A Question Of Size
By John Whitaker
After keeping bees for several years I have started to question the assumptions upon which my beekeeping methods are based. The first of these is the relative merits of using different sizes of brood. As all my equipment conforms to British National standards I have the choice of:
- using a single National brood box;
- using a national brood box plus a super (brood and a half);
- using a 14 x 12 brood box.
When I started beekeeping I was taught that a thriving colony would require a brood and a half. In addition this arrangement gave a quick method of checking for queen cells as these would be built hanging below the upper box, and so could be spotted by simply lifting the upper box at an angle.
Unfortunately my bees have never filled a brood and a half with brood and would appear to not to have been concentrating when taught about where queen cells should be built. And finding a queen, whether marked or not, is at least twice as time consuming as in a single brood box.
For years I have been willing to accept that my unsatisfactory experience with this arrangement was due to my own shortcomings as a beekeeper, but now, while retaining the above explanation as an option I am now willing to question the method.
For a while I have considered introducing deep brood boxes. It is the cost that I find a discouragement. Frames, boxes and foundation are at least 50% more expensive than for normal national brood boxes. Maintaining both deep brood and normal brood boxes adds to the complications of managing my hives.
So now for some mathematics. The different brood box systems are primarily designed to provide the appropriate number of cells in the brood area. So how many cells are there? I calculated that the area of a worker cell is 23.9 sq mm. The formula for the area of a hexagon is: Area = 6 x 0.5 x 0.866 x d x d where d is the length of the side. By measuring over twenty cells of foundation I was able to determine, with a little trigonometry, that the length of a side of a cell is 3.032mm. No doubt there is an accepted value for this tucked away in a text book somewhere.
The books I have available to me suggest that in a good colony of honey bees, the number of brood cells peaks at about 40,000 in June. I'm sure there will be colonies that perform better than this, but I hope this would be accepted as the basis of discussion. A peak of 40,000 brood would result in a colony of between 70,000 and 80,000 bees.
From the table above it can be seen that even with just a single National brood box less than 70% of the available cells are required for brood. Certainly some of the available cells must be used for pollen, and some will empty, being cleaned for the next batch of eggs. But we do not need, in mid season, combs of granulated honey, damaged comb and two wasted surfaces of frames positioned right up against the sides of the box. So I am led to the conclusion that hive management would be simpler and cheaper if a single brood box were used, and there would be no loss of production provided 2/3 of the available cells were used for brood. So is this possible?
After a lecture given by Ian Molyneux at the Bishop Burton conference, I was encouraged to use the Shook Swarm Technique. The technique is well documented. I decided that in my situation the best time to do it was immediately after the rape flow ceased and the rape honey had been removed. This technique was originally developed as a method of disease control (EFB) in which case all the old frames need to be destroyed. Where the technique is used as a part of yearly colony management, such ruthlessness is not necessary.
Supers can be given to other colonies, drone brood and damaged frames go straight in the solar extractor, and worker brood frames given to weaker colonies. If there are queen cells present these can be used to make up a nucleus.
So the result is equivalent to a very strong swarm at the beginning of May. In a normal swarm there are just flying bees; in a shook swarm there are also nurse bees. All instincts to swarm are laid aside. In my limited experience this technique results in an exceptionally vital colony. The queens are soon laying a tight brood pattern across the full brood chamber.
The honey crop has exceeded, by far, what I have achieved from a single colony in the past. Maybe I was lucky and I know this year has been exceptional. The technique has a number of other benefits:
- many of the viruses and pests are removed with the old frames, so the colony is healthy;
- the relentless increase in the number of varroa mites is halted by the break in production of brood;
- the brood cells are full size, resulting in stronger new bees;
- the new foundation encourages the queen to lay in a tight pattern across the full frame;
- the procedure gives an ideal opportunity to change your hive set up, or introduce a new queen.
Of course there is a cost: 11 sheets of BS deep foundation £7.50 plus 4 Kg of sugar £2.40 = £9.90 = 5 jars of honey - not too bad.