You can buy screened inner covers from some of the bee supply houses, but they are also easy to make. I bought long pieces of standard 1 x 2-inch lumber, and used the 2-inch dimension to provide the height necessary to elevate the cover, and I used the 1-inch dimension for the front and back.

The way I cut my pieces, the ventilation air goes out the front and back of the hive. You can also reverse the pieces so the ventilation air goes out the sides, the way the commercial ones do. Either way works, although you will get more air flow if the air goes out the sides, which are longer than the width. However, if your hives are close together, having the air go out the front and back may be best.

These are the steps I used:

1. First I cut all the wood to the proper length. I had help cutting the strips, which were ripped from a standard 1 x 4.
2. Then I cut out a notch on each end of the long pieces where the corners will join together.
3. I used a square to assure right angles, then I pre-drilled the holes with a countersink, so the screws could be recessed.
4. If you are going to paint, this is an easy time to do it, but painting is not necessary.
5. I cut a piece of #8 hardware cloth to size, stapled it in place, and then stapled the wooden slats over the edge. The cloth needs to be stretched tight to limit the amount of sag in the center. The wooden slats give you a nice clean edge and they also provide bee space.
6. When you install the cover, remember that the screen side goes down.
7. Center your telescoping cover over the screen so there is room for air to travel out each end (or side).

Rusty
HoneyBeeSuite

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

I’m only about half way through the book—57% if you believe my Kindle—but one recurring theme kept me awake last night . . . ventilation.

In hive after hive, Kritsky details the various ventilation provisions designed for both temperature control and moisture removal. Pottery hives dating back to 500 BCE had lids with vent holes. Skep hives in the 1800s had lids with adjustable zinc ventilators. Some hives in the late 1800s had multiple ventilators with internal thermometers that could be read by pulling open a sliding door. A similar hive featured a perforated floor where air flow could be adjusted with a metal slide. Hive after hive had features that could help the bees stay comfortable.

The original Langstroth hive was a warren of creature amenities that included double-paned glass sides for insulation and moisture control, a sloping bottom that allowed drainage of rainwater, and a screened ventilation port at the bottom with an adjustable panel. As Langstroth’s hive evolved, feature after feature was discarded. Except for bee space and movable frames, what we now call a Langstroth hive bears very little resemblance to the original.

Although many beekeepers view ventilation as a non-essential luxury, many others believe ventilation is key to long-term honey bee health and high productivity. Too much heat causes bees to congregate on the outside of the hive; too much cold can kill a colony. Too much moisture in the summer makes drying honey energy-expensive and time-consuming; too much moisture in winter can chill the bees and promote disease.

As I said, I’ve not finished reading the book. But I assume our indifference to proper ventilation stems from a desire for easy-to-use and inexpensive hives—hives that will quickly give us a return on investment. Have we chosen high honey production and efficient pollination service over long-term honey bee health?

A vast number of new beekeepers fail after the first or second winter. A lot of those beekeepers plunked down good money for a “complete hive kit” or some variation—most of which have no provision for hive ventilation. (Although, since the advent of Varroa mites, you sometimes get a screened bottom board with a beginner kit.) So the nascent beekeeper—already at a disadvantage because of lack of experience—is further handicapped by a deficient hive. This hardly seems fair.

I think it’s time we review a few thousand years of beekeeping history and embrace what those before us knew: ventilation is vital. We cannot raise healthy, productive bees in a stuffy, damp, over-heated, and pathogen-laden environment. Beyond the economic cost, it borders on cruelty.

Rusty

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

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

It all started Wednesday afternoon. As soon as the journal arrived, I scanned the table of contents and quickly settled on an article entitled, “Managing Varroa Part 1.” I turned to the page and hunkered down to read.

My first warning of trouble occurred in the second paragraph with the use of the word “irregardless.” Well, that’s not actually a word. In fact, Garner’s Modern American Usage calls it “semiliterate.” The construction the author was looking for is “regardless,” but he probably got confused with “irrespective.” Doesn’t ABJ have a dictionary?

Later in the article the author uses the word “Phorectic” with a capital P. Why? Phoretic is not a proper noun. Phoretic is not the name of a deity. It’s just a plain old adjective describing an organism that hitches a ride on another. My guess is the writer didn’t know what it meant, didn’t bother to look it up, and decided to capitalize it “just in case.” Doesn’t ABJ have an editor?

But the clincher—the paper airplane maker—occurred in the sixth paragraph. I quote:

In addition to being ineffective for Varroa control, screened bottom boards are also detrimental to spring colony management. For those operating in areas with a well defined (sic) winter season, followed by a cold erratic spring weather pattern, screened bottoms have the potential to cause considerable harm. I base the majority of my case on the following human analogy. Imagine for a moment that it’s mid March (sic) and you’re in Northeastern Ohio. Nighttime temperatures usually average between 25 and 35 degrees. Daytime averages range between 40 and 50 degrees. Under those conditions, would you as a homeowner open all the doors and windows in your house and leave your thermostat at its normal setting until the weather warmed to the point where the furnace was no longer required? Seriously, how many of you would opt for this course of action? Then, why would you ask your bees to do the same thing?

This paragraph implies that, unlike hives with screened bottoms, human abodes are buttoned up tight so that warm air is not allowed to leave and cold air is locked out. It implies we are doing a disservice to bees to allow them some fresh air. And the basis all these implications is how the author thinks houses work.

If the author lived in a cave, I could understand where he’s coming from. But my hunch is that he lives in some kind of more-or-less contemporary North American housing. If so, he probably has a furnace or a wood stove to keep him warm—either of which vents to the outside. He probably has some exhaust fans that are ducted to the outside as well—maybe a fan in the laundry room, the bathrooms, or over the kitchen range—all of which remove warm, moist air from the home.

You cannot vent air to the outside without replacing it with new air—trust me on this. If you could expel air without letting in new air you would create a vacuum and your house would implode sometime after you died of asphyxiation.

He also implies that he keeps his windows closed all winter. Maybe so. But what about the doors? I’m guessing he has at least one door and more likely two—a front door and maybe a back door, a side door, a garage door, or a porch door. Furthermore, I’ll bet he uses them. And every time he uses one, air is exchanged between the inside and the outside.

Air exchange in human dwellings and work spaces is an important health consideration. For example, air inside commercial buildings is now routinely exchanged with outside air at the rate of 15 cubic feet per minute per person in order to provide a healthful environment for humans and to prevent “sick building syndrome”—a term referring to health problems linked to indoor air pollution. That’s one huge gust of air. For more information on sick building syndrome see this EPA site.

Standards are also written to keep homes and residences well-ventilated and free from environmental contaminants. It is recommended that homes that don’t have enough natural leakage be fitted with mechanical devices to actively remove residential pollutants including moisture. For more information on indoor air quality in homes and residences, see this EPA site.

I certainly don’t mind an author expressing a viewpoint different from my own, but it bugs me when the science is left out of the argument. The author clearly states that he is basing his case on analogy–a fine thing as long as you have your facts straight. The fact here is that human homes are anything but air tight.

In the end, I will reverse his final question and ask: “If we don’t live and work in polluted, moisture-laden, poorly-ventilated spaces then why would we ask it of our bees?”

Rusty

• 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.

• Mite treatments should be complete. Ideally, any mite treatments should be completed early enough that a full colony of new worker bees has been produced after the treatments but before winter.

• Bees born after mite treatments are completed are less likely to be infected with one or more of the viruses mites carry.

• Mite treatments administered too late in the season kill the mites but do nothing to reduce the load of viruses in the hive. This is because, unlike summer workers, winter workers live many months. If the winter bees are born before the mites are gone, they can easily carry viruses into the winter, spreading disease throughout the colony.

• The hives need to be heavy with honey. If the colonies do not have enough stores, supplemental sugar syrup needs to be fed immediately. Once the temperature drops too far, the bees cannot break cluster to get the syrup and they are unable to dehydrate the syrup to the proper level for storage. Eventually, the syrup may freeze.

• If pollen stores appear very small or non-existent, place pollen patties on the top bars.

• If you are not using screened bottoms, hives should tip forward slightly to allow rainwater and snow melt to drain out of the hive.

• Reduce entrances for overwintering. Small entrances are important for keeping out wildlife such as mice.

• Provide adequate ventilation. A cluster of bees in a closed environment will produce water vapor that cannot escape. If the vapor condenses and drops back down on the bees, they may die. In most cases bees can survive cold and dry conditions, but they cannot survive cold and wet conditions.

• If you live in an extremely harsh environment and want to eliminate cold drafts, you must still handle the moisture accumulation. Consider the use of moisture boards or Warré-type “quilts” to absorb water vapor.

• Remember that excess moisture in the hive also promotes the growth of molds, fungi, and disease organisms. Even if you live in an area where hives are wrapped with insulation, you must still provide adequate ventilation.

• Ventilation holes should be covered with screening to keep out other creatures.

• Make a final fall inspection. Do you have a queen? Do you enough bees to keep the brood nest warm? Is the hive free of obvious disease?

• • Queenless or low-population hives need to be combined with other hives if they are to make it through the winter.

• • A queenright hive with less than optimum population may be stacked on top of a strong hive with a double-screen board.

• • Diseased hives should be destroyed. Do not combine a diseased hive with a healthy one.

All done? Good job. Time to relax with a pot of hot tea and honey.

Rusty