As you get into beekeeping, you will find that there is more equipment needed as you become more advanced in your beekeeping. A double screen board is a beekeeping tool that has several uses for the beekeeper to perform various actions on the colony.
A double screen board or Snelgrove board is a baseboard separating two chambers in a beehive with a double mesh layer to prevent contact between the bees. The purpose of the board is to share heat between the chambers for the purpose of overwintering small colonies or splitting colonies.
Double screen boards for beekeeping can have various designs and can be used to overwinter nuc hives, prevent swarming, and for splitting a colony to increase the number of colonies in your apiary. How do you use double screen boards, and do they work for beekeepers?
What Is A Double Screen Board For Beekeeping?
A double screen board is a tool used by beekeepers to perform various beekeeping tasks on colonies. A double screen board is also known as a Snelgrove board.
The double screen board is typically used with Langstroth bee hives and is the same length and width of the hive and is about 1-inch or 25mm deep.
The floor of the double screen board is usually a single piece of wood or plywood about ¾ inch or 20mm thick. The board has a hole cut in the middle to “join” upper and lower boxes together and a double screen over the hole to prevent the bees from touching each other.
The hole in the double screen board will have mesh over both sides of the hole, the top, and the bottom. This hole and mesh configuration allows air to pass through the board but does not allow the bees from the box above and below to physically contact each other.
A double screen board can be made easily at home by creating a board with the correct dimensions to fit the hive, cutting a hole in the board near the middle and coveing both sides of the hole with 1/8 inch hardware cloth or mesh.
How Does A Double Screen For Beekeeping Work?
The double screen board is placed between the bee box above and the bee box below, allowing air transfer between the two boxes, but no contact between the bees.
Pheremones In the hive are transported by contact between bees rather than being airborne in the hive. The double screen on the board allows two groups of bees to share the same space without causing fighting between the bees due to different queen pheromones or fighting between the queens.
So how would you use the screen board in practical beekeeping situations? We will discuss the main uses of the double screen board and the ways most beekeepers use these devices.
Double Screen Board For OverWintering A Nuc Colony
Double screen boards come with various hole placements, depending on how the board is used. A board used to over winter a nuc or nucleus hive usually has two holes in the board; one on the left and one on the right.
This allows two 5-frame nuc hives to be positioned on top of the board. The nuc hives would not have a baseboard of their own, as the double screen board will act as the baseboard.
The holes in the double screen board allow warm air to flow from the strong hive below into the nuc hives with the weaker colonies. This helps to keep the nucs warmer during winter, and the smaller colony does not have to work as hard to maintain optimal hive temperatures.
Sharing the warmth of the strong colony below helps the nuc colony to use fewer resources for the winter and requires less energy from the lesser number of bees.
The double screen allows the warm air to pass through into the nuc but prevents direct contact between the bees, preventing fighting and spreading of pheromones from the strong hive to the nucleus hives above.
The opposite side to the entrance double screen board will have an opening for the nuc bees to exit and enter the nuc hive on the of the larger hive below. This difference in entrance position will prevent the bees from becoming confused and entering the wrong hive.
Another option to overwinter a single nuc is to use a double screen board with a single hole and place a full-size brood box on top and transfer the 5 frames of bees from the nuc to the full size box. Place them in the middle of the box and place empty frames on either side with wax foundations sheets.
Double Screen Board To Prevent Swarming
Bees typically swarm when the hive is becoming too small for the number of bees in the colony. When the colony swarms, the beekeeper loses a large portion of their bees.
If you notice a strong colony beginning to build swarm cells (queen cells), you can prevent swarming and losing part of the colony by using a double screen board to split the colony.
Once the bees have begun to build swarm cells, it is practically impossible to prevent them from swarming. However, splitting the colony with the double screen board will allow you to keep the bees and increase the number of active colonies.
When you notice the swarm cells in the hive, you can remove the frames with the swarm cells, place a snelgrove board on top of the original hive, place a new brood box on top of that and place the swarm cells in the new brood box.
When a queen hatches from one of the swarm cells, she will kill the other queens, but she will not be able to get to the original queen in the brood box below. Essentially, the new queen will have a colony ready to be productive and there is no reason to swarms.
She will stay in the top brood box, and once established, you can remove the top brood box, give it a standard baseboard and place it in a new location.
You would have effectively split the colony to prevent swarming and losing any of your bees.
Double Screen Board To Split Bee Colonies
A Snelgrove board, or double screen board, can be used to intentionally split a colony, even if there are no swarm cells in the hive.
A new brood box can be placed on top of the original brood box, with a snelgrove board separating the two and with the entrance on the opposite side to the bottom box.
Frames of capped brood and frames with eggs can be moved to the top brood box. The empty space in both brood boxes can be filled with empty frames with wax foundation.
The frames must be moved with the nurse bees still on the frame. Any adult workers on the frames moved to the top box will exit the hive and go back to the entrance of the lower hive.
Any new brood that hatch in the top box will use the entrance on the top box and will return to this entrance rather than using the entrance on the lower box.
You can introduce a new, mated queen to the top brood box after a few days, or you can wait for the nurse bees to realise there is no queen, and they will raise a new queen for the colony from one of the eggs.
You may need to give the top box a new frame with fresh eggs once the boxes have been separated for 3 days. This will give the top box new eggs to ensure a queen can be raised.
The benefit of the snelgrove board in this case is to provide heat from the bottom hive to help heat the top box and keep the brood viable until a new queen can be raised.
A double screen board or snelgrove board can be used for a variety of beekeeping functions. The most common uses are to overwinter a weaker colony from nuc hive, prevent swarming in a strong colony, or intentionally splitting a colony.
Double screen boards are easy to make if you have some basic DIY skills and will be a useful tool as your beekeeping skills advance.
Writer’s own experience.