How far does feed stretch?

[BjornBee]

I have a good number of 5 over five frame nucs overwintering. So far, most look great. But some are light.

I have been using a three inch shim on top to place dry sugar. I have been doing so for a number of years with good results. So those further north, claiming Americans feeding is "Child's play" can pass on this thread.

The local store I normally buy bags of sugar went to 4 pound bags, instead of the traditional 5 pound bags always seen in these parts.

So I was thinking, if I place 3 bags that is 12 pounds, 4 bags would be 16. I never really ever placed more than 3 bags when they were 5 pounders. So one option is under, and one is over.

So if you have say 3 pounds of bees, or about three deep frames of bees, how long can this sustain the bees under non-brood rearing situations?

How would one at least ball park an educated guess on how long they could last feeding on 12 pounds of sugar vs, 16 pounds.

How far would one pound honey go figuring the caloric value vs sugar?

Anybody know anything?

[AllenF]

I do dry sugar over hives.   Haven't done it this year, been to busy.  But it all depends on the hive on just how much they  take.   Some hives that feel real lights don't get through the sugar and some just eat all through it.   All depends on the hive.  And the good thing with dry sugar is in the spring, you can take the unused sugar off the hive and make it into syrup for spring feeding and food for swarms. 
I have a whole pile of shims that are 1 1/2 to 3 " and everything in-between.   I just dump until I feel they have enough.   I don't know how much in weight.  I would think pound for pound, dry sugar would go farther than honey because of the water in honey.   

[BlueBee]

As Allen says (and you know) it is complicated. :)  There are lots of variables at play.  The best I can do for you is give you a guess and the logic behind my guess.

A “Calorie” is a measure of energy contained in some food source, like sugar.  One could think of Calories in a manner analogous to gallons of gasoline and a car engine.  How long a car will go on a tank of gasoline depends upon how big the tank is and how much work the car engine is doing (HP).  Going up some of those hills in PA is going to burn through the gasoline a lot faster than cruising through the flat corn fields of Iowa. 

So how far does 1 pound of sugar get a colony of bees?   First we need to know the Calories in 1 lbs of sugar.  The web claims there is about 1500 Calories in a pound.  Energy calculations are typically done in Watts so we have to convert those 1500 Calories into units that will end up giving wattage (power).  We need to covert Calories to Joules at this point.  1 food Calorie = 4180 joules of energy.  So 1 lbs of sugar is going to provide the bees fuel tanks with 6.27 million Joules of energy.  Seems like a big number!

Now we just need to know how fast the bees are burning their fuel.  The rate at which bees burn those Calories (Joules) is Watts; a unit of power.  1 watt of power (heat) = 1 joule of energy consumed / second. 

This is where the guess work comes in: 

How much energy does the cluster really generate to keep the center warm enough through the winter?  I haven’t measured it, but the numbers various people throw around is 20 to 40 watts for a full sized colony when it’s cold outside.  For a 5 frame nuc, my guess is they’ll max out at about 10 watts.  On average, I would probably guess somewhere around 7 watts. 

If we take a guess and say your 5 frame nuc of is generating 7 watts of power/heat to keep the inside of the cluster warm, then we can calculate how long 1 pound of sugar will last. 

We know 1 watt = 1 j/s, so 7 watts = 7 joules/sec.  There are 60 seconds per min, 60 min per hour, and 24 hours per day = 86400 seconds per day.  7 joules/sec x 86400 seconds/day = 0.604 million joules/day.  Soooo….. a nuc cluster that is making 7 watts of heat to stay warm is going to consume 0.604 million joules of energy every day.

Earlier we found that a pound of sugar has 6.27 million joules of energy in it.  If the bees are burning through 0.604 million joules a day, then 1 pound of sugar will last about 10 days. 

So 12 lbs of sugar should keep your 5 frame nuc running for 120 days if their engines are idling at 7 watts on average.

How’s that for a guess?  :-D

[RHBee]

Impressive.

[VolunteerK9]

Can you find a food distributor in area?  I'm getting busted 50 pond bags for nearly nothing

[AllenF]

You been going to Sams and Costco and cutting the bags again?   

[BjornBee]

Bluebee,
Thank you for that explanation.

While it seems 12 pounds of sugar would not last that long just thinking about it, I have most nucs with the mentioned amount of bees, always having sugar left over in the spring. Very few require more feed, and most I am pulling it off into buckets come spring. Of course the unknown factor is not really knowing how long they fed on honey stores until they started in on the sugar.

I think you put it into perspective, that sugar probably lasts longer than one might think. And that a couple bags of sugar is well worth the investment when needed.

Thanks again for that detailed post.

[rdy-b]

 kinda wonder if you cant just compare it to syrup--12lbs of sugar is about 1 gal of 2-1 syrup or better
 how long dose a gal of syrup last ??seams to me its about two deep frames worth of feed-how long
 will that take the nucs-?? :) RDY-B