How much honey does your colony need to survive winter? This question is asked often, and the answer typically falls in the range of 80-100 pounds. This is a safe answer, because it will satisfy the needs of a large colony during a cold winter. But it may not be accurate enough for your particular situation. For example, you may be tight on reserves after the harvest, or have a small colony due to a late split or health issues. If you’re concerned about having adequate reserves, and a hundred pounds is unrealistic, then you need a more accurate answer.

I developed a formula to help beekeepers determine how much honey needs to be on their hive come November. It gives you a rough estimate using data gathered from published scientific research. In the interest of keeping it simple and reliable, a number of conservative assumptions have been made. This should result in an overestimation of required reserves with a comfortable margin of error.

- overall colony health is good

- hives located in the SLC metro area

- winter from Nov 1 to March 31

- average temps based on historical data

- colony population remains unchanged

- no credit for additional nectar gathered

- no recognition of a broodless period

The amount of honey required under these circumstances primarily depends on the population of the winter cluster. Use the following values to estimate the number of bees that will be in your hive at the start of winter (Nov 1):

ONE SIDE OF ONE FRAME DEEP MEDIUM

fully covered in bees, no comb visible 1000 700

less than fully covered, but more than half 750 500

about half covered in bees 500 350

significantly less than half covered 250 200

Don’t wait until Nov 1 to estimate your winter population. You need to know now, so corrective action can be taken. Keep in mind the colony is getting smaller every day, so round down. Use your best judgement to adjust your estimate. If you’re uncertain, then make no adjustments. Play it safe and use the higher number.

Now that you know how many bees you have, you can figure out the amount of honey required. Use your estimate in place of N:

N x .0022

For example, if your estimate is 18,000 bees, you need 40 pounds of stored honey:

18,000 bees x .0022 = 40 lbs

The last step is to determine if you have the required reserves. Add the honey in your hive according to the following values. Adjust for partial or over filled frames:

Full Deep (both sides included) = 6 pounds

Full Medium (both sides included) = 4 pounds

If you’re short, feed one quart of syrup (2 parts sugar and 1 part water, by weight) for every two pounds of additional honey you need to reach your estimate.

Extreme Winters

Honey bees can only sustain flight at temperatures above 55 degrees. Energy expenditure of foraging honey bees is beyond the scope of this formula. For the five months from November to March, the average high temperature in Salt Lake City is below 55 degrees. Temperatures above this point afford the beekeeper an opportunity to feed the colony. Therefore, a particularly warm winter is of no consequence.

The formula does, however, account for the expenditure of honey bees actively producing heat. The estimate should easily compensate for temperatures below normal. If you can’t quite meet the reserve amount, consider insulating your hive to some degree. Colder temperatures result in larger amounts of honey consumed.

REMINDER: This formula only applies to the full period of time from Nov 1 to March 31. Any adjustments to this time frame will not produce an accurate estimate. Results are unverified and it is the responsibility of the beekeeper to ensure adequate food reserves.