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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.

Rusty
HoneyBeeSuite

Summer ventilation increases honey yield

Whenever I think of summer ventilation, I think of the White House beehive. Beekeeper Charlie Brandt uses a large eke with a hole cut in each side. The eke is mounted above the stack of honey supers, just below the telescoping cover. The holes are large—I estimate about three inches in diameter—and are screened on the inside. On the outside, the holes are protected from lawn sprinklers by clear plastic splash guards. The splash guards are mounted several inches from each opening to minimize interference with the air flow.

My preference for top ventilation in summer is a screened inner cover with shims on each end. The shims keep the telescoping cover elevated so the air flow is not blocked. The screened inner covers keep even my busiest hives dry during the summer and they keep out insect predators as well. Since the bees have an easier time dehydrating their nectar, a well-ventilated colony can cure more honey faster.

I don’t have enough screens for all my hives, but a reader gave me the idea of turning a moisture quilt upside down and using it in place of an inner cover. My moisture quilts have holes on only two sides, but this system works fairly well. It’s not quite as good as the screened inner cover, but it is certainly better than nothing.

Before I had either screens or quilt boxes, I shimmed the outer covers on the front side of the hive with two pieces of wood about a half-inch high–another technique that keeps the hive well-ventilated. In addition, the bees use it as an upper entrance which lowers congestion at the main entrance. The downside of shims is that both robbers and yellow jackets can also use the opening. So while shims work fine during a nectar flow, they must be removed during a dearth when robbers and wasps are more of a problem.

An enormous amount of bee energy is wasted when bees fan moist air that can’t go anywhere. If the hive is closed at the top, moisture from the nectar condenses under the cover and the relative humidity in the hive stays so high that further drying of nectar is almost impossible. You can help your bees cure more honey by providing adequate through-the-hive ventilation.

Rusty

Why do bees collect on the bottom board?

Brood nest temperatures remain fairly constant throughout the year at 93°-96° F (34-35° C.) But while a colony in late winter may consist of only 10,000 bees, a summer colony averages about 50,000 bees—and in some cases the summer population may reach 70,000+. With all those bees in the hive, the brood nest has to be cooled to keep it at the ideal bee-rearing temperature.

As temperatures increase in spring and early summer, it is not unusual to see throngs of bees sitting on the bottom board near the entrance to the hive. Even early in the morning after a cold night, they may be all lined up, looking like they are about to swarm.

However, congregating at the entrance is normal behavior for this time of year. Think of it this way:

Even a small cluster in the dead of winter manages to keep the brood nest warm. Individual bees take turns pressing their bodies against the brood and, by doing so, the baby bees are incubated at a cozy ninety-some degrees Fahrenheit.

But as the outside temperature gets warmer, so does the inside temperature. In addition, the number of hive occupants rises dramatically. So, instead of having a heating problem, the hive now has a cooling problem. Too many bee bodies sitting on the brood may make the brood too hot for optimum development.

In addition, the vast number of bees in the colony restricts the air flow through the hive. This occurs at the same time that the bees are trying to dry down the nectar and turn it into honey.

In response to these problems, the bees congregate in different places. They begin by sitting on the bottom board. As temperatures rise even more, the bees may “beard” on the outside walls of the hive, or hang in festoons from the landing board. Think of sitting on the front porch to stay cool on a hot summer’s day—same thing.

Follower boards and slatted racks can both provide additional congregation areas—places where the bees can sit without overheating the brood or restricting air flow through the hive. You can also help by providing screened bottom boards, screened inner covers, and upper entrances—all of which increase air flow through the hive.

I am probably guilty of over anthropomorphizing bees, but it is one of the easiest ways to figure out what they are doing and why. We need to stay warm in winter, and so do they. We need to stay cool in summer, and so do they. When we have excess moisture in our homes, we try to remove it—and so do they.

Remember, though, that even if the air feels chilly to you, the bees have huge numbers of individuals in their homes that we don’t have. So even a modest increase in the outside temperature can have a significant impact on the inside temperature, and the bees react accordingly.

Rusty
HoneyBeeSuite

What size hardware cloth is best for beehives?

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 Amazon.com. 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.

Rusty
HoneyBeeSuite

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.

Rusty

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