Custom-fitting Your Winter Boxes to Your Wintering Bees

At the end of the season, you may have a colony that doesn't have a full set of frames drawn and ready for winter. This happens for a variety of reasons, but the most common one is that the colony was started late (for instance, a late split or swarm) and it simply did not have the time – or foraging opportunities – to gather enough winter resources.

If you have surplus frames of honey (and pollen) from other hives, you can donate them to the under-supplied hive to make up the shortfall. If you have empty drawn comb, you can feed 2:1 sugar syrup to fill their pantry. But, if they have only undrawn foundation to work with, the bees may be reluctant to draw out the additional comb to store the syrup. As the days begin to get cooler, they also may not have enough bees to generate the high temperatures necessary to get the wax-making job done.

Empty space in a winter hive is a problem

Perhaps, at the end of the summer, the colony has only 13 to 17 frames drawn and in use, in a double-deep hive. That's an awkward, box-and-a-half quantity.

One option is to reduce the hive down to match the number of bees and the resources they do have, eliminating unused empty space. You could remove boxes, or move the bees into nuc-sized equipment for overwintering. But this might mean abandoning some filled frames in order to fit the colony into the smaller spaces.

A better solution: custom tailor the interior cavity space to match the resources the bees have (including any donated or filled-with-syrup frames they are allotted).

This is simple to do. And it is beneficial, too, because it organizes a colony in a more vertical arrangement. This reduces the risk that the bees may get "caught" out on one side of the hive and are unable to cross over to the other side when they need to move to fresh frames of honey during the winter.

How to custom tailor winter hives

First, count the total number of frames that the colony has, will get donated, or in the case of empty, drawn comb, that can reasonably be filled with syrup. Then divide that number by the number of boxes you plan to have in your winter hive. Typically, this will be two or three boxes. And then plan on having half (or one-third) of the frames in each box, with any odd frame assigned to the upper box. These frames will be centered in the boxes with the remaining space on either side filled up by wood follower boards and foam insulation panels that you construct. In effect, you will be creating a reduced-width, box-within-a-box. Another beneficial side effect of this plan will be adding a layer of internal insulation along the sides of the hive.

Most people know that double-nucs (usually four frames over four, sometimes five over five) do quite well as overwintered colonies, even in very cold climates. Here at Betterbee, we overwinter hundreds of them every year. The idea of a custom-tailored interior space works along the same lines, except that it de-couples the number of frames that are used from the size of the equipment. You can winter four over fours, or double fives, sixes, sevens, etc., using up even that last odd frame, so none of the bees’ hard work is left behind.

And in the spring when the colony starts to build out, the interior cavity space can be easily – and gradually – expanded simply by removing a foam panel or two, and inserting an additional frame when needed. This elasticity of space avoids one of the problems of overwintered nucs when there is an unexpected burst of nectar resources before they can be moved to full-sized equipment.

What you need:

1. Two wood follower boards for each box in the stack.
2. Homemade spacer panels made from 1” thick XPS insulation foam slabs. For these panels, you want only the solid XPS foam, without any foil or plastic backing. Insulation boards made from compressed pellets of styrofoam will not work. Reject any sheets that are warped. If your project is small, it may be worth asking whether broken sheets are available – they are sometimes free, or sold at a deep discount. How much insulation is needed will depend on how much space must be filled, which in turn depends on how many frames will remain in each box. (See the box below for how to work that out.)

   What is XPS insulation foam?

   XPS foam (industry shorthand for “expanded polystyrene”) may be green, pink, or light blue depending on the manufacturer. It is made for insulating building foundations and is available in 2’ by 8’ panels. If you can find them, larger panels may be less expensive per square foot, though harder to take home in a car. The easiest thickness to cut and use in hives is the 1” material. Two-inch thick XPS is available, but it is harder to cut and fit into bee boxes, and usually isn’t any less expensive than using two, 1” thick panels.

3. Shiny, silver foil HVAC tape. This is the tape used for sealing up HVAC ducts, but it's not the same as "duct" tape (Go figure!). You'll need a roll of 2" wide tape.

1. Tools needed:
   • Measuring tape
   • Straight edge
   • Scissors (for cutting the tape)
   • Long, thin-bladed knife
   • A piece of cardboard, Masonite, or a recycled political sign to make a cutting template for the spacer panels

Step-by-step instructions:

1. The first thing is to consider whether the colony has any problems other than a simple lack of filled and drawn frames. This includes making sure that it is not affected by diseases, pests (especially mites), or a weak or failing queen. These problems must be fixed now, because they will result in winter losses no matter what else you do.
2. By mid-September, count the number of drawn frames in the colony and assess how they are currently being used. Do you have other resources, either drawn and filled frames or drawn frames that can be filled with syrup which might be added? The combined total of frames (the ones belonging to the colony and those that can be added) is what you will have to work with. Divide this number by two (or three if using three winter boxes) and arrange the frames in the center of the box(es), placing any odd frame in the top box. Arrange the frames among the boxes in the same “ideal” pattern as you would for a full-sized hive, with brood on the bottom and honey stores overhead. For the time being, fill the empty space on either side of the wintering frames with empty frames (undrawn or partially-drawn ones are fine for this temporary use – they are just placeholders while you are assembling and creating the filler panels). If you already have the wood follower boards on hand, go ahead and insert them on either side of the wintering frames. Place the follower boards so that they have a flat side facing outward to eventually lie against the foam panels. Getting the wintering frames arranged early on reduces the colony stress when the foam panels are inserted and the hive-width becomes truly reduced.

1. Measure the interior dimensions of the box before closing the hive. Take note of the width of the box. To make a template for the foam panels, also measure the interior length of the box, the box height and the dimensions of the rabbet the frames rest on.
2. Begin feeding if you have added empty drawn combs which need to be filled with syrup, even if the bees are still bringing in nectar. Keep an eye on things; you can always add an additional frame if you have an unexpectedly strong fall flow.
3. Figure out how many spacer panels are needed: Start with the interior cavity width measurement of your boxes. Then subtract from that the space occupied by the frames you’re leaving in the box, the two follower boards and the working space. The remaining space will be filled with the foam spacer panels. Expect that it won’t come out evenly. During the winter you can afford to have a little more, or less, working space than you would normally have in a hive without the risk of creating problems, so there is a bit of wriggle room when working out the number of panels. And if the number of spacer panels needed is an odd number, it’s OK to have an additional one on the colder side of the hive. It’s very important that all the boxes in the hive have the same number of frames, except as noted, the top box can have one extra.

   How many foam panels will you need?

   Measure the interior width of the box.

   Multiply the number of frames you plan to leave in each box by 1.375, and subtract this amount from the interior width measurement.

   Subtract twice the thickness of a wood follower board.

   Subtract 1.5” for working space.

   Divide the remaining space by 1 to get the number of foam panels needed, per box in the hive stack. Ignore any fractional amount left over unless it is more than ¾ inch, in which case add an additional panel.

4. Make a template for the spacer panels. The template is T-shaped, with the same measurements (interior measurement from front to back and actual height) as the box. Pay close attention to the dimensions of the frame rest rabbet to make sure the panels will fit correctly without sticking up (or down on the bottom edge) from the actual dimensions of the box. Make the template a hair undersized, so that there is no chance of the panels being proud of the box, even if you slightly over-cut the foam during fabrication.
5. Using the template, mark and cut the panels.
6. Check each panel to make sure it fits entirely within the box; trim if necessary.

7. 

   Wrap the shiny aluminum tape around the edges of the panels. This will keep the bees from chewing on the panels, as well as strengthening the panel(particularly the vulnerable “ears”) and keep XPS particles out of the hive. If a panel breaks, it can be repaired with tape.
8. Install the foam panels in the hive. Work on the uppermost box, first. Remove any placeholder frames in the box. Scrape the sides of the box to remove any blobs of wax. Slide one panel in tightly against the side wall, gently pushing any bees downward into the space below as you do. Add any additional panels on that side, always keeping them tightly together so bees can’t wander in between them. Remove and reinstall the follower board so that its flat side is tight against the foam panels. Repeat on the other side. Set this box aside and repeat the same process on the lower box(es). When restacking the hive, smoke or brush the bees off the now-wide expanse of foam panel and follower board tops. There will be little or no bee space under the panels so bees would be trapped or squashed. (You won’t be working these hives again until spring so this is not a recurring issue.)

   

   

9. In the spring, you gradually remove the foam panels to add room for extra frames, as needed. When they – and the follower boards - are all out of the hive, just store them. Protected from sunlight, they will last indefinitely and can be re-used over and over.