building to the north will not block the sun.
So far I have not mentioned diseases. In LASI we have seen hives not treated for varroa mites dying out in late winter, and also at other times of the year, due to the dwindling of the worker population due to deformed wing virus, a disease spread by varroa mites that shortens the lifespan of individual workers. It is important, therefore, that beekeepers control varroa. However, varroa control is not something than can necessarily be done in the autumn. In fact, LASI recommends that beekeepers treat colonies with oxalic acid via the sublimation method in December, when most colonies are broodless. This is already winter.
F. Final points
In principle, it is possible in Britain to prepare your hives for winter in September and October and not to have to look at them again until April, other than for an annual treatment with oxalic acid in December.
When hives die in the winter, it is not the “cold” winter weather that has killed them. It is the lack of winter preparations the previous autumn, especially the lack of honey stores but may also be due to the lack or worker bees or a queen. Some years, the summer is better or worse for foraging than others and less or more syrup feeding may be required in the autumn. Some autumns may be warm and sunny and the colonies may make honey from autumn flowering plants such as ivy. So be flexible, and give the hives the winter preparations they need for that particular year.
Beekeeping is greatly affected by local conditions. Some beekeepers may be lucky enough to be based in locations where hives almost never need autumn feeding as they make so much honey in the summer. In some parts of the world there is no winter. Here, even if flowers are not available all year round, syrup feeding is possible year round due to the continual warm or hot weather. In Britain we often do have poor summers resulting in the need for autumn feeding. When I lived in California I never fed my hives syrup. I tried but they did not take it as there were always flowers. My first winter in Berkeley, near San Francisco, I was surprised to see significant honey being made on Christmas Day thanks to warm weather and the bloom of Eucalyptus trees.
One final point: in beekeeping there is usually more than one right way of doing things and beekeepers vary in the details of what they do. But there are key points and principles, which I have tried to focus on above.
© F. Ratnieks, October 2016