In a sense, a honey bee colony spends all year getting ready for winter: A hive makes new workers in spring so they can gather nectar all through the warm season, and then they ripen that nectar into honey that they eat to keep warm all winter. As a beekeeper, what should you focus on at the end of the beekeeping season to help your bees survive the coming winter? These four action items help improve winter survival rates for your bees.

Varroa mites on a mite monitoring screen

#1: Control varroa mites

Winter survival requires populous healthy colonies with plenty of young “winter bees,” the bees that grew from the last few batches of brood back in the fall, before the queen took her winter break from egg-laying. They actually live for about six months — all fall and winter — and start to raise young bees in spring. Instead of wearing themselves out in 6 weeks flying to flowers like summer bees, they huddle together and nibble on honey. About 6 to 8 weeks before the first trees bloom those winter bees start raising the first spring bees.

The key to healthy winter bees is varroa control before the winter bees are produced. Varroa mites and high virus levels connected with mites are leading causes of honey bee colony death. Viruses associated with varroa:

  • Affect the bees’ ability to shiver and stay warm
  • Harm their digestive systems so they can’t actually use the food they eat
  • Hurt their immune systems so they don’t fight off other viruses or bacteria (such as AFB and EFB)
  • Impair their ability to detoxify any poisons in their bodies
  • Damage their brood food glands which are needed to feed next spring’s baby bees

How to control varroa mites

Monitoring of varroa levels is the basis of effective mite management. Low mite levels and resulting low virus levels will give your colonies the best chance of survival. To protect your winter bees, your varroa control should start no later than mid-summer. Our recommendations are based on our location in upstate New York, halfway between New York City and Montreal.

Choose your varroa mite treatment based on season and need:

  • Our favorite summer treatment for honey-producing hives in our region is Formic Pro.
  • For our nucs, we usually use Apivar.
  • Besides treating during the summer and sometimes early fall, we also give an oxalic acid treatment in December, when our bees have little to no brood.
  • Apivar is a very suitable treatment for any region at this time, as long as your hive has no supers. Apivar must be removed in 42 to 56 days, which may require snowy work during the winter.
  • Hopguard3 or Apiguard are other options that require repeated treatments to be fully effective at knocking mite levels down.

Beekeepers who opt to not manage mites should expect much higher winter colony deaths. We believe all beekeepers should do something in the battle against varroa mites. Besides their own colony deaths, they are contributing to the downfall of local bees near them. As their unmanaged colonies weaken in late summer and in the fall, mite levels get very high. As a result, their mite load is transferred to other colonies as far away as 2 miles when strong healthy colonies rob honey from the dying colonies.

#2: Provide adequate food stores

"Capped

Another requirement for overwintering success is offering plenty of food for the bees. This generally means DO NOT OVERHARVEST HONEY! Your hive should have about 90 pounds of honey going into the winter (this means a full wooden hive will weigh about 140 lbs). Even when we don’t overharvest, syrup feeding is still sometimes necessary due to late swarming, or weather that prevented bees from collecting enough nectar during summer. 

Supplemental bee feed in winter

Adult bees survive the winter eating honey, but sugar syrup can be an acceptable substitute. However, it must be fed well ahead of cold times so the bees can take it in, thicken it up, and store it in cells. Syrup feeding (2:1 sugar syrup in fall) should be completed before cold weather arrives. Do not feed sugar syrup unless daytime temperatures are steadily above 50 degrees F. We like to complete syrup feeding before mid-October here in Greenwich, NY.

Our hives go through winter in two deep hive bodies or (rarely) two deeps and a medium. Stored honey can be estimated by hefting the entire hive at one lower edge. Tipping a hive up an inch or so should be extremely difficult. This means they have enough honey. If not, feed! Our light hives can easily take down a gallon of thick syrup every two days. 

Food stores can be assessed during the winter months by removing the outer cover and looking into the hive through the hole in the inner cover.

  • If honey remains at the top of the hive, the colony doesn’t need feeding. You can see capped honey by peeking down into the gaps between the frames.
  • You might instead see the edges of empty cells and bees. If the bees are at the top of the hive, you may need to feed the colony using winter patties, candy boards, fondant, or granulated sugar.

Bee Feed Note: We never feed liquids during periods that the bees are confined to the hive by cold, because then their guts will be full of liquid, and they only relieve themselves during flight. Since they can only fly when it’s roughly 50 degrees F or warmer, offering liquid feed can cause serious trouble during a cold winter. Stored honey, or solid forms of supplemental sugar are the best options when it’s cold.

Early spring bee feed

The bees also need pollen stores to begin rearing brood in late winter, before new pollen is available to foragers. Offering Global patties can help with this in the very early spring. However, if you give bees a pollen substitute, you must make sure they always have some available until natural pollen appears on spring flowers. If they run out, the bees will begin raising a batch of brood and then will have to cannibalize some larvae to feed to others. Either supplement pollen consistently or skip the pollen patties entirely and let the bees rely on their own stored pollen while waiting for the local crocuses to bloom.

#3: Ensure adequate ventilation and add insulation

Moisture can kill bees, so most beekeepers maintain both top and bottom entrances through the winter so moist air can escape the hive. If using inner covers with notches, face the notch down to provide both an easy upper exit and ventilation. 

Using an insulated outer cover (like our insulated wooden cover or our BeeMax cover) or an insulated inner cover, or just putting a piece of 1” foam insulation between the inner and outer covers, can help your bees retain heat and manage condensation.

In the Betterbee apiaries, we use insulation between the covers, reduce the lower entrance to 3 inches by 3/8 inch, and turn inner covers notch-downward. In most of our yards, the hives are protected by natural windbreaks. In others, we build windbreaks.

An insulated hive wrap (purchased or homemade) will keep the hive’s temperature steadier. This is especially important in very late winter as the first generation of brood is being raised, but the cluster is at its smallest size. An insulated hive — like our polystyrene Lyson or BeeMax hives — or an additional insulated wrap or Bee Cozy over a wooden hive allows your bees to retain more heat while using less of their heating fuel, AKA honey!

#4: Protect bees from mice

Metal mouse gaurd

Install a metal mouse guard before the cold weather sets in to keep mice out of the hive. Do this on a warmish day when bees are going in and out, so you can be sure that no mouse is already in there! A little smoke and a hive tool will help install it, and your bees won’t have to play host to any hungry, smelly, messy visitors during the winter months.

Improving your bees’ winter survival rates depends on your efforts before the leaves begin to change. Follow these four tips to help your bees stay healthy through the winter and flourish when spring flowers begin to bloom. For more beekeeping advice from our experts, explore our Beekeeper Guide.