Rotating brood boxes, also called reversing, is a time-honored rite of spring. Beekeepers parade into their apiaries on the first warmish day and switch the position of their two brood boxes. They pry the boxes apart with a sharp crack and put the upper one where the lower one used to be, then place the other on top. Done deal.
It is important for new beekeepers to understand that rotating brood boxes refers to switching the relative position of the two boxes. Instead of #2 over #1, you have #1 over #2. It does not mean twisting them 180 degrees so the front is in the back and vice versa. What is obvious to experienced beekeepers can be incomprehensible to the uninitiated and, in many cases, the words don’t help.
The purpose of rotating brood boxes
The purpose of rotating brood boxes is to reduce the chance of swarming. Because it is quick and easy, it is a favorite maneuver of commercial beekeepers or those with many colonies to handle. In that case, it is probably somewhat effective at reducing the swarm impulse, at least for a while.
But for the backyard beekeeper with just a few hives to manage, it is more often than not an unnecessary disruption that can weaken a colony. And although it is quick and easy, other methods of swarm control are more effective.
Humans in control
As I see it, the worst problem with rotating brood boxes is that new beekeepers are taught it must be performed every spring. If you don’t tear apart your hive and move everything somewhere else, your colony is doomed to fail. After all, humans must intervene to keep their rightful place as center of the universe.
I admit that many years ago, I fell victim to this advice. The first thing I did in early spring was reverse all my brood boxes regardless of colony strength or the possibility of swarming. In other words, I was beekeeping by recipe instead of by logic, something that now riles me no end. If beekeepers would only stop thinking, no bees would die. Right?
These days, I see reversal as a tool—one of many at your disposal—to be used in certain circumstances depending on colony strength and need. After a beekeeper assesses a colony’s likelihood of swarming, he may choose to reverse the brood boxes or not. Instead of reversing, he may select a different method of swarm control or none at all. But he should not reverse brood boxes just because the calendar or a bee forum said so.
Which way do they go?
The mindless form of reversing brood boxes grew out of the misconception that bees only move in one direction inside a hive. All winter long we see the bee cluster moving up, not down. We begin to believe that they will only travel in one direction. No so.
Bees move up in a winter hive because that is where the heat is. Air that has been warmed by the bees’ bodies floats up, so the area above the cluster is the warmest place inside a hive or tree trunk or cave. Bees evolved to store their honey overhead and, most likely, this came about because those bees that stored honey in the warmest places were most likely to survive and pass their genes on to succeeding generations. Now it looks “standard” to us: bees store honey above the cluster.
By spring, the cluster is often as high as it can go, having eaten its way through the warmest food and often leaving colder patches of honey behind. We begin to think that bees only move up. But remember: that was winter.
Spring bees move down
It turns out that the natural direction for a colony to build new comb is down or out to the sides. Think about a feral colony. When a wild colony begins building, it starts at the top. It must. The first comb has to be attached to something overhead, so that is where it begins. Once that attachment is made, comb building proceeds down or out to the side.
In an open-air colony, the combs are often placed side-by-side along a tree limb. If the colony is in a narrow tree trunk or between the studs in a wall, the succeeding layers of comb are hung below the first ones. Down, down, down.
The bees in these colonies store their honey overhead for the most part, so that during the winter when they need to keep warm, the bees move up to where there is food and warmth. What a system.
If swarming is the problem
After a normal winter in the bee yard, your colonies have moved up through the food supply such that most of your remaining bees are in the top box. Due to increased brood production, the top box begins to get congested. Congestion inspires swarming. So voila! You just rotate brood boxes and your problem is solved. Or is it?
After you reverse your boxes, the queen may move up to the top box and begin nesting there. On the other hand, she may not. Instead of a congested box above an empty box, you simply have an empty box above a congested box. Rather than moving up, your bees may decide to swarm regardless of the extra space.
If you are worried about swarming, I find it best to spread the frames vertically rather than simply reversing brood boxes. A vertical spread, often called pyramiding, means you take the brood frames and put them in the center of two brood boxes, one atop the other. With drawn comb on either side of the brood, the queen has plenty of space to lay eggs. This is more work than simply reversing, but the results are usually better.
No signs of swarming
If swarming does not seem imminent, you can simply leave the brood boxes in place and add honey supers at the appropriate time. As the season progresses, the bees will store honey overhead and the queen will gradually expand the nest down into the empty bottom box. They would do this in a tree and they will do it in your brood box. If later you begin to see signs of swarming, such as backfilling the brood nest, then you can take other measures to control it.
If you decide to proactively reverse brood boxes, remember that a colony spanning both boxes will be split into two parts when you reverse. Without enough nurse bees to go around, you risk losing one or both halves in a cold snap. In short, reversing too early can be deadly for your colony.
But if you wait too long, swarm preparations may already have begun. If that happens, they will most likely swarm anyway, making the reversal pointless.
Case by case
In summary, I believe it is important to handle rotating brood boxes on a case-by-case basis. Understand why you are doing it and what you are trying to achieve. Remember that rotating is a choice to be made, not a mindless exercise to be performed just because it’s spring.
Honey Bee Suite