Reversing brood boxes: when and why
Your colony has made it through the winter, and the first warm day of spring is turning the earth green. The bees are packing in pollen and all seems right with the world. Sure enough, it’s time to reverse your brood boxes.
Reversing boxes simply means you take the upper brood box and place it below the other one. Over the course of the winter, a bee cluster moves upward. Honey is usually stored above the brood nest and, as these stores are used, the entire cluster migrates in that direction. Reversing puts the bulk of the cluster in the bottom of the hive again, thus providing room above to store honey. Since the bees now have a place for their supplies, reversing tends to delay swarming. In some cases it may prevent swarming.
Here are some guidelines:
- Choose a warm day in early spring. Temperatures above 60°F (16°C) are good for this.
- Remove covers and feeders. When you get to the upper brood box, clean the tops of the frames of burr comb. Pry the box loose, and set it on end.
- Now clean the burr comb from the tops of the frames in the lower brood box. Pry loose, and set it on end as well.
- Now is your opportunity to clean your slatted rack,Varroa screens, bottom boards or whatever you have down at the bottom of the hive.
- Now go back and scrape the burr comb from the bottoms of the frames in both brood boxes. This is easy with the boxes set on end. Removing the burr comb is important so you don’t smash bees when you reassemble.
- Now reassemble the hive, putting the brood boxes in opposite positions.
Some additional considerations:
- If you imagine the cluster as a sphere spanning both boxes, you will see that reversing causes the cluster to be broken into two parts. One part (the largest part, we hope) ends up in the lower portion of the lower box. The other (smaller) part ends up in the upper part of the upper box. If you reverse too early in the year, there won’t be enough bees to keep both parts warm. This is where good judgment—and good luck—comes into play.
- If you wait too late in the spring, swarm preparations may already be underway, and you lose the benefits of reversing.
- If you find your winter cluster is very small and easily fits in one box, you may want to remove the empty box until the hive regains strength and numbers. In the meantime, you have an opportunity to maintain that box, re-paint it, clean frames, replace frames or do whatever needs to be done.