Bee Culture, April 2011

The first test of checkerboarding (CB) was expected to produce slightly more honey if it reduced swarming incidence. A colony that did not lose bees to the swarm would have more population to exploit the flow. Anticipating maybe a 20% increase in average production of surplus, the results were surprising. One colony in that outyard produced 7 supers of surplus. Wintering at that time in a double deep with shallow feed box at the top, the most surplus we had seen was about 4 supers. Seven would be a 75% increase. One sample, for sure, but an attention getter. The seven-super producer had queen problems in the preceding fall. Working around the problem of requeening, that colony went into winter with a single deep and three shallows overhead. Thinking that extra production might not be coincidental, we started our shift to a single deep and shallows for wintering configuration. After several years of observation of the advantages, we now recommend the single deep as easier and more reliable.

Note that the 2 ½ deep wintering configuration is not included on the chart. Hives were in a constant state of change with respect to wintering configuration in that period. It took two years to get all-up in a different configuration and was not fully all-up at 2 ½ when we elected to go to a deep and two shallows. The result of the “every-which-way” configurations is that we didn't acquire an average brood volume for the 2 ½ configuration, but I can report that the brood volume was typically somewhat more than the double deep.

Supering optimistically for production, during the calendar period of maximum brood volume, means the stack is building height and that height discourages access to the brood chamber(s) to actually see the brood volume. It took another couple of seasons to learn why the production took a leap forward with CB. It was quite obvious when lower levels were examined that brood volumes were much larger than earlier configurations. Conclusion: Increased brood volume, and the resultant increased population is the key to the increased honey production – and the increase is much more than you could expect from swarm prevention alone. Note that most swarm prevention techniques actually weaken colonies.

The reader has already seen the fig. 1 Seasonal Brood Volumes, and is way ahead of me, but we will wade through it, anyway. The plots are from memory of the first few years of my learning. After two false starts, where colonies didn't survive, about 1990 we were underway and growing colony count. My ignorance of beekeeping knew no limits – didn't know about clubs or literature support. Guessing about what to do next, hives were not standardized and almost no two were the same in the first couple years. Finding and visiting other beekeepers in the area, settled on wintering in a deep and shallow. That's normally plenty for our mild and short winters. In that same time frame, bought some double deeps from beekeepers who couldn't cope with parasitic mites. In the following years we increased and decreased wintering configurations in accordance with observed results. All this to say we saw the effects of several wintering configurations. That info is contained in the chart and reflects multi-year averages of effects. Some years more – some years less.

Field Forage: The plot on the flows is not what you are accustomed to seeing. A plot from a scale hive has sharp peaks and valleys. My take on field forage availability is somewhat different. If there is enough forage out there for all the colonies in a given location to send all the foragers that are available, the peaks and valleys don't mean much. In this area, when it's out there, it is a smorgasbord of sources. The on/off/ transition plot is what the colonies key on for internal operations.

Calendar Months: Although the progression of time should be self explanatory, it is important that the reader understand that the timing of colony operations charted is for the AL/TN state line. Other areas will need to adjust the timing to coincide with their forage development.

Vertical scale for brood volume: The scale is deliberately ambiguous to permit us to overlay different wintering configurations with different size boxes used for brood chambers. You will see how it works as we describe the configurations.

Deep and Shallow

In my area of good build up forage availability, generally, minimal honey (often none) is opened in the shallow at the top. The overhead shallow of honey is saved as the reserve when field forage and flying weather support colony feeding requirements. The result is that brood nest expansion and swarm preparation nest size reduction are accomplished in the single deep brood chamber. Further reduction of brood volume in the buildup is due to the space taken up by stores using four frames in the deep as honey at the outside and pollen adjacent to the brood. The colony can easily meet swarm requirements in the restricted space. An early swarm is generated with minimum effort. Do you suppose that might be why nest scouts select a cavity of about a bushel volume when other cavity sizes are available above and below that volume?

Back to the subject: The colony that reduces brood nest size in swarm preparation by backfilling does not typically increase brood volume for the rest of the spring season. Instead, brood nest size continues to shrink. In spite of brood volume decrease, the population has a safety margin built into the numbers to insure resupply of the wintering honey. That safety margin produces some surplus. Is it any wonder that southeastern production is limited to the 50 to 70 pound range? The smaller the overwintering colony hive volume, the less surplus is produced.

Double Deeps:

Honey production is slightly increased by wintering in the double deep configuration. 100 pounds average is considered excellent by most local beekeepers. Higher colony populations are generated by increasing brood volume into about half the upper deep. The other half of the top box is dedicated to maintaining the capped honey reserve through the swarm preparation period. Expansion and contraction of the brood nest takes place primarily in the upper deep.

Single Deep & 2 Shallows – Checkerboarded

There is still some mystery in why CBing causes the colony to continue brood nest expansion until reproductive cutoff. Not understanding why does not limit our appreciation for this gift. Huge populations are generated by almost an extra brood cycle of nest expansion. If standard management creates populations of 60 thousand bees, we no doubt get populations in excess of 100k often. We don't count bees, but a colony with concentrated bees seven feet high prior to main flow is impressive. More bees make more honey.

The increase in production comes in two phases. The CBed colony also improves honey production by storing nectar overhead before the “main flow”. Brood volume upward expansion is accelerated through the thinned honey by virtue of less honey to consume. Their penchant for filling cells within the cluster generates a couple supers of nectar during the swarm preparation period. That nectar jump-starts honey surplus – it's located above the wintering configuration because of earlier, extended brood nest expansion. That nectar is stored raw and starts curing by brood nest heat rise. The established colony does not have wax-making capability until the start of “main flow”. At that time cells of build up nectar are extended, topped off with pre-dried honey and capped. This honey is a bonus of checkerboarding.

The key to storing nectar overhead prior to “main flow” is enfolding empty comb within the concentrated bees of the cluster – we are still in the frosty morning period of late winter through early April.

The CBed colony, in broodnest expansion, starts storing in the interspersed empty comb overhead promptly after CBing. As soon as the cluster volume covers empty comb, filling the lower edge becomes a priority activity. The colony does not “want” empty cells within the cluster. Storing nectar upward continues with brood nest expansion.

The fully-established colony typically has a three–week period prior to “main flow” when very little nectar is stored at the top. Old literature sometimes refers to that period as the “dearth before the flow”. Locally, that period is the peak of native forage availability – hardwood green-up, with associated early tree bloom.

It is possible, however, to encourage overhead nectar storage prior to the three-week lull by beekeeper manipulation. In the case of double deep early-season reversal, where brood is raised to the top, adding a super of empty comb is often effective, if done on the same hive opening. The colony “wants” liquid feed immediately above brood. The problem with this trick is that it may be done too late. Reversal, if done when there is apparent “crowding”, may follow the start of swarm preparation and therefore is too late to be effective.

The major asset to increased production when CBed is the large work force generated by nearly doubling the brood volume prior to “main flow”. For efficient dispersal of that large work force, have plenty of supers on hand. To get maximum efficiency, they need room to work and can be working in several supers at the same time. In our short flow, dispersal of the work force is a major advantage to honey production efficiency.

Let's get into the chart comparison of brood volumes for the active season, as seen at my location. A few general notes will be provided first:

In the fall the colony adjusts the population of the cluster to be proportional to cavity size and accumulated stores. Cluster size allows for normal attrition of older bees in early winter and consumption of honey for room to start brood rearing in winter. When they get it right (difficult with current problems) they have the wherewithal to build up to swarm potential in a timely manner, with food reserves for the swarm prep period.

Mid-winter brood rearing sustains cluster size pending advent of late winter forage availability. At forage availability in late winter, build up to swarm strength gets underway in earnest.

The colony in build up can double brood volume in a worker brood cycle. No effort has been made on the chart to incorporate the doubling effect on growth rates. Average highs and lows are straight-lined for my convenience.

The colony is motivated during the “main flow” by space at the top needing filling. Brood nest reduction is slowed by that perception. The flip side is that the colony accelerates brood nest reduction when the cavity is approaching filled. They need to anticipate filling the cavity to offset the slow process of reducing population. They do not wait until the hive is filled to start reducing brood nest size. Rethink supering “as needed” (last super 70% filled.) You need to ‘stay ahead’ of the bees. Depending on your supering schedule and the strength of the hive, you should add 1 to 2 supers of drawn comb per week as soon as the bees are working in the top box. We speak in terms of motivation versus “complacency.” The colony that can meet survival requirements in a walk, does so. That's complacency. The colony that perceives that they are not meeting survival requirements can rev it up a notch and do more. That's motivation.

With these notes in mind, we can walk through the local season by the months for the three wintering configurations. For all three, empty comb was maintained at the top for continuous colony motivation. You will notice that the deep and shallow tracks the double deep quite well at a slightly lower level.

February: Locally, forage is normally available. Increasing periods of flying weather between cold fronts gets build up started.

March: Brood nest volume tops out and the backfilling of swarm preparation starts. Some stronger colonies will commit to swarm by starting swarm cells before the end of the month with no beekeeper intervention.

When CBed, the effects of checkerboarding kick in, and brood volume continues to grow for those colonies. No brood nest reduction in March.

April: Colonies that did not “top out” and start brood nest reduction in March change direction in early April. CBed colonies also start brood nest reduction at reproductive cut off, but they have gained substantial brood nest size by expanding into April.

April through early June: The brood nest size on all colonies drifts lower through the flow. When they sense flow trail off in June, brood nest reduction is accelerated. That's critical to protection of accumulated honey stores – reduce “consumer bees.”

Late June through early August: Maintain a minimum brood nest for replacement bees and bees of all ages for the various duties by age.

If honey is harvested in July, the bees need to adjust to the revised overall cavity size. That often results in a speed-up in brood nest reduction. Note on the chart that at harvest in July, the double deep brood volume has been reduced to the bottom deep. Honey fills the upper. At that point the CBed colony sometimes has the equivalent of 2 deeps of brood (1 ½ shown). This is an added bonus in mid season population and is a result of the taller stack and the colony tailoring population in consonance with cavity size/stores. Who knows what kind of difference that would make in production for northern areas where there is less time between the Spring and Fall flows. Locally, it is reflected in sometimes filling supers during the summer doldrums. We don't get that with standard management.

August: The fall build up to rear young bees for wintering starts in early August. They have barely managed to get the brood nest reduced and it's time to change direction again. The CBed colony, harvested in July, is now the same overall hive volume as the double deep. Two shallows are almost exactly the same amount of honey as a deep. The two brood volumes converge and overlay for the fall season.

The honey in the tanks at harvest is almost double. Some years more – some years less. One year that stands out in my memory was a season with a weak “main flow.” Some local beekeepers didn't even bother to harvest/extract. The CBed colonies produced about 80 pounds average. In the weak flow, those strong colonies managed to complete the supers of nectar accumulated in the build up. Only 2 of 20 required a super to maintain empty space at the top during the flow, but the harvest was more than our normal yield with standard management.

In a more normal season, we expect about 6 or 7 supers average of honey with CBed colonies. They seldom disappoint me. Compare that to 3 or 4 with the best of standard management.

We regret, and apologize for, the scattershot comments interspersed through this submittal. We have tried to limit them to notes that affect the subject of brood volume and honey production. Some are unduly brief in the interest of article length. Details of colony internal operations were reported in this magazine in a series of articles in ’03 and can be downloaded from .

In summary, the large brood volumes fostered by checkerboarding make a larger difference in honey production than could be expected by just swarm prevention. Of course, you can continue to make partial honey crops as long as you choose to do so. But if honey production is important, you might consider investing in checkerboarding. It’s more than an alternative swarm prevention gimmick. Seems like I have written words to that effect somewhere before.