Beekeepers
interpret winter as the time to leave the bees alone and hope they make it
through to Spring. This is not entirely true. A deadly threat
beekeepers should be conscious of is moisture build up in the hive. A
strong colony can tolerate the cold during winter but add moisture to the mix
and the colony will not survive.
As hives are sealed up for the winter, the temperature difference between the warm inside of the hive and the cold outside can cause moisture buildup at the interface of the warmer and colder air. Respiration from bees and evaporation from honey are other influences on moisture within the hive. Ventilation helps in deterring this dangerous threat from building at the interface, condense and rain down onto the bees and brood below.
As hives are sealed up for the winter, the temperature difference between the warm inside of the hive and the cold outside can cause moisture buildup at the interface of the warmer and colder air. Respiration from bees and evaporation from honey are other influences on moisture within the hive. Ventilation helps in deterring this dangerous threat from building at the interface, condense and rain down onto the bees and brood below.
One of the simplest ways to provide
ventilation to relieve moisture is by opening
their upper entrance on their inner cover. To open it just leave the gap under the hive top (they are a little longer than the hive) on the side of the hive with the entrance.It will it provide an additional
entrance if the bottom hive entrance gets cluttered with snow or debris as well
as an escape for building moisture. An alternative method is propping up two corners of the inner cover
with Popsicle sticks or thin pieces of wood. The Popsicle Sticks provide
larger gaps for moisture escape but not large enough for bees to get through.
If using the inner cover alone still
isn’t enough to control moisture then there are several other resources and
tricks you can use.
- Place an empty medium or shallow super above the Inner Cover and fill with crumbled newspaper or hay. They help absorb excess moisture as it rises through the center hole in the inner cover. You will need to check the newspaper often to make sure it doesn’t get too saturated. If it does then just replace it with fresh newspaper. If you are worried about the bees getting up with the newspaper, then all you need to do is cover the center hole with a small piece of 8-mesh or 5-mesh hardware cloth.
- Replace the inner cover with a Wintering Inner Cover or a Vivaldi Board. Both can be used year round and can be manipulated to control moisture.

Vivaldi Board: It comes with screened
opening on both short sides which provide constant ventilation all year while
still protecting from robbing insects. For feeding it works roughly the same as
the wintering inner cover but instead of filling it with sugar candy, you
sprinkle a ring of dry sugar around the central entrance and place the provided
screened box over the sugar to protect it. Placing a folded burlap sack over
top absorbs any excess moisture, using it to soften the dry sugar making it
easier for the bees to feed on. Of course you can also just use the burlap sack
to absorb moisture, but just like the newspaper you will want to check it and
replace if it gets over-saturated.
- Replace your hive top with an Ultimate Hive Cover (available for 10 frame hives only). It has been designed to provide ventilation via the air space built into the walls. It does not require painting but you may need to place something heavy like a brick or rock on it to keep it from coming off in bad weather.
Even though moisture is a big issue
most beekeepers experience during the winter, with a few simple tricks it
doesn’t have to be. Using tools like the wintering inner cover and Vivaldi
board, moisture can even use to your advantage when trying to provide feed for
your hive. When temperatures get below 55 degrees F you do not want to open up
your hive otherwise the heat they built up will escape. Tools like Vivaldi
Boards or Wintering Inner Covers provide ways to assist with moisture control
without fully exposing the hive to the cold. Just like everything else with
beekeeping, it’s just a matter of observing your hive and seeing what their
needs are before you decide what method(s) to try.