Feeding Honeybees in Winter

Capped honey comb

What do you feed your honeybees in the winter? In a word, carbohydrates.

Basically -- and yes, I'm ignoring trace minerals and nutrients the honeybees also need -- when you feed your bees you're either providing them with supplemental carbohydrates or proteins. The key is knowing why they use each.

First, let's be clear about those carbohydrates and protein, because you really don't want to serve your bees a plate of pasta or a platter of bacon. Instead, for carbohydrates think sugar and for protein think pollen.

The honeybees use proteins to build bio-mass. In other words, they need protein to make brood. So in the spring and summer, when they're replacing bees every 28 days or so, they need lots of protein (pollen patties).

But in the winter the bees aren't making brood, certainly not as much (since winter bees survive much longer than in spring and summer).  In the winter the bees are clustering in the cold to keep warm.

And how do they do that? Well, they shiver. Yes, shiver. It's functionally the same thing your and I do to keep warm when we're cold.

Functionally it's the same, but mechanically... They nestle into empty comb cells, internally disconnect their wings, and then shiver the muscles that would normally be flapping their wings. That exercise burns energy (carbohydrates) and produces heat.

So in the winter they don't need supplemental protein, but they do need a lot of carbohydrates to provide all the energy they're expending keeping warm.

And they do expend a lot of energy. A strong colony can easily go through 9 or 10 frames (that's deep body frames) of stored honey over the course of a winter. That's something like 30 to 60 lbs of honey for a strong hive, so remember that when you start harvesting honey. Leave the bees enough. But I digress.

Now in the spring and summer, sugar is most easily provided in syrup form. And yes, there are times to feed sugar syrup in a 1:1 ratio, and other times to feed in a 2:1 ratio. But that's another topic for another season. Maybe I'll revisit this one in the spring.

But in the winter you absolutely do not want to feed your bees sugar syrup. You don't want to introduce moisture into their hive at all. Oh, if it's warm enough you can put open feeding stations of sugar syrup (well away from the hives lest you incite robbing). If the bees go and get it, they know what to do with it. Just don't put any kind of moisture right there in the hive during the winter.

Why? Because water is a giant heat sink. It'll suck the heat right out of the bees. It has been well said that cold doesn't kill bees, moisture does.

I know, I know. Someone is going to say, "If it gets cold enough, the bees can freeze." And they're right. If it gets cold enough, bees can freeze. But how cold does it have to get?

Remember that cluster the bees form? Well, they use the thermally insulating properties of dead air spaces in the comb to establish a rather steep thermal gradient inside the hive. It can literally be freezing in the far corners of the hive, but inside that cluster ball the bees will maintain about 85 - 90 °F (~30 °C). And as long as there are no wayward air currents blowing through their hive, they can maintain that cluster temperature down to an actual outside temperature of -40 °F (which is also -40 °C) (see Mark L. Winston, The Biology of the Honey Bee, Harvard University Press).

So when you hear anecdotal accounts of honeybees surviving temperatures down into the -50s, understand that it's not at all as implausible as you might think, depending on how long it lasts. Still, if it gets cold enough, for long enough, then yes, bees can freeze.

This is also why you should avoid opening the hive in winter. Every time you open their hive, you tear open seams of propolis that they're going to have to repair on an emergency basis. Remember, they need dead air to maintain that remarkable thermal gradient. Even a small air leak can set up a draft that will carry all of that precious heat away, literally on the wind.

And of course, if you put moisture in the hive, it too will suck the heat right out of the bees. In the winter, moisture and drafts are the biggest threat to honeybees. Moisture really does kill far more hives than cold ever will. Hence the saying, cold doesn't kill hives, moisture does.

So how do you feed carbohydrates (sugar) to your bees in the winter? Here's how I do it.

I put an extra super body on top of the hive. I then lay a sheet of newspaper across the top bars of the frames. Newspaper was the medium of old-timey manual web pages. If you can't find any, paper towels will do nicely. I then pour a pile of granulated sugar on top of the paper and cover everything with the hive covers. Yes. The sugar is underneath the inner cover.

This pile of sugar does two things. If the bees need it, it's there and they'll come get it. If they don't need it, they'll leave it alone. In either case, that pile of sugar will serve as a desiccant for the whole hive. If you've ever tried to get sugar out of one of those dispensers on the table in a cafe, you know how efficiently sugar will absorb moisture out of the air.

That's why I add such a sugar reserve to all of my hives. It provides a ready emergency food source for the bees, and it protects them from moisture. Come spring, when you open the hive and discover that pile of sugar has turned into a solid brick, you can know it did its job.

But don't think it's been wasted. Not at all. You can still take those sugar piles, break them up if needed, and dissolve them in water to make sugar syrup for your bees springtime supplemental diets.