Beehive Entrance Reducer: What It Does, When to Use It and When to Remove It
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A beehive entrance reducer is a notched strip of wood or metal that sits in the hive entrance and shrinks it to a small gap. A smaller door is easier for the guard bees to defend, so a reducer helps new or weak colonies fight off robbers and wasps and hold their heat in cold weather. You use it on new colonies, during a nectar dearth and over winter, and take it out once the colony is strong and the nectar is flowing.
This guide explains how a reducer works, which opening to use and when, the signs it is time to remove it, and how wooden and metal reducers compare.
What an entrance reducer is
On a standard Langstroth hive, the bottom board leaves a slot about 3/4 inch high running the full width of the hive. That is roughly 14 3/4 inches of doorway on a 10-frame hive and about 12 1/4 inches on an 8-frame. A strong colony of 40,000 or more bees has no trouble guarding that. A package or a five-frame nuc of a few thousand bees does.
The classic reducer is a piece of wood about 3/4 inch square, cut to the width of the entrance, so it fills the slot completely. Notches cut into two of its faces make the openings. Turn the strip to choose which notch faces the bees.
The two openings
Sizes vary a little between makers, but most wooden Langstroth reducers look like this:
| Setting | Typical size | Use it for |
|---|---|---|
| Small notch | About 3/8 inch high and 3/4 to 1 inch wide | Newly installed packages, small nucs, active robbing, deep winter |
| Large notch | About 3/8 inch high and 3 to 4 inches wide | Growing colonies, cool spring weather, dearth periods for mid-strength colonies |
| No reducer | Full width, about 3/4 inch high | Strong colonies during a nectar flow and in hot weather |
The 3/8-inch height is deliberate. It is the classic “bee space”, enough for bees to pass freely, and small enough to keep out larger pests. It will not reliably stop mice, though, which is why many beekeepers add a separate mouse guard in fall (more on that below).
When to use an entrance reducer
New packages and nucs
Fit the reducer on day one when you install a package or a nuc. The colony is small, it has no stores to speak of, and it is often being fed sugar syrup, which draws robbers. Start with the small opening for a package and the small or large opening for a nuc, depending on its strength. Our guide to obtaining and installing a nucleus colony walks through the first weeks.
Robbing and nectar dearth
When flowers dry up in late summer, foragers from strong hives go looking for honey they can steal. A weak colony with a wide entrance can be stripped in a day or two. Signs of robbing include fighting at the entrance, bees darting and weaving in front of the hive rather than flying straight in, and bits of wax cappings on the landing board. Drop to the small opening straight away. See robber bees and how to stop them for more steps. A reduced entrance also helps against yellow jackets, which peak at the same time of year.
Winter and cold snaps
A narrower entrance cuts cold drafts across the bottom of the hive and gives the winter cluster less doorway to guard. Most beekeepers in cold climates fit the reducer, or a metal mouse guard, as part of their fall routine. Do not seal the hive completely, though. Bees need to take cleansing flights on warm days, and moist air needs a way out. Our winter hive preparation guide covers upper ventilation and moisture.
How to fit or change a reducer
- Pick your moment. Early morning, evening or a cool, cloudy spell means fewer foragers at the door. A puff of smoke at the entrance moves the guards back.
- Slide it in firmly. The strip should fill the slot from side to side with no gaps at the ends, or bees and robbers will simply use the gaps.
- Keep the landing clear. Scrape away dead bees and debris in front of the notch so bees can walk straight in.
- Watch for ten minutes. Returning foragers will cluster briefly while they find the new door, then settle. If they are still piling up after an hour, switch to the larger opening.
When to remove the reducer
A reducer left in too long causes its own problems. Take it out, or move to the larger opening, when you see these signs:
- Traffic jams. Foragers queue on the landing board waiting to get in, especially in late morning and afternoon.
- A strong nectar flow. Once the colony covers most of its frames and flowers are in full bloom, every minute a forager waits at the door is lost nectar.
- Hot weather. Bees fan air through the entrance to cool the hive and dry nectar. A small entrance makes that much harder, and heavy bearding on the front of the hive can be a sign they are struggling. Our guide to hot hives in summer has more.
- Dead bees piling up. In winter, dead bees can block a small notch. Check the entrance after cold spells and clear it with a stick or hive tool.
Many beekeepers remove the reducer entirely by late spring and put it back when the summer dearth starts. Keep it in a shed or tuck it under the outer cover so it is handy.
Wooden vs metal entrance reducers
| Wooden strip | Metal (sliding or disc) | |
|---|---|---|
| How it fits | Pushed into the entrance slot | Screwed or pinned to the front of the hive |
| Openings | Two fixed notch sizes, or closed | Sliding plates or rotating discs give several settings |
| Mice | Mice can chew wood and enlarge the gap | Stainless steel cannot be chewed; many double as mouse guards |
| Weather | Can swell or warp if left bare | Does not swell |
| Fit | Must match the hive width (8- or 10-frame) | Adjustable types cover several hive sizes |
| Best for | Simple, cheap reduction on standard hives | Year-round use and winter mouse protection |
A wooden reducer is the one most beginners get in their hive starter kit, and it does the job. If mice are a problem where you live, a stainless sliding guard that works as both a reducer and a mouse guard is worth adding; see our guide to beehive mouse guards.
Check the bottom board first
A strip reducer depends on the entrance slot being the standard height. Some screened bottom boards, migratory bottoms and imported hives have a different entrance, so measure yours before you buy.
Our entrance reducer picks
1. Wooden 10-Frame Entrance Reducer, 4-Pack (best value for several hives)
This is the classic wooden strip reducer, sold as a pack of four, so one order covers several hives or gives you spares for nucs you later move up. Each strip measures 14.75 x 0.75 x 0.75 inches, the size to fill the entrance of a standard 10-frame hive, and the listing says it fits solid-bottom hives. Turn it to choose the small or large notch, and store the spares under the outer cover so one is always to hand when robbing starts.
- Good: Four reducers in one pack; standard 10-frame size
- Watch for: Listed for solid-bottom hives, so check the fit on a screened bottom board
2. BeeCastle Beeswaxed Cedar 10-Frame Entrance Reducer (best single reducer for 10-frame hives)
BeeCastle makes this reducer from cedar and coats it in beeswax, the same finish it uses on its hive boxes, so it suits a beeswaxed cedar hive if you already run one. It is 14.60 inches long for a 10-frame Langstroth entrance. As with any strip reducer, push it in snugly so there are no gaps at the ends, start new colonies on the small opening, and move to the larger one as traffic builds.
- Good: Cedar with a beeswax coating; matches BeeCastle hives
- Watch for: Sold singly; wood can still be chewed by mice, so pair with a metal guard in winter
3. BeeCastle 8-Frame Entrance Reducer (best for 8-frame hives)
Eight-frame hives have a narrower entrance, and a 10-frame reducer simply will not fit. This BeeCastle reducer is made for 8-frame Langstroth hives and measures 12.20 inches long. It is the easy choice if you run 8-frame equipment, which many beekeepers prefer because the boxes are lighter to lift. Measure your entrance first, since 8-frame hives from different makers can vary slightly in width.
- Good: Sized specifically for 8-frame Langstroth hives
- Watch for: Check your entrance width before buying; will not fit 10-frame hives
Frequently asked questions
Should the entrance reducer notch face up or down?
Most beekeepers put the notch down, against the bottom board, so the bees walk straight in at floor level and can drag debris out. Some turn it up in winter so dead bees on the floor do not block the gap. Either works; just check the entrance stays clear.
How long should I leave the entrance reducer on a new hive?
Usually until the colony is covering most of the frames in its box and you see congestion at the entrance, often three to six weeks for a package or nuc in spring. Move from the small opening to the large one first, then remove it.
Do I need an entrance reducer in summer?
A strong colony usually does not, and the extra airflow helps it stay cool. Weak colonies, and any colony during a late-summer dearth when robbing starts, benefit from having the reducer back in.
Does an entrance reducer keep mice out?
Not reliably. Young mice can squeeze through very small gaps and can chew a wooden notch wider. Use a metal mouse guard with bee-sized holes from fall through early spring.
Can I make my own entrance reducer?
Yes. A strip of 3/4-inch square wood cut to the entrance width, with a small and a large notch about 3/8 inch deep, works fine. Round off the notch edges so they do not splinter, and give the wood a coat of beeswax or leave it bare.
An entrance reducer is one of the cheapest pieces of kit in the apiary, and used at the right times it can save a young colony. For more on day-to-day hive management, browse our bee care guides.
