Horizontal or Vertical?

At the beginning of the main swarming season in 2012, I made the decision to stop keeping bees in horizontal top bar hives and move to using Warré hives.  For those unfamiliar with Warré hives, I will write more about them elsewhere.  This page is about my primary reasons for changing hive type after 5 years of keeping bees in horizontal hives.  I should emphasize that all experiences are individual and one should not be too quick to generalize.  However, I hope what follows is of use to those who may be considering what sort of hive in which to keep bees.

My original choice to keep bees in horizontal hives was, in fact, no choice at all.  It came about because, at the time,  all the sites that I found on the internet about natural beekeeping promoted only horizontal hives.   So I was unaware of alternatives such as the Warré hive.

Coming from a background of conventional beekeeping, I was a little dubious about bee colonies expanding horizontally, rather than vertically, but experience quickly showed that they will do this quite readily.  So the objection that is sometimes raised, that ‘bees won’t move horizontally,’ seemed unfounded.  Beyond that, I found that bee colonies will generally place their brood nests near the entrance of the hive and set up a distinct honey storage area away from the entrance.  So another supposed objection, that ‘without a queen excluder, the bees will mix honey and brood indiscriminately’ also seemed to fall by the wayside, at least for the time being.

A further question that arose was whether to have entrances in the middle of the of the hive or at the end (either at the end of the long side or on the end proper).  Some web sites advised one, some the other.  Middle entrances seemed to me to introduce a question about which way to expand the hive as it grew – left, right or both?  I allowed the bees to decide by giving colonies both types of entrance.  The bees voted for end entrances, using these in preference when both were available.

The next issue to be addressed was how to persuade the bees to follow the top bars when building comb.  This took a bit of fiddling.  Eventually I found a design of top bar that gave unequivocal signals to the expanding colony.  Even with clear comb guides, however, I found it necessary, especially with swarms,  to add top bars only one or two at a time and to keep an eye on proceedings until several straight combs had been built.

Moreover, I found that colonies often wanted to build widely spaced combs in the honey storage area and preferred closer spacing in the brood area. Using top bars of an equal spacing throughout the hive led to combs being built increasingly off centre, particularly in the honey storage area.  So I started using spacing shims between the top bars.  Using the shims in different configurations enabled me to vary the spacing between the brood and honey storage areas without having the inconvenience of using top bars of different widths.   In addition, removing the shims either side of a top bar gave a degree of wriggle room when removing an individual bar from the hive.

The next thing I noticed was that the bees had a marked tendency to ‘hang out’ on the bottom mesh below the hive.  Whole festoons of bees would cluster below the mesh for days on end.  I concluded that this was a heat, and possibly humidity, control mechanism; removing bees from the face of the combs allowed for better air circulation.  My response to this was to increase the depth of the hives and to create a false floor that prevented the bees from building comb all the way to the bottom of the now enlarged hive.  Thus the bees would have space  inside the hive to ‘hang out’ below the combs.  And that is exactly what they did.

At about the same time,  I had been experimenting with open versus closed bottoms to the hives, and had concluded that closed bottoms gave colonies more control over internal hive conditions.  The combination of ‘hanging out space’ and closed bottoms seemed a good one.   I had also taken to placing  a bag of wood shavings in the roof space above the top bars, to keep the warmth in during cold weather and to protect from the direct heat of the sun during hot weather.

Then came a spell of warm summer weather that coincided with a heavy honey flow.  I was delighted to see the bees add bar after bar of newly built comb, chock full of honey.  That is until I realized that, below the bars, unseen by me, comb after comb had collapsed.  Some of the collapsed combs were in the storage areas of the affected hives, but others were in the brood nests.  The latter were combs that had become empty of brood and had been used for honey storage because no other space was available.  What a mess; for both the bees and me.  Cleaning it up meant considerable disruption and I could see that some degree of comb strengthening was urgently needed.  After a good deal of experimentation, the answer that I came up with was the use of 6mm diameter dowels, set into the top bar and extending vertically downward about 100mm.  I put two such dowels in each top bar,  spaced roughly 100mm in from each end.   It seemed that dowels of 6mm or less in diameter are incorporated by the bees into their comb, giving much needed extra strength.

The comb collapse episode started me thinking, however.  Both the hives and the roofs were made of thick wood (25 mm or more).  This, together with the wood shavings above the top bars and closed bottoms, meant that short term changes in external temperatures should not unduly affect the temperature inside the hive.  I had in mind the damping effect that one gets in a thick walled, small windowed, thatched cottage of the sort in which I grew up: cool in summer, warm in winter.  Yet the comb collapse episode suggested to me that something else was involved.

To create hexagonal cells, bees form a cluster and heat the wax they exude to 40°C.  At this temperature, wax goes through a phase change and becomes very malleable.  Could it be that the heat created by the bees to form new comb had spread to the completed, and now full, storage combs, causing them too to become soft and malleable?  If so, it would suggest a problem with heat distribution within the hive.  Or to put it another way, a problem with keeping one part of the hive -the comb building area- warm while keeping an immediately adjacent area -the storage combs- cool.  This was not a problem that I had seen in years of keeping bees in conventional vertical hives and is not a problem that I have seen in Warre hives.  If this was so,  it could be imagined that the collapse of the first comb would make the problem worse.  In slumping against the walls and floor of the hive, the collapsed comb would impeded air circulation, making any heat pocket harder to dissipate, increasing the likelihood of further comb collapse.  Not a cheering thought.

The year following the one in which the comb collapse occurred was a quiet one for bee colonies where I live.  Which brings me to the spring of this year.  It was marked by a period of unusual early warmth and bee colonies showed signs of rapid early expansion.  One of my colonies had gone into the winter occupying almost a full hive as I had not harvested any honey from it in the autumn.  I decided to use the warm weather to take a look at the colony to determine its status.  If it had room and was expanding well, that would be fine, but I was a little concerned that the large amount of stores it had carried into the winter might be restricting its space.

It turned out that I was partly correct.  Rather than having a single unified brood nest, bounded by pollen stores and, beyond that, a honey storage area, I found that the brood nest had become fragmented, and was partially separated by intervening combs of honey.  It was not possible to completely fix the problem without causing unacceptable disruption, although I did manage to introduce some empty top bars to allow space for expansion.

Then the weather turned distinctly cool.  Some weeks later, I checked the hive again.  I found that the combs of brood that were separated from the main body of the brood nest had been chilled and were dead.  The cool weather had caused the colony to reduce the area of brood it covered in order to conserve heat and the brood that was separated from the main nest, even if only partially so, had been abandoned.

Such chilling of brood can occasionally happen with other sorts of hive in cold weather,  but the weather that had caused the problem was cool, not cold.  I was surprised and disappointed that temperature control had again been a problem.  Especially after all I had done to enable the bees to maintain an even and acceptable hive climate.

I thought about this for some time and, eventually, came to the conclusion that a long, relatively shallow, horizontal hive tries to reconcile essentially irreconcilable concepts.  In simple terms,  in the absence of outside interference, hot air rises, it does not move horizontally.   Bees have evolved for millions of years in vertical hollows inside trees.  As a result, they are perfectly adept at coping with the fact that warmth rises and their ventilation strategies will all be based on the physics of natural convention.  Sure, a degree of lateral air movement takes place when a bee colony ventilates its home, but this is minimal in comparison with the vertical element of the air movement.  While it may not be the case in shorter hives, in a long horizontal hive, the opposite is true, the horizontal element dominates.

I could, of course, go back to fiddling with the design and operation of horizontal hives, maybe revisiting closed floors or changing the size of entrance holes in accordance with the weather – larger when hot, smaller when cold.  But this would be to introduce more intervention when my path has been to find a way to interfere less.  Maybe the bees should be allowed to build combs exactly how they please; in circumstances where I have seen this, the combs run lengthwise or diagonally within the hive.  Maybe this is how bees cope in nature with ventilating a long horizontal cavity; the end of each comb abuts the entrance and the combs run in parallel away from the flight hole.   Perhaps there is a format of horizontal hive waiting to be designed that allows for this and, hence, allows for a natural control of hive ventilation.  Maybe a combination of deeper combs and a hive that is less long provides an answer.

But that is for others.   For me, for the present at least, there seems an easier way: give in to the laws of physics and the long evolved behaviour of bees in natural conditions and revert to vertical hives.  This is what I have now done.   All of my hives are now Warrés.

You may also be interested in the article ‘Hives for Bees: seeking balance’, published here.

Gareth, West Oxfordshire, 2012