How to overwinter your beehive

In most places, there won’t be any flowers available for bees to forage on during winter.  So it’s very important to prepare your hive for the winter.Frederick Dunn is a beekeeper based in the northeastern United States, where winters are long and very cold. He gives some great tips on keeping your colonies safe throughout the colder part of the year.
He covers the following topics:

1. What factors affect overwintering?
2. What do the bees do during the winter?
3. Winter stores - what resources to the bees need to survive winter?
4. Ventilation & insulation - protecting your hive and maintaining airflow.
   
   

What factors affect overwintering?

It's a good idea to connect with local beekeepers to understand specific overwintering practices for your area. It is helpful to source bees that are adapted to your region so that their biological reproductive rhythm is suited to the typical climatic conditions in your area.

How well a colony will survive through winter in cold climates depends largely upon:

• The number of bees they have in the colony.
• The health and condition of the colony.
• The resources available for them inside the hive throughout the winter.
• How well the hive is equipped to deal with the cold weather (ie: in terms of ventilation, insulation, etc).
  
  

What do the bees do during winter?

Towards the end of the summer, the colony will stop producing foraging bees, and instead produce fat winter bees. These live longer than foragers, and their larger bodies help to generate heat and insulate the brood and the queen throughout the winter months.

You need to be sure your hive is queened right coming into fall/autumn. If there are at least 10 bees per minute arriving back to the hive with pollen, it’s usually a good sign that your queen is laying. If in doubt, you may need to inspect the hive.
The bees will form a cluster, and start at the bottom of the hive. As the season progresses, they will gradually move upwards, feeding on the honey stores from the bottom up. They will typically advance 1mm per day.

You will need a large cluster of bees in your brood box going into winter, spanning over several frames and about the size of a soccer ball. The cluster needs to be big enough to generate sufficient heat to keep the brood warm throughout winter. The bees will maintain a brood temperature of 94 to 97℉ (34 -36℃ ).

In the depths of winter, the colony’s metabolism slows down and they can go into a state of torpor - a bit like hibernation. Once temperatures increase and they fly out, they will immediately eliminate the waste that they’ve been storing in their bodies.

Winter stores

In cold climates, it’s usually best to use two brood boxes. Either one deep box and one medium, or two deeps. Set up your hive accordingly during spring. Consult with local beekeepers on how much a colony typically requires to get through winter in your area.

You don’t want to have excess space in the hive, as it will require more energy for the bees to keep warm. If you have harvested honey from a super, remove the super and allow the bees to clean off any excess honey. Flow Frames should be drained of honey and wrapped inplastic for storage. You can leave the super in an unheated storage shed for the winter. 

After the super has been removed, you should be left with a deep brood box at the base, and a medium or deep super or brood box on top. The bottom brood box should have brood in the center, followed by pollen, with honey stores at the edges. The box on top will only be for honey.
A sugar feeder at the top of the hive can help the bees last through winter if they’ve exhausted their honey stores. Ideally, the emergency feed should be installed before winter so that you don’t need to open the top cover when it’s cold. Fred prefers feeding dry sugar in winter, rather than syrup.

Ventilation & insulation

Fred recommends not having any ventilation at the top of the hive (eg: an open-top entrance). This can create a draft, causing the heat generated by the cluster to escape. There should be ventilation at the base of the hive for oxygen to enter and CO2 to be expelled. The bees will also need to be able to leave and enter the hive when the weather is warm enough for them to fly. An entrance reducer or a mouse guard can help to reduce drafts and keep intruders out of the hive. 

During winter, it’s not uncommon to see a number of dead bees and the landing board, and sometimes close to the front of the hive. You may need to clear dead bees from the entrance occasionally to make sure it doesn’t get blocked.

You can add insulation to the top cover. Polystyrene or wood shavings can be used for this. You can also wrap the hive with extra insulation. The outside of the hive should be well sealed and waterproof. You may want to strap your hives down in case of high winds. If a beehive gets covered in snow, check the entrance for holes and pathways. The bees will usually maintain pathways out of the hive to allow airflow, while the snow provides extra insulation for the hive. 

Don’t open the hive during a cold winter! This risks chilling the brood and killing your colony.
You can check the position of the cluster by listening with a stethoscope, tapping gently on the side of the hive to hear the cluster buzz, or by using a thermal camera. The closer the bees are to the top of the hive, the less honey they have left.

Want to learn more? This video is taken from our online beekeeping course -TheBeekeeper.org. Check it out for lessons on all aspects of beekeeping from the world’s experts.