beekeeping equipment ventilation

Ventilation Part 4: The summer Langstroth hive

Here are some ideas for increasing summer ventilation in a Langstroth hive. They can be used singly or in combination, depending on your climate, weather patterns, hive strength, and personal preference.

  • The screened bottom board used for Varroa control is an excellent device for increasing ventilation in a hive. Many designs have a tray or drawer below the screen that closes off the air flow. Depending on conditions, the screened bottoms can be left fully open or they can be completely or partly closed.
  • In summer, the lower (main) entrance should be fully open in a strong and healthy hive. This not only allows for vast amounts of traffic but increases air flow as well. Weak colonies—especially those in areas prone to yellow jacket attacks—should have their entrances reduced to a size they can easily defend.
  • Upper entrances increase air circulation and often aid in reducing congestion. Many of the returning foragers will use an upper entrance if it is available. Upper entrances range in size from a tiny slot about ?-inch high by ¾-inch wide (1 x 2 cm) to the equivalent of a full main entrance. Full-size top entrances can be created by using three sides of an Imirie shim[1].
  • Short shims (not to be confused with Imirie shims) are small rectangular blocks about ¼-inch by ¾-inch by 2 inches (0.6 x 2 x 5 cm). A pair of these can be used between the topmost super and the telescoping cover to provide additional ventilation. The problem with these is that they create a very long opening that extends across the front and partway back on both sides—a configuration that is hard to defend from robbers and yellow jackets.
  • Holes are often drilled in one corner of the upper brood box. These holes are about an inch in diameter and usually screened from the inside. They provide a small amount of additional ventilation.
  • Ventilated inner covers can be used in place of regular inner covers. A ventilated inner cover is screened in the center and has end pieces that are higher than the side pieces. These end pieces hold the telescoping cover aloft so air can circulate through the sides.
  • Slatted racks also aid ventilation by reducing congestion below the brood nest and providing more space for air movement.
  • Feeders can be used with vented supers to reduce moisture build-up. Vented supers are just very shallow supers with holes drilled in each side. The holes are then screened from within.


Imirie shim with small entrance. Photo by the author.

Short shims. Photo by the author.

Ventilated cover shower higher end piece. Photo by the author.

[1] An Imirie shim is a rectangular frame the size of a Langstroth box and only ¾-inch high. By taking off one of the short sides, you have a u-shaped shim which can provide a full-size upper entrance.

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  • Rusty, what would happen if you turned the ventilated cover (your 3rd pic) upside down? Would it in effect create an upper entrance?

    • SDB,

      It would. Problem is, the entrance would extend all across the front and all across the back of the hive. I think that is too much entrance to defend except for the strongest of hives.

  • In my Langstroth hive, I poured hot beeswax, from a lit candle, to seal the parallel chinks of the redwood roof, along the length, where the two flat roofs join. Did I just block the tiny bit of ventilation possibility or is this nothing to be concerned about?

    • You don’t want rain to come in through the roof, so that part is good. But you still want upper ventilation, so if you don’t have any you should add some.

  • Do you use the inner cover AND the ventilated cover together? The inner cover goes on top of the super, then the ventilation cover goes OVER that – then the roof?

    • Vickie,

      Sometimes it’s the terminology that is most confusing. You should use one type of inner cover, either a standard one or a screened one. Then, over that, you need a roof—either a standard telescoping roof, a migratory roof, or a gabled roof. The decision has to be based on your local climate. For example, is cold the biggest problem, or moisture, or wind, or whatever? I’ve listed a number of options, but every location is slightly different.

  • Rusty,

    Since I’m now keeping honey bees in the south (not Pennsylvania anymore), and due to hive beetles and the varroa I now use screened bottom boards on all my hives. However, I came across a supplier that offered a beetle tray that slides in under the screen of the bottom board. The idea is that you put about 1/4″ of vegetable oil in the tray and the beetles and mites fall in and die. We’ve had a ton of rain here in South Carolina over the past three weeks and today we finally had a nice break in the weather and it gave me a chance to check on the hives.

    Everyone seems to be doing fine, but I discovered that my beetle trays were full to the brim with water and debris. I’m guessing these have been like this for a while, but was surprised to see how much water got in there. Needless to say, I believe this could lead to be a disastrous catalyst for moisture production for the colony (and we all know that’s no good). I didn’t see any mites in this oil/water mix, but I did see a ton of adult hive beetles dead in at least one of the trays. I also found tiny (1/8″) hive beetle larva in the pollen, wax, and other debris that was in that oil/water mixture…so I’m beginning to think the adult beetles are laying their eggs in the tray and the larva feed on the debris in it until they drown.

    I believe they all drowned because I found very few of the hundreds of larva alive. The colony is strong and I see no damage from hive beetles in the brood chambers, but I am a huge fan of beetle blasters and can tell you they are extremely effective in my hives. All that said, I’ve removed the beetle trays indefinitely for the time being. I don’t like the fact that so much rain water can get into them and I suspect it must be water that came in from the hive entrance. All of my entrances face east/south east to prevent them from facing into the prevailing winds/weather from the west as it usually the case here.

    • I use diatomaceous earth instead oil in Florida. DE kill all beetles and mites who run from hives to trays. To prevent water, I glued waterproof seal, like hard foam. I don’t like strips, because my bees cover them by propolis after 1 week. I also cover ground before hives by Landscape Weed Control Fabric from Home Depot.

  • Rusty,

    Sorry for bombarding you here, but I wanted this topic to be separate from the other. I’ve been having a hard time getting two colonies that I bought in 2x medium supers from drawing comb in a deep super above the brood chambers. I initially started out by placing the new deep super below the brood chambers, but no progress was made after two weeks, so now I’m supering on top and feeding 1:1 sugar syrup. After a week I still don’t see any progress on top of the black foundation, and I sprayed all of the foundation with the sugar syrup when I supered.

    I’m still feeding and am going to give it another week before I check for progress. The two medium brood chambers were completely drawn when I bought the hives, but I must say some of the frames were only partially drawn. My game plan is to get these two hives into deep brood chambers so I can eventually remove those medium brood chambers all together (especially since the foundation in them was drawn so terribly).

    Anyway, the question I have is do screened bottom-boards hinder the honey bees ability to draw comb? The reason I ask is because I thought the wax scales fall to the bottom-board where worker bees pick up the scales, chew, and move to the part of the hive where they need to draw comb. Using a screened bottom-board, these wax scales fall through the screen and are lost for good.

    If you don’t know, I have a little test in progress so I may have my answer in a couple days. I have two swarms that were installed this past week. One already has 8/10 frames drawn out, but they were installed in a hive that has a solid bottom-board. The other swarm was installed yesterday in a hive with a screened bottom-board. In a few days I’ll take a peek at the progress in that hive. I hope my hypothesis in false or I’ll be using solid bottom boards in all my hives that require foundation to be drawn out. Once the comb is drawn, then I’ll replace the solid with a screened bottom-board. I mentioned those beetle trays in my last post…those beetle trays were full of wax scales so I truly believe comb building is hindered to some degree. Thoughts?

    • Gerry,

      1. The bees have not drawn comb in the deep super because they are not ready. If virtually all the cells are full in the main nest, and if there is still honey to store, they will draw it out. Why store groceries in your out-buildings if you still have room in your kitchen? First year colonies very often do not store anything above the main nest area.

      2. I do not believe that screened bottom boards impede wax production in any way. In fact, good ventilation helps all aspects of honey bee health and productivity. What little wax is lost through the screen is more than made up for in colony health and comfort. Furthermore, according to articles I’ve read, the reforming of used wax is more apt to occur in the winter months when bees are not actively secreting it. As a general rule, spring and summer bees are not going to go around and pick that stuff up even if they could. Thousands of bees are producing more than enough.

      3. Two colonies does not an experiment make. You would need dozens or hundreds of repetitions to get statistically significant results that would actually tell you something.

      4. It all goes back to the bees and the fact that they don’t want to put comb where you want them to put it. It’s not that they can’t; it’s that they won’t.

    • Rusty,
      All points well taken…thanks for your input. Maybe I’m being a little too over-zealous for my bees. I’ll keep feeding and give them time… 🙂

  • I have read all the advantages of top entrances and want my bees to use the top one I have provided but they continue to use only the bottom one leaving only guard bees at the top one. How do I get them to use the top one? It just does not make sense to have the bees keep bringing in nectar and filling up the brood area so the queen has no place to lay.

    My hive is quite strong and the only one that made it through the winter so I do not want to risk losing it. It is quite tall with one deep and 7 mediums. I lost 8 hives over the winter so the supers, with some honey in each, went on this hive early in the spring. I started having back problems in January and had surgery 3 weeks ago. I wanted to give them lots of room to keep them from swarming and keep me from lifting until my back gets back to normal.

    They are doing a good job bring in white clover nectar and filling the supers from the bottom entrance only.

  • Sorry, I was not ready to send it. I have no idea why it went. I may have hit an enter at the wrong time. I was making some changes and the next thing I new it was sent. Sorry.

    So I will continue. It is a strong hive that I am pretty sure has not swarmed. I am worried that if I block the bottom entrance the bees will mass at the bottom and run the risk of overheating and killing them or the brood until they figure out how to use the top entrance. Can I just block the bottom entrance and they will figure out how to use the top one? Do you have any other suggestions?

    • Steve,

      An old saying tells us we can lead a horse to water but we can’t make it drink. Well, you can build top entrances till the cows come home, but if your bees don’t want to use it, they won’t.

      The top entrance is good for the hive even if they don’t use it. It increases air flow through the supers and thus aids cooling of the colony and drying of honey. Personally, I don’t see any point in forcing them to use it.

      You say it doesn’t make sense for them to fill the brood area with nectar and leave no room for the queen to lay. Well, it doesn’t make sense to us, but it does to them. If you close off the bottom entrance, they will still bring the nectar down and store it in the nest area if that is what they want. The workers regulate the size of the colony by opening cells in the nest area or filling them. Before swarming, for example, the bees begin to fill the brood nest with honey so the nest will be smaller after the swarm. Also, as winter approaches or during a nectar dearth, the workers may see fit to contract the brood area by filling it with honey.

      You can try opening the brood nest or pyramiding the brood nest to expand it, but each method would require lifting all those supers off the top. However, simply closing the bottom entrance won’t influence their decision on how big to make the nest.

      It sounds like the colony is strong and productive; I wouldn’t mess with a good thing.

  • Rusty,

    When using a screened-ventilated inner cover, how do the bees use the top entrance since the ventilated inner cover has no notch for the bees to enter and exit?

    • Hugh,

      Well, you can put one in. Some people use an Imirie shim with an entrance under the screened inner cover, and some drill a hole in the top corner of the upper brood box. Some put the Imirie shim between two brood boxes. Anything like that will work.

  • Hi Rusty, this will be my first summer to have bees and with our extremely hot July and August temps I want to give the bees the best chance possible to survive. I have left fresh water near so hopefully that helps. The hives have an OMF (tray removed) and an inner cover board with a hole in the middle placed above a shallow super that only has blank frames. The top outer cover has two vent holes at the sides. I have placed a large white styrofoam board (2inch thick) on top of the hive to provide shade and reflect some heat away from the hive. I am not expecting the bees to fill the top super with honey but as heat rises maybe this will aid the bees in keeping the brood box cooler for them. To add extra ventilation could I replace the inner cover with the queen excluder and place some fine mesh on top so the bees don’t go under the top cover. Would save me having to make a mesh inner cover. What would you advise? Thank you 🙂

    • Moya,

      What I would recommend is a mesh inner cover. But if that’s too much trouble, your way will work.

  • To: Gerry I live in the south also. I use the same screened bottom boards as you do with the oil trays. One, you have to check them weekly for build up wax debris. They will collect and start to draw wax moths to the wax in tray. They will also draw in shb that fall thru screen and drown in the oil. They do a great job of killing Varroa mites. Usually after a big rain go and empty tray in container and let settle then strain oil and reuse again. Do not give up on these they do a great job of keeping these 3 in check. I have them on most oh my hives. They have the least of problems, compared to solid bottom boards. Hope this may help.

  • Hello.

    I really enjoy reading all the Q and A. I am learning now before I get bees.

    My mentor uses a small 3 ” ventilation spacer above the inner cover so they can feed their bee’s using Ziploc bags with the slit cut into them.

    I would like to do the same except I really would like to have my hives a top entrance. But I’m worried about robbing.

    I live in Arkansas and it gets very hot here too.

    Would you recommend a screened inner cover to increase ventilation?

    • Greg,

      Yes, a screened inner cover would work to give you more ventilation. To increase the efficiency of the system, I would get rid of the inner cover and place the baggy feeders directly on the top bars surrounded by your 3-inch eke. And then put the screened inner cover above that.

  • Sorry for the second post.

    But what kind of top entrance is best to have in a southern climate? That doesn’t invite robbing? I’m not sure if I am making my point.

    I really don’t want to drill 1″ holes in my supers. But I feel using shims to tilt the cover and leaving all that space is just inviting a robbing situation.

    The reason I would like top entrance is my area is loaded with skunks and mice are a big problem too.

    And I really don’t want my hives so tall I have to use a ladder to super my hives.

    Any suggestions will be greatly accepted.

    • Greg,

      You can use an Imirie shim between any two boxes, although there is nothing better than the drilled one-inch hole. You can leave them open all year and plug them during robbing season. You get an entrance, ventilation, easy open and close, and they don’t invite burr comb the way the Imirie shim does.

  • Any information on the long hive would be appreciated. I use to have bee’s many years ago, before there was mite. I have a lot to learn. But wanted to get back into the hobby and the long hive would be my choice because I am 82 and cannot pick up full honey supers. Thanks in advance.

  • I live in southern Florida. I was just given a bee hive. I have read some books. lots of questions about ventilation in this hot and humid area. There are lots of opinions. Insulate roof section, sides, and screen bottom. Sometimes too much info is no help.

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