How much honey bees need for winter, and how to tell without opening the hive

Every autumn the same question comes up in every beekeeping association: how much honey should a colony have to get through winter? The honest answer is a range, and the range depends less on the bees than on your winter. A colony in a mild coastal climate that flies most weeks needs a fraction of what a colony confined for five months in a cold continental winter needs. Here are typical figures, how to measure what a hive actually has without opening it, and what to do about a light one.

The figure depends on your winter

A winter cluster eats slowly through the coldest months and quickly at the end of winter, when the queen starts laying again and the colony warms the brood nest. The longer the stretch between the last autumn forage and the first spring forage, the more it needs. As rough guides:

• Mild winters, with frequent flying days and some winter forage: around ten to fifteen kilos, twenty to thirty pounds.
• Temperate winters, such as most of the UK and Ireland, the Pacific Northwest or New Zealand's South Island: around eighteen to twenty-five kilos, forty to fifty-five pounds.
• Cold winters, such as the northern United States, Canada or central Europe: thirty to forty kilos, sixty to ninety pounds, and more in the hardest places.

Your local association's figure beats any national one, because it comes from beekeepers with your forage and your weather. A large colony, or a prolific strain that keeps a big brood nest, sits at the top of the range.

What a frame of honey weighs

Counting frames of capped honey gives a quick estimate before the hive is closed for winter. Approximate weights of honey in a full, capped frame:

• Langstroth deep: two and a half to three and a half kilos, about five to eight pounds.
• Langstroth medium: about two kilos, four to five pounds.
• British National brood frame: about two to two and a half kilos; a National super frame, about one to one and a half.

So a temperate-climate colony in Langstroth deeps needs the equivalent of six to nine full frames of honey. Part-filled frames count for their share: two frames each half full are one full frame.

Hefting, the everyday check

Frames can only be counted while the hive can still be opened. Through the rest of autumn and winter the check is hefting: stand behind the hive, lift the back a few centimetres by the handhold and feel the weight. It is imprecise at first and surprisingly reliable after a season, especially if you heft a hive you know is heavy, and one you know is light, to calibrate your arms.

For a number rather than a feeling, hook a luggage scale under the handhold on one side, lift until the hive just tips, and read it; do the same on the other side and add the two readings. Subtract the weight of the empty boxes, the comb and the bees, which you can estimate once from a hive you have just inspected, and the rest is roughly stores.

When to check

• Right after the last harvest, to decide how much to feed while there is still time to feed syrup.
• In mid-autumn, to confirm the feed was taken down and capped.
• Every few weeks through winter, by hefting, on a day when you are at the apiary anyway.
• In late winter and early spring, the dangerous weeks, when brood rearing is under way and a hive that was fine at Christmas can run out in a fortnight.

When a hive is light

In early autumn, while the days are still warm, feed thick 2:1 syrup until the hive reaches its target; sugar syrup for bees covers the mix and the feeders. Later in the season, when syrup would not be dried and capped, give fondant or bee candy directly over the cluster, where the bees can reach it without leaving warmth. A frame of capped honey from another of your own colonies is the best winter feed of all, but only from a colony you know to be healthy, because honey and comb carry disease between hives.

Whatever you add, put it where the cluster is. Colonies starve with stores in the hive when the stores are on the far side of a cold box, which is why a colony going into winter should have its space reduced to what it can cover.

Honey or sugar?

Honey is the bees' natural winter food, and many beekeepers prefer to leave a full box of it. Taking the honey and feeding sugar in its place is also common practice and works well, provided the sugar is fed in time. A few honeys are poor winter stores: those that set hard in the comb, such as ivy or oilseed rape, can be difficult for bees to use in cold weather, and honeydew honey, high in minerals, has been linked to dysentery in long confinement. Where those are your late-season crops, feeding some syrup as well is sensible.

Write it down

Note each hive's estimated stores and every feed against it. The notes turn next autumn's hefting into a comparison rather than a guess, show which colonies go into winter light year after year, and, together with the rest of the autumn checklist, give you the short list of hives to check first when a cold snap comes. Feeding is a decision, not a date explains why that list matters more than a feeding calendar, and the feeding records keep it per hive.