Anyway, most of the info I've read says that an average-strength colony will consume about 30 lbs of honey during the winter. However, I don't know if that fact takes into account regional differences, so Phil Chandler's advice seems more helpful to me. He says to allow 2 lbs of honey per week of non-foraging weather for a strong colony. BTW, I have no idea how to define "average" or "strong" colony," but more on that toward the end of this post.
OK, let's go back to the problem of calculating how much honey to leave. Say that your non-foraging weather stretches from mid-October to mid-March like mine.
5 months x 4 weeks = 20 weeks
20 weeks x 2 lbs = a minimum of 40 lbs
If you hadn't noticed, I really emphasized the word "minimum" because you should always have some reserves in case things go pear-shaped. What if winter starts earlier than expected? What if a late frost kills the spring blooms? The bees should have some backup stores for emergencies.
Additionally, Lazutin maintains that a colony will build up better in spring if it has at least 20 lbs of reserves. To quote:
"An average-strength colony that is left to its own devices will consume up to 30 pounds (15 kg) and more of honey during the winter...practicing beekeepers have seen that if a colony is left with "just enough" honey in the fall -- just enough, that is, to last until the first honeyflow next spring -- then when spring does arrive the colony will struggle to grow and will be unlikely to build up sufficient strength in time for the main honeyflow. In the spring, the queen will only lay eggs effectively if the hive contains reserves of at least 20 pounds (10 kg) of honey and the bees are certain that the "kids" won't lack for warmth or food. That's why conscientious beekeepers are in the habit of leaving at least 50 lbs (25 kg) of honey in the hive in the fall, and those who are especially caring keep another 20 pounds (10 kg) for each colony around as an emergency reserve to be used for supplemental feeding if necessary.As I mentioned earlier, one of my issues has been trying to define what an "average-strength" and "strong" colony looks like. In his book Beekeeping with a Smile, Lazutin provides the following descriptions for evaluating hive strength. Bear in mind, that one of his extra-deep frames equals 2 deep Lang frames:
- Strong colony: Winter cluster occupies 8-11 extra-deep frames, 5-6 lbs (2.5-3 kg) of bees
- Average colony: Winter cluster occupies 6-7 extra-deep frames (He doesn't provide weight for this, but it should be an average of strong/weak.)
- Weak colony: Winter cluster occupies 4-5 extra-deep frames, 2-3 lbs (1-1.2 kg) of bees
For myself, I try to leave about 15 bars of stores. After weighing various combs, I know that one of my brood combs backfilled with honey weighs an average of 4 lbs. A full honeycomb weighs somewhere between 4.5-5.5 lbs.* Therefore, I can conservatively estimate that I've been leaving about 60 lbs of honey for winter, which puts me on track with Lazutin's recommendations. So far, my bees have never eaten anywhere close to that amount -- not even this past spring when we had such miserable weather, but I'd rather be safe than sorry.
*If you weighed combs from your own hives, you might end up with different weights than me based on the dimensions of your hive.