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Hive five: equipment to improve summer ventilation

Summer is coming to a close even though it was nearly a “non-summer” here on the Pacific Northwest coast. The corn hasn’t tasseled; the peaches look like walnuts. Nevertheless, my bees are healthy and I had a good honey harvest–much better than expected. My honey was capped and my hives are dry inside. What more could I ask for?

This is just a quick review of ventilation equipment I used this year. Although there are others, these are my favorite five.

Screened bottom board: In my opinion, this is a must-have piece of equipment. Whether or not it effectively controls mites is anybody’s guess, but it is great for ventilation. It allows large volumes of air to enter the hive while keeping out mice, large insects, wasps, and other bees.

Screened inner cover: In order for air to move through the hive, it needs a place to go. The screened inner cover is my favorite choice for reasons similar to the the screened bottom board. It allows plenty of air movement but blocks entry to predators. Before I began using them, the tops of my section boxes frequently became stained with mildew because moisture got trapped beneath the inner cover. Now that problem is completely gone.

Ventilation eke: I used ventilation ekes on a few hives where I was short of screened inner covers. These worked almost as well and would have worked even better with more holes. The ones I used had four holes, two on each of the long sides. In the future I will add at least one hole–and maybe two–on each of the short sides as well. The ventilation eke is an economical solution because I can staple canvas to the bottom and use them as moisture quilts in the winter.

Slatted rack: The slatted rack improves ventilation because it gives the bees a place to congregate inside the hive. This allows better air flow through the hive because the bees are not filling up the bee space between the frames. On hot days the bees hang in beards from the slats instead of jamming up the front entrance. It is especially effective when used with a screened bottom board.

Follower boards: Like the slatted rack, follower boards give the bees a place to congregate inside the hive. Unlike the slatted rack, the follower boards are at the sides of the hive. In my hives with follower boards, the bees used more vertical space for the brood nest. (Since the bees have only eight instead of ten combs per box, they expand into an upper box sooner.) This tall and slender hive structure is more tree-shaped and seems to provide a “chimney effect” that pulls the air through the hive. My hives with follower boards did especially well with honey production.

My next experiment will center on a gabled roof with ventilation ports at each end. I’m going to start with a prototype from a reader in Maryland who has had excellent success with his design. I will be using it for both summer and winter moisture management and writing about the results. Stay tuned for more about the ventilated gabled roof.


What size hardware cloth is best for bee hives?

If you are building or repairing your own bee “furniture” you will find there are many sizes of hardware cloth available. Usually, the ones you need are the hardest to find.

Here in the States, hardware cloth is numbered according to how many squares fit in a linear inch. So #5 has five squares to the inch and #8 has eight squares to the inch. In other words, a bigger number means a smaller hole.

Here are some examples of how the different sizes are used:

Some of the bee supply companies sell hardware cloth by the foot or the roll, and it is also available online from a number of sources. I buy it from The #8 size is listed as 1/8” x 36” x 10’, which may look confusing, but they just list the mesh size as the first dimension followed by the width and length.

It is difficult to make hard and fast rules about the right size of hardware cloth to use because some bees—depending on genetics and cell size—are larger than others. Also, the thickness of the wire varies from one manufacturer to the next, and a thicker wire means a smaller hole.

The above guidelines work pretty well. If you have problems you can experiment with the sizes until you find the combination that works best with your bees.


*This post contains an affiliate link.

Measuring the bone pile: death in the hive

Yesterday I pulled the screened bottom board out of my top bar hive and dumped it. What seemed like an incredible number of moldy bees mixed with pollen and comb dropped heavily to the ground. It made a wet thud, like a saturated mop hitting the deck.

Cleaning the unappetizing stew of deadlings off the bottom board is a rite of spring. Although it can be disconcerting to a new beekeeper, it is nothing to be alarmed over. Here’s why:

An average colony going into winter may contain 50,000 bees. An average overwintered colony stirring in spring may contain 20,000 bees. So where are the other 30,000? Well, a goodly number of them are in that pile; others were carted out of the hive by ambitious house bees during the winter months. You saw those on the landing board and in front of the hive in the snow.

If the hive appears healthy and active then the pile of dead bees is just—well—a pile of dead bees. Clean it up, put the hive back together, and forget about it. Everything is going according to plan.


Bees benefit from an energy conservation professional

Late on the second evening of the recent cold snap I checked the outside temperature. It was 15° F, and I was very glad I had taken the nucs into the garden shed where it was about 44°. My husband asked me if the nucs had enough ventilation, and I said, yes, each nuc had a screened bottom.

At that point he became concerned about too much ventilation, to which I replied that all the other hives—meaning all those still out in the real cold—had screened bottoms with no Varroa drawers beneath. He went ballistic.

Now, I know I had explained all this to him before but, like most men, he doesn’t listen unless I’m talking about the next meal. So I explained it all again.

I’ve talked to many beekeepers who are taking the Varroa drawers out in order to increase wintertime ventilation. Since heat rises, it doesn’t drop out the bottom—and the real heat in a hive is in the center of the cluster. Many beekeepers believe the air temperature in the space surrounding the cluster is very close to the ambient outside temperature. In other words, the hive itself is providing very little insulation. It is, after all, just a plain wooden box.

My husband argued that this was close to true—but not entirely true. He said that the few degrees of difference would have a large impact on how hard the bees had to work to keep warm—and how much fuel they had to consume to do it. He said I should replace the drawers immediately. Grudgingly, I agreed. (Okay, he is an engineer and a specialist in energy conservation, but that didn’t make the whole thing any less irritating.)

It just so happened that this conversation was taking place at 11:30 p.m. Nevertheless, we collected flashlights, boots, coats, gloves, and a stack of Varroa drawers and went trekking up that blasted hill in the middle of the night. It was snowing, blowing, and freezing. Large branches and small trees had fallen across the path, and I was muttering about them—and about men—the entire time.

We slid the drawers in place at each hive. I noticed that the lower entrances were all covered with snow such that you couldn’t even see where they were, but I decided that I would wait and clear them in the morning. For the moment, I just wanted to be done.

Now, here’s the rub. When I climbed the hill the next morning the temperature was still in the teens and the snow was even deeper. But much to my amazement, during the night the snow had melted around each of the entrance holes. So not only had the temperature gone up inside the hives, but it had climbed above the freezing point—otherwise the snow would not have melted at the opening.

In the end, the bees benefited from this little exercise, my husband is feeling smug, and I am still annoyed. Still, though, I have a new problem to solve. Perhaps I will drill holes in the Varroa drawers so they let in some air—just not all the air. I modified my top-bar hive that way last year and it works great. I’ll let you know what I decide.


Ventilation in a hot & humid climate

Yesterday a reader from Florida asked for specific instructions on how to keep a hive well ventilated in a hot and humid climate. This is a good question. Although colonies can usually survive hot and humid conditions, they will produce more honey and be less stressed if they don’t have to spend all their energy cooling the hive. Here are some suggestions:

  • Keep the hive up off the ground. By placing the hive on a stand, you allow air to circulate on all sides—including the bottom.
  • Use a screened bottom board without the Varroa tray. A screened bottom allows air to circulate into the hive from underneath, and it has a much larger surface area than a standard entrance.
  • Use an upper entrance. An upper entrance, either drilled in the top hive body or cut into an inner cover, allows the hive to behave much like a chimney. Air will come into the hive from the bottom entrance or screened bottom and exit through the upper entrance.
  • Even better than an upper entrance is a ventilated inner cover. 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. The screening should be small enough to keep out robbing bees. (see photo below)
  • Keep your hive in the shade. Left to their own devices, bees will usually select shaded areas in which to live. A little morning sun is fine, but a shady location will allow the bees to spend their afternoons foraging instead of fanning.
  • Hives in hot locations should be painted light colors and have a white or metallic roof.
  • Place a slatted rack under the bottom brood box. Slatted racks can aid ventilation by reducing congestion below the brood nest and providing more space for air movement.
  • Do not allow your hive to become too crowded. If the bees need more space give them an extra brood box.
  • Make sure your bees have a source of clean drinking water.


Ventilated inner cover--end pieces are shimmed to provide maximum air movement.