Should I Close Up My Screened Bottom Board During the Winter?
Simply put, if you are in the northern half of the US, or areas with significant amounts of snowfall, it’s a good idea to cover up the screened bottom boards for the winter. This can be done with a sheet of posterboard, corrugated plastic, etc. Insert it into the opening of the bottom board, and use an entrance reducer to help hold it down so the bees can still easily come and go. Insert it when temperatures are routinely below freezing at night, and remove it when nights are routinely above freezing.
For the southern half of the US, covering the screen is not necessary. Just block off the sides so that cold wind cannot blow up under the screen, and into the hive.