Updated on September 11th, 2022
In a Langstroth hive, a honey bee colony’s explosive population growth in the spring leaves little room for honey in the brood boxes. The queen keeps brood in middle frames while honey is limited to some outer frames.
When nectar is abundant, bees need additional space for honey production and storage. Thus, beekeepers add hive bodies with drawn comb above the brood nest as “honey supers.” Preferring that supers contain only honey and not brood, many beekeepers restrict the queen’s access to supers using a queen excluder.
A queen excluder is a metal or plastic grill serving as a selective barrier between hive boxes. Gaps in the grill permit passage of worker bees but not the larger queen and drones. An excluder placed above the brood nest prevents the queen from accessing the honey supers to lay eggs.
Beekeepers differ in their opinions about whether to use queen excluders. Views vary based on individual experiences and observations. (Maybe it is bee colonies that have different ideas.)
This article discusses what is a queen excluder in detail to help you decide if they are suitable for your colonies.
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What Is A Queen Excluder?
Plain and simple, a queen excluder is a grill with openings 0.163 – 0.172 inches (4.14 – 4.37 mm) wide. These openings are large enough for worker bees to pass through. However, queens and drones, which are much larger than workers, cannot pass.
Keeping Brood Out Of Honey Supers
A queen excluder’s function is to keep the queen from laying eggs in honey supers for several reasons:
- Mixing brood with honey is unsanitary and would ruin the harvested honey. Therefore, without the risk of brood in the honey supers, beekeepers freely remove supers for honey extraction.
- Removing bees from supers makes extraction easier. However, nurse bees can be reluctant to leave brood.
- Bees may store pollen (bee bread) around brood for feeding purposes. Therefore, keeping brood out of the supers also keeps out excess pollen.
Plastic Queen Excluder vs. Metal Queen Excluder
Queen excluders come in three primary forms:
- Molded plastic,
- Wood bound (i.e., framed) metal, and
Molded plastic queen excluders is preferable to stamped plastic ones. Stamped plastic tends to have rough edges that can damage bees when passing through.
Metal queen excluders are bound either with wood or metal framing. Wood framing is thicker, creating bee space and making the excluder more visible to the beekeeper.
Queen Excluder Comparisons
|Info||Plastic||All Metal||Wood Bound Metal|
|Material||Molded plastic (avoid stamped plastic)||Galvanized steel||Galvanized steel/wood frame|
|Bees may||Propolize openings||Propolize openings||Add burr comb|
|Visibility to beekeeper||Low||Low||High|
|Cleaning||Freeze and flex to remove propolis or scrape with a plastic tool; avoid heating||Scrape with a tool||Scrape with a tool|
|Life span||Shortest; may sag or warp; susceptible to sun and heat damage; may be damaged by tools||Longest||Long life of grill; wood frame susceptible to damage|
Queen excluder dimensions fit either 10-frame or 8-frame Langstroth hives.
See our article on why we think the Langstroth hive is the best beehive for beginning beekeepers.
Where Do You Put A Queen Excluder?
Put a queen excluder above the upper-most brood box and under the first honey super that you plan to harvest. A metal excluder’s crossbars face down toward the brood nest.
Some beekeepers place a queen excluder beneath the brood box for a few days after installing a new bee package. The purpose of this placement is to discourage absconding. However, do not leave an excluder in this location for long as it keeps drones from exiting the hive as needed.
Queen Excluder And Swarming
Swarming is a natural occurrence by which bees form a new colony and expand their population.
When bees swarm, a queen leaves a hive taking about half the colony with her. Before swarming, the bees begin the process of raising a replacement queen for the bees that remain.
Our article about swarm traps had more information about swarming.
Using A Queen Excluder To Prevent Swarming (Only Temporarily!)
Placing an excluder under the brood and above the bottom board can temporarily prevent a colony from swarming while you take other preventive measures like splitting the hive.
However, a bottom excluder is not a long-term swarm prevention tool. In addition to blocking the queen, a bottom excluder prevents drones from exiting the hive, so do not leave it in place for long.
If the queen is blocked from swarming, the colony may wait for a virgin queen to emerge. This new queen may be small enough to breach the excluder and leave with the swarm.
All you can hope to do with a bottom excluder is delay swarming.
Note: If you want to delay swarming briefly, try using an entrance guard like this one available at Blythewood Bee Co. Placing a sward guard in front of the entrance is much easier than removing boxes to put a queen excluder on the bottom board. A swarm guard is a mini queen excluder.
Do Queen Excluders Cause Swarming?
Some beekeepers believe that queen excluders cause colonies to swarm by creating the perception of limited space. However, I am not aware of any scientific studies that determine this to be a fact.
A queen excluder may sometimes contribute to swarming, and other times it plays no role.
If honey supers and queen excluders are added after the colony has determined it will swarm, there may appear to be a cause and effect that does not exist.
Do Queen Excluders Harm Bees?
A properly constructed excluder without sharp edges will not harm worker bees. However, drones that attempt to squeeze through may get stuck and die.
To limit possible damage to drone bees, do not leave an excluder on the bottom of the hive for an extended period. Also, provide an upper entrance to accommodate any drones that find themselves trapped above an excluder for some reason.
Will Bees Build Comb Above A Queen Excluder?
If you place drawn comb in the first honey super above and excluder, bees will fill it. However, if the frames have bare foundation, the bees may be reluctant or slow to draw comb.
Once the first super is well underway, bees will draw comb on bare foundation (or foundationless frames) in subsequent supers.
However, if the frames have just foundation, the bees may be reluctant to draw comb.
Do You Really Need A Queen Excluder?
You do not need to use a queen excluder if you are managing colonies with multiple brood boxes. However, a queen excluder is required if you want to manage only a single brood box.
Here’s a video that explains single brood box management:
Many beekeepers eschew them as “honey excluders” that reduce a hive’s production. Without an excluder, the queen is free to roam wherever she wants, just like in a natural hive.
If you are a hardcore believer in treatment-free beekeeping, then a queen excluder would probably be considered a form of hive manipulation and avoided.
Queen Excluder Pros And Cons
Queen excluder advantages and disadvantages can be either real or perceived.
Advantages of queen excluders include:
- Locating the queen is easier if her ability to roam the hive is restricted.
- Honey supers are removed efficiently without the need to check for brood or bee bread cells.
- Limiting brood area for the queen controls the population, which may result in fewer varroa mites and a less defensive colony.
Disadvantages Of Queen Excluders include:
- Plastic excluders can be damaged and fail.
- Excluders are an added cost and an item that requires storage when not in use.
- Excluders may artificially limit the population size that a prolific queen could create. A larger population may mean more honey.
- Drone bees may be damaged attempting to squeeze through an excluder.
- Many beekeepers feel that excluders reduce honey production by hindering the easy movement of bees, especially if burr comb or propolis blocks the excluder.
Queen Excluder Tips
As an alternative to a queen excluder:
- If you have frames with honey, place them in the first honey super. A queen is unlikely to pass this “honey barrier” and move up in the hive, or
- Use an excluder only until the first super is filled out to create the barrier.
- Try to keep the queen as low as possible by rotating brood boxes.
Add an upper entrance so foragers can bypass any queen excluder. We drill openings in some supers that provide access and help ventilate the hive. Add inexpensive entrance gates like these on Amazon to close the opening quickly if robbing occurs.
We recommend that first-year beekeepers not harvest any honey. If you follow our recommendation, then skip the excluder and let the queen do as she wishes.
Our Experience With Queen Excluders
We used a queen excluder the first year we planned to harvest honey. After that, it seemed to take forever for the bees to move up into the super.
They were probably slow to move up because we had bare foundation in the super. Or maybe they just weren’t ready.
Whatever the reason, we opted to skip the excluder after that. Only once did a queen venture up and lay eggs in the bottom super.
Unless you are managing single brood boxes, queen excluders are an optional tool that has certain advantages.
We suggest you experiment with and without excluders and form your own opinion as to their usefulness.
 The Reasons Why the Queen Excluder Limits Honey Production by Walt Wright, Beesource, Bee Culture