Beekeeping Made Easy
Bottom Board and Entrance Reducer
Bottom boards serve a very useful function in a bee hive. It is the landing area and floor of the hive. When buying or building a bottom board, the beekeeper is faced with several choices. An entrance reducer is used during the winter to prevent mice and cold air from entering the hive. These are made of wood or metal. An entrance reducer design is included below following the design of the bottom board.
This has been the standard for years. Purchased bottom boards are going to be very much alike. They will have a shallow side and a deep side. The deep side has traditionally been used for winter with a entrance reducer installed at the entrance to keep out mice and cold windy air. 75 years ago a beekeeper would be expected to reverse the bottom board to the shallow side for summer and some bee books still teach that method. It was a good practice because the beekeeper would be cleaning the deep side of bees that dropped to the bottom board during the cold winter season and turn it down so the bottom summer side was up and gave the bees a very clean floor. Over time we have become a bit lazy and most beekeepers no longer flip the bottom board over. To clean the bottom board, these beekeepers either just let the bees do it or resort to a homemade cleaner such as a cloths hanger folded into the shape of a hook which reaches deep into the hive and the hook is then drawn forward, pulling out the debris and dead bees.
The screened bottom board has been around for several years. It was developed to allow varroa mites to drop thru the screen rather than land on the solid bottom and then crawl back up into the hive which they do. Those who have used them claim very good results with varroa mites. They are now being sold commercially but you could build one just as easily. It is important to remember that this type of bottom board has another working piece which completes it use. That is a sliding sheet of either metal or plywood which is used as a solid bottom during the winter to block drafts of air from reaching the bees. This is slid in to the bottom board in the fall and removed in the late spring. You can build a screen bottom board much like you would a regular bottom board with the exception that an opening must be cut into the bottom and covered with hardware cloth (not window screen wire).
You have more options if building your own bottom board. Many years ago, Dr. C.C. Miller advocated the use of deep bottoms with a slatted rack to help prevent swarming and over heating during hot summers. He described his bottom board as a plain box, two inches deep open at one end. Other comments he made: "With such a bottom board there is a space two inches deep under the bottom bars, a very nice thing in winter." "I leave the deep side up summer and winter." "I shove under the bottom bars a bottom rack. I value this bottom rack highly. It prevents building down and at the same times gives the bees nearly the full benefit of the deep space, preventing over heating in hot weather, thus serving as no small factor in the prevention of swarming. It also saves the labor of lifting the hive off the bottom board to reverse the bottom board and then lifting the hive back again, spring and fall." From Fifty Years Among the Bees.
Plans for building your own bottom board are shown below. This shows a bottom board that will look like a purchased bottom board. We would recommend that construction because if you want to resell your equipment, it will certainly be more desirable to prospective buyers.
