By: Charlotte Hubbard & Bob Candido
Method Overviews
Thirteen colonies, randomly divided into three groups, were employed in the experiment. All colonies had screened bottom boards with slider boards inserted, and a mouse-guard entrance reducer. We also installed feeding shims to allow for the addition of sugar bricks if needed. The colonies were comprised of rag-tag configurations of either two deeps, one deep and two mediums, or four mediums. Eleven were 8-frame; two were 5-frame. While some of the woodenware was new, most of it had seen many Winters, although it was absent any major gaps or holes — what you’d find in almost every established apiary. Hives were randomly assigned one of the three overwintering methods. We had stopped pulling honey in August, and offered all colonies four gallons of 2:1 sugar syrup in the Fall.
-VH: In this method, we allowed a 5/8” air vent / upper entrance in the top box if it already had that. Over the top box was a combination feeding shim-quilt box. Styrofoam of (generally) R-5 was attached on all sides except the front. Reusing Styrofoam from previous years, there were occasional gaps and slightly short sides as we fit together the pieces we had.
-CH: Commercial condensing hive kits did not fit our 8-frame equipment or our budget, so we did what good beekeepers do: improvise. We used Styrofoam providing R-30 insulation on the top and R-5 enclosing all other sides, a feeding shim, and sealed at the corners with Tyvek tape. There was no quilt box or upper entrance.
-MM: MM is the overwintering method used by the beekeepers at Michigan State University (a resource we collaborate with often to make sure we are keeping up with best practices). They overwinter 140 hives by anchoring the top against wind — no wrapping or quilt boxes. We simply put a large brick on these colonies, some of which had upper entrances.
Kalamazoo, Michigan, experiences some inhospitable Winters. Beekeepers in our area know that the active season must be spent ensuring that our colonies go into Winter healthy or they will not survive. This is the main message we teach as instructors of beekeeping courses at Kalamazoo Valley Community College’s (KVCC) Community Education and Life Enrichment Program. We know what we teach is successful because, for the last two years, the apiary we maintain at KVCC has had 100% overwintering of its dozen-plus colonies; prior years’ survival has averaged over 80%.
So why meddle with it? We wondered if we could refine our overwinter approach to gain similar results, but with less effort and expense — important criterion for the small-scale beekeeping audience we serve. Overwintering products are becoming more commercially available and we wanted to be able to guide our students whether more intensive preparations may or may not be worth the time or money. Therefore, we decided to study overwintering methods to evaluate what might be optimal for the bees, and which may be passed up.
In the Winter of 2025 – 20261 we compared three overwintering systems to determine which worked best in our small apiary. First was the condensing hive (CH), a method that insulates similarly to a natural overwintering environment in standard equipment. The CH moves moisture up and away from the cluster, and allows it to be reclaimed from the hive walls. We tested CH against two other widely used methods: the ventilating hive (VH) which vents excess hive moisture to the environment, and what we colloquially called the “Michigan Minimalist” (MM). The MM involves minimal Winter preparation, mainly to secure the hive against high winds and small mammals. Until 2025-26, the VH method had been used exclusively in the college apiary.
Our primary goal was to determine if a particular method was significantly better (or worse) by evaluating survival and food consumption November into March. A general recommendation in northern climates is to overwinter with about 100 pounds of honey; we wondered if we could dial back on labor-intensive feeding and expense if the experiment suggested it wasn’t necessary.
A secondary goal was to evaluate the need for specialized overwintering equipment. A common beekeeping lament is the need for space for all the equipment. We were hoping to gain faith in the MM, which doesn’t employ quilt boxes or space-eating panels of insulation.
Finally, we wanted our experiment to be pragmatic. We did not approach this as an exacting science experiment, but instead, as a practical approach, using and reusing materials as one does in real-life beekeeping.
On a bee-autiful, sunny early October afternoon, we instructors and some students gathered to assemble R-30 tops for the CH method. Because varying sizes of colonies had been Styrofoam-wrapped over the years, there was an extensive collection of varying widths and insulating factors. We sliced and wedged insulation equal to R-30 into what would be dedicated wintering boxes, and cut-to-exact-size R-5 insulation for exterior wrapping.
We also double-checked that we had enough feeding shims. In previous years we’d ensured against starvation by mountain-camping white sugar in late Fall atop each hive. With some trepidation, we elected that we would NOT proactively add this emergency carbohydrate ceiling. The shims assured that if we became concerned, we could easily add a sugar brick.
Perhaps the most significant “Winter preparation” had occurred throughout the active season. We profess healthy bees can endure almost anything. Our mite levels had been managed to generally below threshold throughout the season as part of our teaching apiary. Additionally, colonies at KVCC had been inspected as part of the APHIS National Honey Bee Survey, with results that suggested that nosema, mite, and virus levels were all below national averages.
On a brisk early November day, we again gathered to winterize the colonies. While the CH and VH colonies required 30-45 minutes of effort, we simply put a big brick on the MM colonies and wished them luck. All colonies were strapped together for easy weighing and strapped to hive stands in anticipation of wind. As we put away insulation-securing screws, excess insulation, and used razor blades, we speculated how great it would be if overwintering could be as easy as “put a rock on it”.
Data (and sting) Collection
We are community scientists, not trained in designing precisely planned and exactingly executed methodologies. Thus, we used convenient materials and methods — like a suitcase scale and a strap. We looped the strap around each back corner, then hooked the suitcase scale to the strap and recorded the weight, repeated for the front, and summed for a total weight of the hive. This method of collecting weights was a bit inexact, but allowed us to track changes in weight over time suggesting honey consumption.
We weighed each colony monthly.
Learning occurred. The regular monthly schedule of weigh-ins was challenged by work schedules and weather. We learned that ink pens need to be kept warm to record data. And, if you accidentally set the scale to kilograms instead of pounds, the weight changes will be quite alarming until you correct the error. The bricks atop the MM colonies were sometimes frozen in place, and when dislodged with a bit of pounding, the bees let us know they didn’t appreciate it. Stings are rare in January and February in Michigan, but still painful. We arrived one day to find a nuc of the MM method toppled over. Even though it had been strapped together, the hive bodies were a bit askew in the snow. We quickly reassembled them and put a larger rock on the top. It was too cold to ensure it was queenright. We’re delighted to report that they survived.
We had hopes of evaluating the overwintering methodologies with thorough inspections to examine frames of brood and remaining stores, but spring sputtered into the Kalamazoo area. By the time weather and schedules aligned so we could open colonies in early April, they had significant fresh nectar, and one from the VH group had already swarmed. But perhaps more remarkably, they were all very much alive.
Results?
Even with the rigorous Fall feeding, only about 60% of the colonies initially weighed over 100 pounds, with weights like 105, 109, and the highest – 114. Given the weight of the woodenware, no colony entered Winter with 100 pounds of honey (50 for a nucleus colony).
Our conclusions? First and foremost, healthy bees with ample food and at least minimal protection from the elements can survive about anything a Michigan Winter can unleash. Perhaps there was too much imprecision in the methodology and data collected to prove a best method, but it was still insightful. The CH colonies did lose significantly less weight across the Winter relative to the MM and VH – only 25% as compared to about 50% and 40%. That no colony went into Winter with the recommended 100 pounds of honey — we’re left still wondering about that recommendation. With 100% survival, we surmise the different methods did not change their ultimate survivability as much as their health and care before Winter.
While we don’t expect our research to shake up the world of beekeeping, it was a fun exercise to challenge our thought processes. With dozens of combined years of experience, we will continue to better keep bees healthy and thriving through a Midwest Winter.
Special thanks for insights and advice to the staff at Kalamazoo Valley Community College’s Food Innovation Center, Michigan Beekeeping Association District Representative Bill Berendsen, Meghan Milbrath, PhD, and Jim Ledden, PE.
1 During the timeframe of the project (November 1, 2025 until March 31, 2026), Kalamazoo experienced 118 days of below-freezing temperatures (78% of the 151-day timeframe); 55 of those days, the temperature never rose above freezing. The first frost occurred on October 25, 2025, and the last frost occurred on March 29, 2026.
