How to make a moisture quilt for a Langstroth hive

For years I’ve been trying to reduce moisture accumulation in my wintering hives. Then last summer, after much reading about Warré hives, I decided to modify a Warré-style quilt box into something that might work on my Langstroths here in the Pacific Northwest.

I spent quite a while thinking about this and a long time building the quilts, but at this point I am ecstatic about the results. They are really working—no moisture at all is dripping down on my bees. The funny thing is this: the quilts are working in a way that is different from what I predicted—but more on that in a bit.

Here is what I did:

  • I bought a bunch of two-inch supers that were designed to be used as mountain camp rims.
  • Using a one-inch hole saw, I drilled four holes in each frame for ventilation.
  • After I painted the frames, I stapled a piece of #10 hardware cloth over each hole to keep out critters.
  • I bought canvas by the yard, cut pieces to fit the frames, and finished the edges so they wouldn’t fray.
  • I stapled one piece of canvas onto each rim, stretching it as tightly as I could.
  • I filled each “quilt” with wood chips leftover from brood rearing (chicken brood rearing, that is.)
  • I put one quilt frame on each hive. In most cases I placed it above the top brood box and below the telescoping cover. In some of the hives it is above a mountain camp rim and below the telescoping cover.

For some reason my brain was muddled on the next point. I thought the moisture would wet the quilt from the bottom up. In other words, I thought the warm moist air would rise and condense on the canvas and wood chips nearest the brood nest. So I was surprised and confused the first time I opened the hives and discovered that just the top layer of wood chips was wet and the rest of the quilt was dry.

Now that I have de-muddled, it all makes sense. The wood chips are light, fluffy, and basically the same temperature as the air above the brood nest, so the moist air does not condense on the wood chips at all. Instead, the humid air rises and goes right through the canvas and the two inches of wood chips until it hits the cold inner surface of the telescoping cover. Once it hits that cold surface, the moisture condenses (just like in a regular hive) and then rains back down. But instead of the drops falling on the brood nest, they land on the wood chips and are absorbed. It is just so cool!

I’ve opened all my hives several times since I installed the quilts and in each case the inside of the telescoping cover and the top layer of wood chips have been wet. When I stir the chips, it is easy to see that only the surface layer is wet because the wet chips are a yellowish-brown color compared to the dry ones which are almost white.

My original plan was to change the wood chips whenever the quilt became saturated, but so far I haven’t had to. It seems the ventilation holes are allowing the chips to dry in spite of all the rain. The moisture hasn’t seeped down more than one-quarter inch.

While building the quilts I was worried that the 2-inch super would be too shallow, but it seems to be about right for this climate. I think that a very cold climate would warrant a thicker layer—perhaps a three-inch rim like those used for baggie feeders.

I should also mention that the four ventilation holes are providing the sole top-of-the-hive ventilation for each hive. Four holes may seem like a lot, but the canvas and the wood chips prevent a cold draft from flowing across the bees—the air movement is more diffuse because of the quilt. I keep a very small entrance in winter, but I have the Varroa drawers removed so air flows in through the bottom of the hive and out through the ventilation holes.

Rusty
HoneyBeeSuite

First I drilled holes in the supers.
First I drilled holes in the supers.
I painted the supers inside and out.
I painted the supers inside and out.
I stapled hardware cloth over the inside of the holes.
I stapled hardware cloth over the inside of the holes.
After finishing the edges, I stapled the canvas to the rims.
After finishing the edges, I stapled the canvas to the rims.
Finished quilt box from inside.
Finished quilt box from inside.
Quilt box filled with wood chips.
Quilt box filled with wood chips.

Comments

cgrey8
Reply

I live in the Atlanta area. In the summer, it gets quite hot here, so I plan on running a screened bottom board (this will be my first year having bees). And a screened top board would also work well too particularly since I want to restrict entrance to the hive to the bottom (no top entrance).

However we also do get some fairly frigid temps, fortunately just not sustained frigid temps. However cold is cold and short periods of cold can still produce condensation. So a moisture quilt just makes a LOT of sense. But is there a chance to combine the functionality of a screened top board and moisture quilt together into 1 device?

So I want to propose the thought of using hardware cloth mesh in the bottom instead of canvas. In my head, I simply don’t put wood chips in the box in the summer and I have a nice ventilation through the hive. But as the temps drop, fill the box with chips. The chips will act as insulation, moisture capture, and slow the flow of air through the hive (along with an entrance reducer and solid bottom board on the bottom of the hive).

My questions:
1. Is there a compelling reason why canvas is used instead of mesh? I get that canvas will hold more water thus being a final defense against rain in the hive. But it sounds like the wood chips do a pretty good job of that to start with. Rusty’s mentioned a few times that only the top 1/4-1/2″ of her chips are actually moist with the bottom chips being perfectly dry.

2. Are small wood pieces falling on the bees really that big of a deal? I get that it’s not ideal, but does it hurt them? Or is it just work for them to have to clean the pieces out of the hive when it warms? Keep in mind, even in the dead of winter, we get 50-60 degree days inter-mixed with sub-freezing days. As many of you know, Atlanta got hit was a whole 2″ of snow which shutdown the city. Quit snickering. But yesterday & today…50s. Tomorrow, 60s even though each night it gets back below freezing. Point being, the bees will get plenty of maintenance & cleansing flight opportunities through the winter even when we are getting nights in the teens. So I wouldn’t think the effort of having to take pieces of falling wood would be that big of a chore. But I’m a newbie so I’m asking…

3. We commonly get hard rains in heavy winds. If the telescoping cover doesn’t cover the holes sufficiently, I may need to put some kind of rain guards on the telescoping cover. Has anybody had issues with “horizontal” rain causing wetting on their moisture quilt?

4. Does anybody see any major issue with what I’m thinking given my location and intention?

Rusty
Reply

Chris,

I think most of your questions are answered in the post “Tweaking my moisture quilts” and the 30-some comments that follow. The subject of that post is that I changed from using canvas to hardware cloth.

Now I place the canvas on top of the hardware cloth to prevent bits from dropping down. Is this a big problem? I think it depends. Often in spring the debris on my bottom boards is quite thick with dead bees, bits of wax, and other hive junk. Essentially the bees keep a tunnel open through it so they can get out. I cannot see the point of making this debris pile even deeper by adding wood chips to the mix.

If I get a warm day I sometimes pull out the entrance reducer and, using a stick, pull out a lot of the junk. But I don’t always have a warm day, or else I forget completely. So for me, I will stick with the piece of fabric because it is working great.

And, yes, in spring I dump the wood chips and use the quilts for ventilation. When they had cloth bottoms I turned them upside down but that allowed room for comb building. Now that they are screened bottoms, I will just dump them, remove the feeder rims, and use them in place of screened inner covers.

cgrey8
Reply

Perfect! I’m feel reaffirmed that I was on the right track in my thinking. Thanks for the response and I’ll read over the thread you linked to for additional ideas and content.

Thanks again…

Phillip
Reply

I made a few moisture quilts by stapling window screen to the bottom of my ventilator rims. I hammered together a few more with wood from some old baseboards. As it turned out, the design of each moisture quilt was slightly different from the other. Some were a couple inches high with only one ventilation hole on each side. Some were four inches high with two or three ventilation holes on each side. I didn’t worry about the screen sagging down because all the moisture quilts had feeder rims underneath to raise them up. All the feeder rims provided an upper entrance except for one. Bottomline: the design and installation of my moisture quilts is all over the map.

We had severe cold, then lots of rain, wind and fog for most of December, and my hives got soaked inside. They were a mess. A month after I added the moisture quilts — after another month of cold, wet, windy weather — all the hives were dry inside. The moisture inside the hives had been wicked away. I was slightly astonished. I used to put a piece of hard insulation over my hives in the winter because it worked well enough and was dead easy to do. But the extra effort it takes to make the moisture quilts is worth it, because is a relief to know that even under the coldest, wettest conditions, the moisture quilts can keep the hives dry and cosy. One less thing for me to worry about.

My data set is still too small to jump to conclusions, but my initial results are pretty damn impressive. Thanks for passing this one along, Rusty.

Rusty
Reply

Phillip,

That is really good news. I’ve been really impressed with them as well. My hives used to be soaked all winter long; there was condensation under the roof that dripped on the bars, down the sides, and directly onto the bees. It all disappeared with the quilts. But what I think is really neat is that there is still enough moisture to allow the bees to eat hard candy. Some moisture condenses on the sugar, but the excess is captured by the wood chips. Sweet deal.

Karine Pouliquen
Reply

Rusty,
What a great reference blog! I jut love it:)
We had a very cold and long winter in Minnesota, and I lost all my bees. The hives were full and heavy with honey and pollen, but the bees could not get to it…I saw some bees frozen only 2 inches from their beautiful honey.

If you are using a moisture quilt (new for me for next winter) can you still place a candy board? and where do you put it in the hive in the fall then?
Thank you,
Karine

Rusty
Reply

Karine,

I put a 3-inch deep feeder rim (a shallow super or eke) between the top brood box and the moisture quilt. I put hard candy or granulated sugar in the feeder. Enough of the hive moisture lands on the hard candy to make it palatable, and the rest is absorbed by the quilt. I’ve used this system a number of years with great success.

Norton Baum
Reply

Here’s my results after putting moisture quilts on my 4 hives last fall. After losing 50% of my hives each of the last two years I lost ZERO this year! We has a really bad winter here in Chicago but the hives have all come through it with flying colors. A friend who had 30 hives last fall has only 5 left now. He did something wrong. In any event I’am sold This will be a standard fall addition for me from now on.

Rusty
Reply

Norton,

I’ve heard many similar reports. I’m truly a believer.

tyler harvey
Reply

I used quilt boards on my Langstroth hives this year and found a lot of mold upon inspection in early spring. I can’t tell if the moisture overwhelmed the wood chips due to lack of ventilation or if it condensed on the bottom of the canvas. Other thoughts are the canvas is too finely woven although if you hold it up to the light you can see through it, so I’m skeptical of that. I did use shallow supers with three to four inches of wood chips and it was a terribly long, cold winter. I’m leaning toward inadequate ventilation as the reason for my semi-failure.

Any thoughts?

Rusty
Reply

Tyler,

I agree that it was probably lack of ventilation. Although I don’t know how much ventilation you did have, I know this system won’t work without air flowing up through the chips. If the air doesn’t (or can’t) move, the moisture will just condense any old place. I don’t think the weave has anything to do with it; air doesn’t require much space to move around. I wrote a lot about the movement of moisture-laden air and the post, Physics for beekeepers: how does ventilation increase honey production. The processes in winter are very similar.

tyler harvey
Reply

Thank you for the reply

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