Beekeeping Tips & Tricks: Overwintering

November 16, 2020


Animals have a variety of methods for coping with cold weather: some grow thicker coats of fur or feathers, while others hibernate in underground dens. Honeybees, as eusocial creatures, depend on each other, and work cooperatively to keep their colonies alive through cold weather.

Through October and early November, our beekeepers visit as many as 50 beehives a day.  Important housekeeping and data collection occur during these visits:

  • They assess each beehive’s population and record data on size, health, honey stores, activity and presence of a queen. Determining whether a queen is present can take careful examination of the entire hive. If she isn’t found, they’ll introduce a new queen into the hive.
  • Then the beekeepers go through the inner contents, frame by frame, determining which are unused, meaning the wax combs are empty of nectar, pollen, honey or brood, removing all of these “blanks”.
  • With the remaining, active frames, they’ll reorganize the beehive, placing the brood in the center, with space around them for honeybees to congregate and warm the beehive. They set up the built-out frames, containing wax comb and food stores, around the cluster of bees. This process often leads to consolidating down to 1-2 boxes.
  • If the beekeeper determines that the colony has more than enough honey stores for the winter, they’ll take out some full frames for harvesting. If supplies are low, they’ll give the colony one last feeding of sugar in liquid form.
  • One of the last steps is assuring proper ventilation—too open and the colony can freeze, too closed and water build-up from low ventilation can harm them. Beekeepers will reduce the bottom entrance and check on the size of the internal cover’s notch to assure proper ventilation. They will tip the beehive slightly to ensure any water build-up can drain out.
  • Checking for Varroa mites is a critical final step. Out-of-control Varroa mite infestations in winter can be fatal.  To prevent infestations, beekeepers collect a sample of approximately 300 bees and perform an alcohol wash, observing the number of Varroa mites that settle to the bottom. If there are Varroa mites present at levels of 3% or more of bees, they mark for treatment during the last visit of the season.


A cluster of honeybees on a frame

In the final visit, in late November or early December, our beekeepers will take care not to disturb the colonies, as the weather may be quite cold and the bees dormant. They’ll check one more time on the size and health of each colony. If there were Varroa mites on the previous visit, they’ll apply one more treatment in the form of a liquid oxalic acid dribbled on the cluster between frames. If there’s any remaining liquid feed, they’ll remove that to reduce moisture content. Last but not least, the beekeeper may also add a honey board to provide any lightweight colonies with the food stores they need for winter months.

It’s a busy time for our beekeepers, but their diligence and hard work are well worth it.  The bees are tucked in for the winter in snug, healthy hives, and both our colonies and our clients have plenty of nutritious honey for the months to come.


Honeybees will leave their hive in the winter when temperatures rise above 57° F

What do bees do in winter?


During the course of the spring and summer,  honeybees amass stores of honey to provide nourishment during the winter.  In early fall their queens stop egg-laying, and older bees are allowed to die off to limit the demand on their food supplies. When daytime temperatures fall below 57 degrees Fahrenheit, they retreat to their hives and huddle together next to their honey supplies to stay warm and protect their queen.  When outside temperatures fall to 23 degrees, the bees on the inside of the cluster begin to vibrate their wings, generating heat to maintain an optimal temperature of 95 degrees within the cluster centers, where their queens are housed. During the course of the winter honey bees cycle between inner and outer layers, allowing near-frozen outer bees to rewarm, while their replacements take up position as living insulation on the clusters’ exteriors.

It’s a highly efficient survival strategy that, under natural conditions, assures most colonies will survive until warm weather when new supplies of pollen and nectar reappear. There are a number of manmade and natural threats, though, that can impact hives’ ability to survive:

  • Limited sources of pollen and nectar in late summer and fall can leave hives with stores of honey that are too small to feed them through the winter.
  • A weak queen who produces small broods can mean there aren’t enough bees to generate the heat needed to survive extreme cold. Exposure to pesticides can have the same effect.
  • Any unwanted moisture hives can bring hive temperatures down to dangerous levels.
  • Parasite infestations—such as varroa mites—can weaken and kill enough bees to compromise their ability to stay warm.

Today, more than 40% of northern colonies are compromised and don’t make it through the winter; without the help of professional beekeepers, the mortality rate would be much higher. Here are some tips and tricks from our expert beekeepers on preparing a beehive for the winter:

  1. Adjust the position: assess the positioning of the hive; while it’s not essential that it be perfectly level, there should be no discernable tilt, or moisture will build up in pockets. The bottom board must be tilted approximately 1-2 degrees downward, to allow moisture to drain away.
  2. Check the weight: Hives are weighed to determine the volume of honey available for the winter, and to determine the frequency and volume of supplemental feeding required. You don’t need a scale for this— a simple lift will do.
  3. Feed your bees: Be sure that your beehives have enough honey to survive the winter. If not, supplement with fondant.
  4. Treat your hives: Dribble the cluster with Oxalic Acid. This is the final treatment to prevent varroa mite infestation for the year. With no capped brood left in the hive, varroa mites have nowhere to hide, and are easier to knock out. Beekeepers apply it in between the frames beginning with the bottom-most boxes that contain bees.
  5. Ventilate: check to make sure there’s a large-notch inner cover in place, and that top ventilation is opposite from the bottom entrance to the hive. This will assure cross-ventilation, reducing the chance of deadly moisture build-up.

The Best Bees cycle 10 experience is the last phase of our beekeeping calendar, marking our last chance for winter feeding and to inspect and clean out colonies that have not survived. While our process may differ from backyard beekeepers, there are still many similarities. Continue reading to learn more about our feed supply and hive assessment best practices during the winter period.

In order for us to understand what makes bees hardy and survive the winter, this late-winter assessment is fundamental for research purposes. For example, colonies flagged for Grafting and Splits will show a high likelihood of overwinter survival, hygienic behavior, high honey production, and a calm demeanor.


Supplying Feed to Bees during the Winter


Bees live off of a finite storage of honey during the winter. Many colder climate areas are without the plants and flowering blooms that provide nectar for the bees. To counter this, we feed low-resource colonies during the winter months to avoid the starvation of the colonies. These winter checks are brief to minimize the exposure of cold air that could possibly damage the cluster.

Because bees consume food faster closer to spring, our research has shown that the best way to support living colonies and bees coming out of the winter is through winter feeding, pollen patties, boosts, and adding splits. It is important to supply feed to bees so they do not starve before the nectar flow begins.


Winter Feeding Methods


There are many ways to feed a beehive in the winter:

  • Pollen patties: a pollen substitute that stimulates brood production.
  • Heavy stickies: sharing frames from neighboring beehives that are rich with resources including netcar, pollen, and honey.
  • Honey-board: a unique method of feeding to the Best Bees Company. It’s where we essentially lay a blanket of honey on wax paper coated in sugar on top of the hive’s inner-cover.

Approaching Hives in the Field


When assessing a hive during the winter, there are a few things to consider when approaching the hive. We routinely look for and recommend keeping an eye out for the following signs of beehives that are alive:

  • bees flying close by (unlikely during very cold days)
  • melted snow around the hive (the heat of the cluster can melt surrounding snow, especially at the entrances)
  • dysentery streaks (bees relieve themselves over the side of the hive to avoid soiling their living space)
  • fresh dead bees on the landing board or ground in front of the hive (this is an indication that workers have been dragging out their dead even in winter).

Checking Live Hives during the Winter


This is a crucial period of time for survival and the colony should be disrupted as little as possible. Below are the Best Bees methodology for checking a live hive:

  1. Before you open the hive, feel the weight of the hive by gently lifting from the back of the bottom board. If it feels lighter than desired, prepare to feed.
  2. Assuming weather conditions are acceptable, gently lift the top cover only (leaving inner cover in place) and check for life through the hole in the inner cover and by listening.
  3. If alive and the hive feels light or the bees are right at the top, lay a honey board on top of the inner cover. Using a hive tool, gently poke a hole through the middle of the honey-board and into the hole in the inner cover, creating access for the bees to feed.

Note: if temperatures are warm enough, you may be able to open the hive up a little more. In this case, consider adding heavy stickies for the bees to enjoy.

  1. Place the top cover back on, making sure not to obstruct existing ventilation. This is a good time to make sure it is still properly ventilated.
  2. Clear fallen bees from the bottom entrance so that they can continue to remove dead bodies and make cleansing flights.

Overwintered beehives can be hard to spot! Before you clean out a hive you deem dead, make sure you are certain. Here are some tips to help.

  • If the cluster is motionless, remove some bees from the outside of the cluster and try warming them up in your hands. If they don’t revive, the colony is most likely dead.
  • Bees with their tongues out can be an indication that they are dead.

Preparing for New Installs


When we visit a new client to install equipment during cycle 10, we consider the following points for beehive location on site:

  • Flight path not facing direct human activity
  • Avoid areas that will become overgrown or shaded with vegetation. This is hard to tell during the winter, but it is important to keep in mind.
  • No ladders for access to beehive (too dangerous)
  • Avoid damp areas
  • Try to face the beehive towards the sunlight
  • Consider a windbreak if windy.

Countdown to Spring


When we return to our hives, spring will be upon us. We’re looking forward to installing new colonies and making sure our overwintered colonies are on track for another successful and bountiful harvest season.

We aim to track hygienic behavior in beehives closely as the year progresses. We’ll do this in our various research apiaries and queen rearing apiaries. Doing so will help us to determine what behaviors and signs make for a strong colony that is likely to survive the winter.  As always, we’ll record this information in Bzzz, our proprietary hive management system.

These steps are a bit complicated, and doing them right can be tricky, especially at this critical time of year. That’s one reason why our residential and corporate clients hire us to tend bees for them. If you’re new to beekeeping, you can learn more about what our professional beekeepers do to prepare hives for winter  in our blog “Tucking Our Bees in for the Winter.”

Want more information? Here’s some good advice from friends in the beekeeping community:

Whatever happens to your bees this winter, don’t give up. Successful beekeeping takes many years of practice. You’ll face new challenges every year, and through them, you’ll grow smarter and your bees will grow stronger and healthier!

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