Top Bar Hives, warts and all

This article first appeared in BBKA News, January 2020.

Background

Over the 9 years I’ve been using horizontal TBHs (HTBHs), I’ve seen many experiments in design and use. This article is intended to help those considering one find their way through conflicting advice.

Some early HTBH guides essentially promoted a gentle style of conventional beekeeping in an odd shaped hive which was regularly manipulated. Since then, enthusiasts in the UK have consistently found that allowing local bees to largely run the well-insulated non-framed hive, which is not treated with miticides and only opened occasionally, makes varroa a non-issue.

This survival rate graph indicates this ‘natural’ or low-intervention approach creates colonies at least as resilient as the more intensively ‘farmed’ bees. (Though BBKA surveys ignore colonies under 5 frames going into winter.)

Allowing the bees themselves to determine how the colony is run, and taking a ‘survival of the fittest’ (Darwinian) aproach, I do not replace queens. With six hives, I view a colony failure as simply weeding out the weak and an opportunity to restock with a swarm from a stronger strain. I do not merge weak colonies as there is no way to tell which queen is fitter.

Why choose a horizontal TBH?

Trade-offs

If you want to try a ‘natural beekeeping’ approach, there are several hive types you could consider. HTBHs can be relatively inexpensive, simple to maintain, and favour a low-intervention style.

Unlike Warré hives, HTBHs ideally require some degree of comb management in spring. For the beginner, this may provide a very useful and positive training experience.

They feature simplicity (fewer tools and accessories, no boxes to store), and no foundation: the comb is pure uncontaminated beeswax of known provenance, and allows the bees to decide the optimum cell-size mix. HTBHs’ shape retains heat better than the high surface area, high volume Nationals. Additional equipment is simple and low cost (no chemicals needed).

There is less disturbance to the bees when taking honey, because the nest is not exposed. This, and the low intervention regime, means the bees are less defensive, so smoke is rarely necessary.

You only need to lift one comb at a time (~3kg). However, the fragile combs can not be handled as casually as frames.

A downside of HTBHs is size. Two Warrés can fit in the footprint of one HTBH. However, their wide, splayed feet make them pretty immune to being knocked over by animals; they are robust for remote locations and they are unlikely to be stolen.

Variants of horizontal Top Bar Hives

Several commercial models are available. My advice is to avoid flat roofs (maintenance issues, less insulated). Self-built ones allow a no-compromise design with exactly the features you want; the cheapest I know of cost £90, using scrap wood. I confess I bought mine, then later retrofitted insulation.

Tanzanian HTBHs have vertical side walls and are designed to take frames. These are uncommon in the UK because they are not as warm as Kenyan HTBH (side walls at 30 degrees, more compact, less surface area). One ‘bonus’ feature of the Kenyan TBH is that they seem to be ignored by woodpeckers. I recommend a Kenyan type for use in the UK.

Insulation is important

Once bees are in, modifying these hives is very tricky. Prioritise insulation before they are occupied – walls at least 25mm thick and plenty of top insulation. Cedar is best (40% better insulator, doesn’t rot easily, much lighter than most woods). Pine doesn’t last as well, and warps.

Although bees are often kept in horizontal tubes in hot countries, in our climate deep HTBHs are best suited to bees’ air / heat flow control, allowing warmth to be retained at the top of combs. In a standard HTBH there is no space (i.e. supers) above the brood comb sucking away heat.

TBH design features (click to enlarge)

Warmth matters because large draughty volumes with open mesh floors hinder parasite control behaviours – the bees have to spend too much effort regulating temperature. Being cold blooded, bees are vulnerable to fungi, and the best way to avoid mould is to avoid condensation on cold spots in a hive’s humid atmosphere.

Design considerations

Viewing windows: A side window is only a marginal extra cost. Try and make one, you won’t regret it.

Entrances can be at the ends or sides. My experience is end entrances encourage more orderly comb building along bars. You want two sets of three round entrance holes (at opposite ends of the hive) which can be blocked with corks; each colony needs one set of entrances. Two sets allows flexibility e.g. to split or merge two colonies in one hive. Entrance tunnels probably deter wasps a bit, but add complexity and make fitting mouse guards tricky. I suspect they make ventilating the hive harder work for the bees too. A landing board makes observing the bees easier.

Edit: after the article was published it struck me that end entrances force the bees to build comb “warm way”, with the comb parallel to the entrance. Side entrances mean the comb is “cold way” (edge on to the entrances, so draughts can blow straight in). I have heard that comb in wild British nests is always built cold way – evidently the bees prefer this, but I prioritise getting the comb built along the bars and not bridging, or the hive becomes un-openable; and this requires more management if the entrances are in the side.

Hive length: HTBHs tend to be 3′ 6” or 4 feet long. Both work, but long ones with legs attached can be just too large to fit in a car. Assume you will have to move it one day and consider how you would remove the legs while bees are in occupation. 3 feet is too short; the hive will get crowded.

‘Eco floors’ are not needed. These are populated with book scorpions or Stratiolelaps scimitus mites, which predate upon varroa. However, these floors add complexity and thus potential problems, like providing a harbour for Small Hive Beetle. In wild nests, bees only permit floor detritus until the comb gets to within an inch of the floor. Incidentally, miticides kill these beneficial creatures.

Mesh floors are important for ventilation in heatwaves, avoiding collapse of the unwired combs; and allow examination of debris that falls through to an inspection tray to reveal what is going on in the brood area. This ventilation should be blocked in winter to retain heat.

Top bar design is crucial. Optimum width to avoid overlapping combs is debated and everyone I asked seems to use slightly different widths! If you prefer uniform bar widths, 38mm throughout seems to work in Britain. Some people (including myself) use 32mm for the core brood area, i.e. the 8 bars nearest the entrance, as we won’t be moving those once the nest is established. Note that nest position is determined by the bees – given the opportunity, they always build it next to the entrance.

I advise you avoid using thin shims to vary width, it gave me problems.

Edit: re-reading this I realise I haven’t explicitly mentioned that bees make honeycombs significantly thicker than brood comb. So if you use the wrong bar width in the brood, or honey areas, the combs can get built out of step with the bars above, and begin bridging bars, which leads to un-openable hives. Which bar width to use in which area is complicated by, for example, the changing size of the brood area over the year; and the fact that drone brood comb is thicker than worker brood comb (because drones are huge). And in my experience the bees always put a comb of drone brood next to my end entrances – obviously considering males the most expendable item in their inventory! – so one thick bar next to an end entrance is a good idea.

Thus, different practitioners have evolved different systems of bar widths – depending on whether they are comfortable with regularly moving bars around, and their bees’ preferred comb width / bee space (which varies between colonies – they don’t mention that in most books do they?!).

Fig.4  Helen Nunn’s elegant angled side bars – craft sticks in slots

Semi frames: Combs deeper than 12” require an edge support to prevent collapse of soft, warm, new honeycomb holding 3kg of stores. Adding edge bars at 30° is tricky, but Helen Nunn cracked this by cutting slots in the bars, with a mitre box and gluing craft sticks in them (figs 4, 5)

Some top bars have triangular guides nailed on. These encourage straight comb, but heavy combs pull the wedges off. Fig. 6 shows better designs.

Fig. 6

Using the hive

Populating your hive

HTBHs should be populated with a local swarm, ideally from a wild colony or non treatment beekeeper which has already proven its ability to survive without human management.

Do not buy bees. A nucleus’ frames do not fit in HTBHs. Commercial queens will interbreed with locals and such colonies can turn nasty after a year, and may die if not treated. The maximum-bees approach of a migratory honey farmer with queens selected for permanent superfecundity is counterproductive for static hives, which experience forage breaks. These breaks are actually helpful if they promote brood breaks – which suppress mites. More bees aren’t always better, and may starve if not fed during dearths.

The downside of a swarm is that it may be a cast with a virgin queen, and if she fails to mate it may dwindle and die over a couple of months. But if honey is not your priority this is simply an interesting learning experience, and you repopulate next year.

Varroa control

I simply let the bees sort it out. I have not seen any large varroa infestations since I stopped using commercial bees. I no longer monitor mite drop rates.

Counting mites doesn’t actually change anything the bees do! Mite drop levels are only relevant if you see a sudden sustained increase (say 5, 10, 20 in successive weeks). But in my experience colonies from swarms placed in TBHs and allowed to self-regulate will self-limit the varroa, exhibiting a constant low level drop – the bees are grooming them off as they appear. An interesting correlation is: the more varroa resistant a colony is, the cleaner their floor.

Of course, untreated colonies will probably die in 1-2 years…. if you place them in cold boxes, suppress swarming and brood breaks, and feed – basically a recipe for breeding mites. Varroa need brood to breed. Consider: if your hives need to be requeened every year, that is true colony failure.

Comb management – less is more

Any hive will become uninspectable if you never open it, as the bees add brace and bridge comb. But every opening is a risk: damaging the queen, chilling brood, destroying the delicate pheromone balances, and training the bees to recognise you as a threat. So, avoid poking around for no reason. Before opening a hive I always say out loud why I am doing so, to keep focused.

Fig. 7 – a comb knife

To remove a comb, first use a long comb knife (e.g. Thorne product code M5131, Fig. 7) to cut upwards along the edge of combs to remove any brace comb holding it to the edge of the hive. Otherwise when you pull the bar up, the comb may tear off and remain in situ.

If a comb breaks off, leave it in the hive for the bees to rescue brood and stores, then remove 1-2 weeks later.

Interventions

The first and most important intervention you need to do is: twice a week after introducing a swarm to an empty hive, check they are building comb straight along the bars. Firm management is needed until they have 3 or 4 good straight combs. These, and a flat ‘follower board’, can then be used to guide others in less frequent interventions – by moving them apart, the bees will build new comb between the initial straight combs and / or the follower board, and it will be parallel to the existing combs. Some users find their bees build straight without much management; the trick seems to be to give the bees no options, i.e. very clear sharp edges. Some people say wax is needed on the edges.

An effective variation by Helen Nunn is to make the bars narrower and separate them: the bees can’t suspend comb from a gap. Her ceiling is formed by a cheap hessian “Warré cloth” which lies over the bars, with insulation above it (fig. 8).

Fig. 8. The cloth is striped because the bees propolise the bands they can access from below.

In spring the nest can expand to 12 bars or more of brood… but is often hemmed in by a wall of honeycomb on bar 7 or so. Rather than move the honey, the bees feel crowded, and create several small, weak swarms. So, as spring progresses open the hive and move honeycombs away from the nest, replacing them with empty bars. The bees build new brood comb in the gap created. (This is why flat comb straight along bars is important: manipulations are impossible without it.)

To minimise the number of times hives are opened, this is often combined with harvesting honey. If they have spare honey in swarm season take a bar or two of honeycomb when you are making room. Harvest little and often. Leave more honey as your local dearth month approaches – for me that would be June.

Some books still advise you to move honeycombs nearer the brood area in autumn, to avoid winter isolation starvation. No one actually does this and the bees are fine – they’ll reorganise and optimise the stores layout for you.

In winter, an HTBH’s volume can be reduced to conserve heat by moving the follower board(s).

Inspections

Most inspections do not require opening the hive. Hive health can be judged largely by how many bees are flying, whether they are taking pollen in, whether wasps are entering the hive, their temper, hefting, and baseboard / entrance debris (this last gives the clearest indication of disease). Storch’s book At the Hive Entrance from Northern Bee Books has much advice here. Essentially: learn what is normal, to spot deviations.

Once the nest is established, I remove and examine some brood comb just once a year (unless external observations imply disease), in spring, for signs of disease and queen failure. I work along the unguarded honeycomb (remove the end 2 for a working gap, then move others along) until I come to the first comb with brood. I carefully remove and examine this, and the next 2 brood combs. I drape a clean tea towel over the gap to retain heat and scents. I take photos to examine later if something occurs to me; that’s sufficient to tell me if there is a problem. There’s no need to disrupt the entire nest, or see a queen – if brood is present so is she.

If the colony has failed I do a post mortem examination to learn why (usually queen failure), and repopulate from a swarm rather than add a queen from a breeder. I generally have one empty hive and five thriving.

Typical TBH brood comb. Honey is stored at the top, capped brood below and pollen between them. Image courtesy Helen Nunn

After establishing straight combs in the first few weeks, I specifically avoid loosening comb in the brood area. The brace comb here controls airflow and baffles draughts, improving nest insulation in winter, and probably aids nest defence. Several years’ accumulation of such comb is absolutely OK with me, providing the combs are straight along bars. That way if I ever do need to remove them (say, to show a bee inspector) there won’t be a massive comb collapse. Brace comb also supports combs if a hive needs moving.

My HTBH brood comb is very old and dark with cocoon fragments, pollen and antiseptic propolis – the bees accumulate it around the brood nest. Nests which remain unexposed have sterile atmospheres (unlike regularly opened hives – demonstrated by Torben Fischer in Germany). Many beekeepers consider old, black brood comb a valuable asset for a healthy hive; wild nests are full of it. Chemical-free management means the foundation is not accumulating miticides, and our experience indicates there is no link to disease. To restate this, if the hive is healthy, why would you remove something the bees have taken years to create? They do remove comb if they do not like it.

Edit: see also this article on how to do non invasive inspections

Swarm management
By enlarging the nest area in spring and continually taking a little honey, the number of swarms is minimised; I pass surplus ones on to others interested in populating low-intervention hives. Swarms are a natural parasite break and an opportunity to improve the genetics of the colony by open mating with other local survivor colonies, so I don’t try to go against the tide with wing clipping, queen cell crushing or queen includers when the bees feel it is time. Some HTBH users practise pre-emptive splits with the follower board.

Hygienic behaviour

Recent research by Torben Schiffer in Germany shows that many bees express pest control behaviours given the opportunity – i.e. if you don’t continually remove honey so they have to prioritise gathering more! This, and parasite-limiting brood breaks, are why left-alone colonies are so healthy. The better insulated the hive, the more energy they can divert to grooming mites, spreading antiseptic propolis, cleaning the comb and ejecting infested larvae. So, allow draught-excluding brace comb to accumulate, and avoid overly fecund commercial queens.

Honey

You’ll probably get more honey from a framed hive using queen excluders and foundation. Removing combs stimulates the bees to build and forage more, but detracts from other behaviours like varroa control. I take only 1-3 combs when the hive is heavy with stores. I don’t take any honey in a colony’s first year.

If taking honey check there are no brood in the comb, then crush and strain it, which is quite messy; but the taste is rich as it contains lots of pollen. Alternatively, as the combs lack wires, uncrushed cut comb honey is easy to produce.

Feeding

It is worth pausing to consider why you feed. For maximum bees? Static hives in gardens will experience dearths. At this point, if you stimulate laying, and have suppressed swarming, there are too many mouths and you have to feed to avoid starvation… stimulating more laying. And varroa.

Authoritative honey producers insist you need lots of bees to survive winter. But though Nationals with selected queens may indeed need 20kg of stores for a Scottish winter, my local bees adjust laying to match available forage. They shrink to tiny clusters over winter and have used 3-7kg a year over 8 winters. Feeding often diluted their honey with unused flavourless syrup.

I find feeding superfluous, barring emergency feeding of a starving swarm. It is fascinating to see a colony establish in its first year, behaving very frugally, and flourish the next – I am content to wait for a honey surplus.

Syrup feeding with an internal feeder requires a full suit. A top feeder does not provoke stings, but requires a steeply angled roof, or an eke, to provide space for the feeder, and a modified bar (with a blockable hole) to allow bees controlled access.

Conclusions

HTBHs are cheap and simple to use, and ideal for people who want to observe rather than intervene. Although you can do most things with them that you can with a National, allowing the bees to express their natural behaviour in this style of hive means they do most of the work for you – like mite management.

Much of the advice above is somewhat counter to standard training, but I found this low intervention / non treatment system suited me better, and led to healthy and much calmer bees.

I encourage you to experiment with variations in design and management. Discover what works best for your local bees.

Further information

I have always benefited from discussions with other beeks. Seek similar-minded people near you; your BKA may know of local HTBH users, and the Natural Beekeeping Trust has a list of some UK natural beekeeping groups.

Various other resources, such as blogs and videos, are available online but be wary of advice from outside the UK (different bees, climate, pests). Also, exercise caution when reading articles more than a few years old, as knowledge and practises are evolving rapidly.

• YouTube is a useful surce of information: e.g. search for “top bar hive UK”
• Background science can be obtained from: www.naturalbeekeepingtrust.org/the-science-p2
• There are also several other articles on HTBHs on this group blog (which you are reading now): oxnatbees.wordpress.com

Copyright Paul Honigmann

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Commentary on this article

BBKA News asked round for someone to write an article on TBHs to follow up the one by John Haverson on Warré hives.

It surprised me that I ended up writing an article for a national magazine, but researching the subject, I realised all the original, high profile early experimenters seemed to have moved on to other hive types (Warré, cathedral, hollow tree etc). Available books were either out of date, American, or too basic. The problem with American information is that the environment and bees are very, very different there. The books aimed at novices tend to cover the basics, but discuss just one TBH design. But BBKA News is for readers who already know the basics, so the article could be aimed at explaining finer points, and dispelling some misconceptions people may have from using commercial bees in framed hives.

The lack of an active guiding Big Name in the field has encouraged experimentation among natural beekeepers, and this has been a blessing – it has turbocharged trailblazing experimentation among iconoclasts and skeptics.