Midwinter chores

I was going to title this post ‘Midwinter madness’ until I realised that there’s nothing I could write about related to beekeeping that could compare with current political events. So, it’s Midwinter chores instead …

We’ve had a week or more of low temperatures with intermittent light snow, freezing rain and bright sunshine. During the latter I’ve escaped to walk in the local hills.

North Fife hills

The North Fife hills – when they’re not filled with the cacophony of shooting parties out after pheasant or partridge – are looking fantastic, with unrestricted views to the Angus Glens, Schiehallion and Ben Lawers.

Of these, Schiehallion has a very distinctive shape (it’s just visible in the centre of the horizon above) 1. Its isolation allowed Nevil Maskelyne to use it in 1774 to calculate the mass of the earth in the appropriately named Schiehallion experiment 2.

This experiment used a combination of physics and mathematics, both of which are well beyond me, but are subjects I’ll return to at the end of the post.

Winter checks

In between these gentle walks I’ve infrequently checked all my colonies.

Many of my hives are fitted with clear perspex crownboards. This allows me to have a quick peek at the position and size of the winter cluster. Here are two examples:

Winter cluster – hive #36

and …

Winter cluster – hive #29

These hives are adjacent to each other in the same apiary. Both are in identical 10-frame Swienty poly brood boxes.

What is notable in the pictures above?

The first is that the crownboard with the mesh-covered central hole has been almost completely filled with propolis. I see this time and time again and am convinced that bees do not appreciate any ventilation over the cluster. I think the oft-seen advice to prop the crownboard up on matchsticks is total nonsense, at least for hives with open mesh floors.

Secondly, there is effectively no condensation on the underside of either crownboard. In the absence of ventilation – though both have my homemade open mesh floors – this is because they are both very well-insulated.

Insulation

Both crownboards are topped with a 5 cm thick block of Kingspan insulation. This is an integral part of the crownboard in #36, but just sits on top of #29. This insulation is present all year round, summer and winter.

Here is a picture of the same hives taken in October.

Hive #36 and #29 – note the roofs

Hive #29 has one of my homemade Correx roofs. These cost me about £1.50 each and about 10 minutes to make. They provide negligible insulation as they’re only about 4 mm thick. However, as far as these hives are concerned this is irrelevant as it’s the underlying block of Kingspan that’s doing the insulation.

Perspex crownboard with integrated insulation

The £29 Abelo poly roof on #36, although undoubtedly a whole lot smarter, might add a bit more insulation, but it also made me a whole lot poorer 🙁

Cluster size

The cluster size in hive #36 appears significantly larger than that in hive #29. The area covered by bees under the crownboard is perhaps twice the size.

I don’t read a lot into this.

My notes suggest that hive #36 was a bit stronger towards the end of the summer season. Although it looks as though It’s on brood and a half, the super is actually nadired and was filled with partially capped frames that weren’t ripe enough to extract. I expect they are all now empty. However, the interrupted nature of my 2020 beekeeping meant there’s never been a good opportunity to recover the super.

It’s worth remembering that the bees visible under the crownboard now are not the same bees that were visible in late August, when I last inspected the colony.

These are the long-lived winter bees. Many of them will still be there in early March.

However strong the summer colony was, this is an entirely different population of bees.

Although I’m sure there’s a relationship between summer and winter colony strength, I bet it isn’t linear and I’m sure there are a number of things that can influence it.

For example, consider two identical summer colonies. One is treated with Apivar and the other with Apiguard. In my experience (I used Apiguard for 5 years before moving back to Scotland) the thymol-containing Apiguard inhibits many queens from laying for an extended period. If this occurs when the colony is rearing the winter bees then 3, unless the queen (or colony) compensates 4 the final colony size will be smaller when compared with the Apivar-treated colony 5.

Other things, like the age of the queen or the levels of pathogens, are known (or might be expected) to exert a significant effect on late season brood rearing, further emphasising that there isn’t a simple relationship between summer and winter colony size.

Cluster shape

It’s also worth noting that the orientation and organisation of the cluster will influence its appearance. Consider this picture:

Appearances can be deceptive

The area (or volume if I could have drawn it in 3D) occupied by the cluster of bees in red is identical, but viewed from above, the diameter of the cluster in the top box would be half that of the cluster in the lower box 6.

I’ve noticed before that hives with ample insulation over the crownboard often appear to contain unusually large winter clusters. I’ve always assumed that this is because the bees prefer to orientate themselves into the warmest, most energy-efficient shape to get through the winter.

This shape might need to change to allow access to stores as the winter progresses.

Remember that bees have evolved to occupy often oddly-shaped hollow trees. These might have thick and thin walled regions, or odd draughts, necessitating the reorganisation of the winter cluster to achieve the optimum energy efficiency.

Gaffer tape

The other thing to note from the photographs above is the parlous state of the second crownboard. Both the central mesh (now sealed up) and some of the wooden frame are held together with gaffer tape. This is a near-ubiquitous aspect of my beekeeping, and an essential inclusion in the bee bag.

With the exception of the Correx roofs I use the 3M duct tape sold cheaply in the ‘Middle of Lidl’. It’s great stuff, easy to tear with gloved hands, and pretty strong and sticky.

However, it’s not particularly waterproof. If you want gaffer tape to hold your roofs together for years then the Lidl stuff doesn’t ‘cut the mustard’. Instead use Unibond Waterproof Power Tape, which I’ve written about when discussing building Correx roofs. Mine have withstood the rigours of the Scottish climate for at least 6 years 🙂

Corpses

In discussing the winter bees (above) I wrote ‘many of them will still be there in early March‘.

Many, but not all.

Throughout the winter bees die. If the weather is too cold for flying these corpses simply accumulate on the floor of the hive.

With a strong colony and a prolonged period of cold or wet weather the number of corpses can be so numerous that there’s a danger the hive entrance will be blocked.

If that happens the undertaker bees will not be able to remove them when the weather picks up.

In fact, if that happens, no bees will be able to exit the hive.

Under normal conditions bees do not defecate in the hive. They store it all up during periods of adverse weather and then go on a cleansing flight when the weather improves.

But they cannot do this if the entrance is blocked. This can lead to rapid transmission of pathogens such as Nosema in the colony, with soiling of the frames and inside of the hive.

The L-shaped entrance tunnel of my preferred kewl floors can get blocked with corpses during very prolonged cold or wet periods 7, and I’ve also seen it with reduced width entrances and mouseguards.

Hive entrance cleaning gizmo (patent pending)

To avoid any problems I simply clear any corpses from the entrance using a bent piece of wire every fortnight or so. In my experience there’s no need to do it any more frequently than that.

Stores

Despite the intense cold, the Fife colonies now appear to be rearing brood. I’ve not opened the boxes, and have no intention of doing so just to confirm brood rearing. Instead I’ve infrequently monitored the Varroa trays left underneath the stands in the bee shed 8. These now have faint stripes of biscuit-coloured capping crumbs, clear evidence that there is brood emerging.

And if there’s brood emerging they must have been fed (as developing larvae) on the stored honey from the hive.

Which means that the levels of stores available in the hive to get the colony through the remainder of the winter will be reducing.

I’ve used this ‘no expense spared’ graph before to show how the rate at which stores are consumed increases once brood rearing starts.

Colony weight in early spring

Don’t read too much into the labelling on the horizontal axis. The point I’m trying to emphasise is that stores are used much faster once the colony starts rearing brood, not that the rate changes suddenly in mid/late January.

And, if there’s a lot of brood rearing happening over a prolonged period, there’s a possibility that the colony will run out of stores and starve.

This means that it is critical to monitor the weight of the hive in the early months of the year 9.

Weighty matters

The goal is to determine whether the colony has sufficient stores to survive until forage becomes available.

Experienced beekeepers will do this by hefting the hive. This involves gently lifting the back 10 of the hive a centimetre or so and judging it’s weight.

This will then be compared with either (or both) the weight of a similar e.g. poly, cedar, single or double brood, empty hive or the weight of the same hive a week or two earlier.

As you might guess, this is a pretty inexact science 🙁

It really helps if all your hives are standardised … same material (cedar, poly), same number of brood boxes and the same type of roof.

However, the photo of the three hives (above) is pretty typical of my apiaries … different material, different roof and a different number of boxes.

D’oh!

Nevertheless, all I usually do is heft the hives.

As an alternative approach you can use a set of digital luggage scales. These can be used to weigh each side of the hive, again simply lifting it off the stand a centimetre or so until a stable reading is obtained. Add the two readings together and record them in your notebook.

Weighing a hive ...

Weighing a hive …

This method has the advantage that you get an actual number to compare week to week, not some vague recollection of the ‘feeling’ of the colony and what you think it should weigh.

Popeye

But there’s a problem with using the digital luggage scales.

To obtain a reading stable enough to be recorded you need to lift the hive and hold it very steady. At least, that’s what is needed with the scales I purchased.

With luggage this is trivial. You just stand above the bag and lift it with a straight arm and … peep! … you have the weight.

But a hive on a hive stand means that the digital scales are probably already at thigh or hip height. Lifting 20-30 kg a short distance and holding it steady enough with a bent arm is very difficult.

At least it is if you don’t have forearms like Popeye or eat 2000 calories of protein shakes for breakfast before spending the morning doing benchpresses 🙁

Now you’re torquing

Which brings me back to maths and physics.

A comment on a post last season brought the eponymously named Fisher’s Nectar Detector to my attention. This is a digital torque wrench adapted to read hive weights. They retail for about $130 in the US, but I don’t think they’re sold in the UK 11.

The torque wrench is attached to a short L-shaped steel bracket that is inserted between the brood box and the floor of the hive. The weight is determined by gently applying torque, separating the box by a small distance and then lowering it again.

Although I don’t like the idea of separating the floor and the brood box, I’m intrigued by the advantages this method might offer. I also see no reason why you couldn’t lift the back of the hive from the hive stand, much in the same way as you manually heft a hive.

But the digital wrenches available here (for ~£25-50) record torque (e.g. Newton-metres), not weight. Converting one to the other isn’t difficult if you have a good understanding of basic physics.

I don’t … 🙁

But I think the Professor of Mechanics in the School of Physics might 😉

I’ll keep you posted.


 

Footnotes

  1. As an aside … if you’re interested in the panoramas visible from particular viewpoints (around the globe) I recommend having a look at viewfinderpanoramas.org which has a large number available to download.
  2. He actually calculated the mean density of the earth which he determined was significantly greater than that of Schiehallion. Maskelyne therefore concluded that the centre of the earth was very dense and likely metallic. As if this wasn’t enough, he went on to calculate the densities of the major objects in the solar system.
  3. Which, typically, is when the treatment is used, after removal of the summer honey.
  4. By laying for longer, or increasing her laying rate.
  5. Whilst this would be an interesting experiment to try, the temperatures needed for Apiguard mean it’s ineffective in a typical Scottish autumn so I won’t be doing the study.
  6. And, if my use of πr2 is correct, the area occupied 25% of the lower box.
  7. These floors do not need mouseguards as the L-shaped tunnel prevents the mouse accessing the hive.
  8. See the image a fortnight ago.
  9. If the colony is getting dangerously light before the end of the year, rather than the early months of the following year, it suggests to me that it had insufficient stores at the end of the season.
  10. Or side … the point is the hive stays on the stand and only one side is lifted.
  11. If they are or, even better, if you have one and could comment, please correct me.

33 thoughts on “Midwinter chores

  1. Morris Ostrofsky

    I admit that I am not a physicist. However could the torque wrench be calibrated with known weights in an empty hive? Perhaps making a graph that could be used to determine weight from torque?

    As always thanks for your blog.

    Reply
    1. David Post author

      Hello Morris

      Almost certainly … or you could simply look at the change in the torque needed to raise the hive and use the number as an indicator of the weight. Your way is better though because it provides a more human-readable output and allows hive to hive comparisons.

      Cheers
      David

      Reply
  2. Mr John Macdougall

    How do you clean your perspex cover boards without scratchng and making them more opaque? Soak in washing soda?

    Reply
    1. David Post author

      Hello John

      You need a blunt Stanley knife blade and a window paint scraper … and to have a read of this post. However, it’s worth noting that – over time – they get more and more scratched. Not so bad that you can’t see enough through them though, but don’t expect to take any good close-up photos of the bees. Over time you also care less that they’re starting to look a bit tatty 😉

      Cheers
      David

      Reply
    1. David Post author

      Hi Calum

      It worked well 🙂

      I need to do another couple of batches and get some photographs. However, I’ve got overtaken by some Covid-related events that have changed my priorities for the next month or so, meaning that things will have to wait a bit. Work is also a little shambolic with the new restrictions resulting in some last-minute changes to a variety of things.

      Plus ça change, plus c’est la même chose … as I used to say before Brexit 🙁

      Happy New Year
      David

      Reply
  3. Alan Deeley

    Hi David,
    As far as I can tell in your photos, you have the Perspex quilt on top of the frames and then Kingspan insulation in an eke above that.
    For hive #36 which has no hole in the middle, how would you give the colony fondant?

    Thanks, Alan.

    Reply
    1. David Post author

      Hello Alan

      I’m going to discuss feeding fondant topups later in the winter. However, for hive #36 I’d invert the perspex crownboard, placing the insulation on top and the fondant underneath (in the space provided by the deep sided frame), slap bang on top of the frames. It’s next to the cluster and it stays warmer there than in the cold space above the crownboard.

      Fondant topup

      The insulation is again in contact with the perspex, so condensation isn’t an issue. I’ve done it like this for years and it works very well. The crownboard on #29 (with the hole) is probably a decade old. When I want to feed that colony fondant I simply add an eke underneath the crownboard, providing ‘headspace’ for the fondant block.

      Now there’s no need to write the post on feeding fondant 🙁

      Cheers
      David

      Cheers
      David

      Reply
  4. Greg Monaghan

    David

    Given that we all worry about the stores in the hive during winter I cannot believe that more beekeepers don’t use a more scientific method than hefting.
    I designed and built a set of portable hive scales which give a very accurate reading of the actual total weight of the hive in less than 10 seconds. There is very little effort involved. I have not seen anything like it anywhere else. Perhaps you would like to take a look?

    https://youtu.be/qNFmpqghSfM

    Greg Monaghan

    Reply
    1. David Post author

      Hello Greg

      Very clever. I’m guessing all your hive floors and stands have to be standardised … not in itself a problem of course.

      I’ve seen some homemade scales based upon bathroom-type units but seem to remember that, over time there are issues with the load sensors developing a ‘memory’. I’ve also got (and have used) Arnia hive monitors, but they’re too expensive for normal users.

      You should allow comments/questions on your video as others might want to know more …

      I love a bit of ingenuity 🙂

      Cheers
      David

      Reply
      1. Greg Monaghan

        Thanks. Yes, the stands need to be standardised and need a firm, flat base, such as a paving slab. The scales have a auto-zero function when it is switched on, to avoid load cell memory.
        I’ll turn on comments on YouTube as you suggest.

        Reply
  5. David

    On the question of measuring the weight, might a load cell be the answer? These can convert the pressure (caused by the weight on them) into an electrical signal. I’m no expert but when I mentioned to problem to a friend, he said a load cell might be the answer. They are relatively cheap but would require some circuitry to convert the output into a useful value.

    Reply
    1. David Post author

      Hello David

      I think I (incorrectly) used the load sensors when replying to Greg (above) when I should have said load cell. I think there are issues with some of these and ‘creep’ making accurate measurement of gain and loss of weight an issue if permanently located under a hive. This isn’t a problem with the solution offered by Greg which – as he shows in his video – can be readily re-zeroed, just like taring a set of kitchen scales. The Arnia hive scales I’ve used do not exhibit this creep but are too expensive for the majority of beekeepers.

      Cheers
      David

      Reply
    1. David Post author

      Oops 🙂

      Many thanks Ihor … no joke I’m afraid. This just reflects the current political climate and my poor edukation.

      Now corrected 🙂

      Cheers
      David

      Reply
      1. Ihor Pona

        In school, I was taught by 3 teachers from Scotland in 1959, who made it (physically) very, very clear how important it was to be correct. The colony is now very proud to illustrate our solid learning. 🙂

        Reply
  6. neil munro

    Hi David,
    A happy New Year to you Sir.
    I was interested to see that in both hive 29 and 36 I saw a feature which was also apparent in one of my hives which has not been disturbed much in the back end of ’20. Said feature is the strip of wax between the frame furthest from the cluster and the dummy frame. The only reason I can think of is the same one you make about bees not wanting top ventilation, since this wax reduces the worst avenue for convection downdraft thus reducing the total amount of updraft over the cluster.
    BR
    Neil

    Reply
    1. David Post author

      Hello Neil

      That’s a possibility … however an alternative is the bee space. I think the dummy frame probably does not maintain the proper bee space. The frames are Hoffman but the dummy is homegrown and (inevitably) a bit botched. I guess a test of this would be to move the dummy elsewhere and look to see if they close the gap up.

      Happy New Year
      David

      Reply
  7. Dave Stokes

    Hi David,
    When I first started bee keeping, I went to a talk by Bernhard Mobus at a Steele & Brodie open day at Wormit where he dealt with the matchstick issue. He pointed out that bees quickly propolise a travelling screen but respect an open mesh floor. This would be about 1986 and, to the best of my memory, made no mention of varroa though he did recommend the use of OMFs.
    On the subject of weighing hives, I have a cunning plan. You need a length of angle iron (from an old bed frame or Dexion?) with your luggage scales. You cut off all of one side of your angle iron except for an inch or so at the end. Drill a hole in the iron 10 times the length of the stub from the stub end, and saw off excess and, finally, thread a loop of string or wire through it. I hope you can follow this, if not, I’ll do a sketch for you and send it.
    To use, slide the stub between the floor and the hive so that the long side of the iron is against the side of the hive and use the scales to lift the device by its wire/string. Multiply the weight the weight by 10 – et viola! I think Dr Bodgit should be able to do the skilled craft-work for you.

    Reply
    1. David Post author

      Hello Dave

      Bernhard Möbus would have been unlikely to have discussed much about Varroa in ’86 as it was still spreading across Europe and had yet to reach the UK (which happened in ’92), though it was pretty clear it was likely to arrive in due course. I’m in good company if he also noticed the speed with which they propolise a travel screen. Last winter I purchased some good quality mesh sheets to use as propolis screens as I fancied trying to make some tinctures … your email has reminded me to dig them out and try again.

      Dr. Bodgit is singularly incapable of doing any skilled work at all. He’s a butcher in the workshop … spending his time doing nothing but blaming his tools 😉 I think I understand what you’re suggesting. Have a look at the solution suggested by David V in these comments … his is also a lever-based solution, but rather than use the scales on the non-hive end of the lever he uses the simple pivot to provide a vertical lift to the scales, which themselves are attached directly to the hive.

      If I’ve interpreted your idea incorrectly send me a sketch (and I’ll paste it into here).

      Cheers
      David

      Reply
  8. David V

    I used a bolt to join two stout pieces of wood so they can still pivot. The bolt is at about shoulder height at the top of a vertical piece that bears the weight to the ground. And it is about a foot from the end of a horizontal piece with the luggage scales suspended down to the side of the hive. The other side of the horizontal piece is longer to form a simple lever that allows me to easily lift one side of the hive just off the ground to take a steady reading of the weight.
    The bolt lets me fold both pieces of wood together for storage. It’s not very elegant to lug around but after looking at quite a few options on YouTube I decided to keep it simple.

    Reply
    1. David Post author

      Hello David

      That sounds like a suitable solution to leave in the shed/apiary, but less good if you’ve got multiple apiaries to check. What I love though is the ingenuity … and there’s nothing wrong everything right in keeping it simple 😉

      Thanks for posting your solution.
      David

      Reply
  9. Dave Stokes

    Hi David,
    I don’t know if you saw my reply posted yesterday, though I have noted that you’re rather busy and so your response may take a little while.
    Any road up, I was putting candy on my colonies today and realised that it is possible to use an old fashioned bent style hive tool (as opposed to the modern J-tool). Insert the bent end between the floor and the stand with the long bit sticking up and hook the luggage scales around the top of the tool and pull it horizontally until it just lifts that side of the hive. If one is smart, one could use a queen marker to mark where the 10:1 leverage point is.
    Cheers,
    Dave

    Reply
    1. David Post author

      Hi Dave

      I’m struggling to keep up! Thanks, that makes sense as well … I’m not sure it would work with my floors and stands. The floors have horizontal ‘runners’ on either side which only contact the stand at the corners. The front and back parts of the floors are and inch or two above the hive stand.

      I’m still thinking about this and might try a couple of things in the next week or so when I go and check some more colonies.

      Cheers
      David

      PS You’d need a good quality hive tool for this to work … some of mine appear to be made from folded baked bean cans, though I did snag some lovely replacements in a sale recently 🙂

      Reply
  10. Dave Stokes

    I bought a couple of hive tools for £1 each at the Elgin Autumn lecture several years ago as I could never find one when I want one (even if it was already in my hand). I did wonder about buying more than just the 2, but when added to the one I already have it seems sufficient to always have one to hand. Anyway, they are quite strong enough, as they should be if they’re to be used to prise beehive apart.
    Cheers,
    Dave.

    Reply
    1. David Post author

      Hi Dave

      I buy them in batches of six … usually the el cheapo £2 ones (‘claw hive tool‘) in the Thorne’s sales. However, this year I splashed out and got some much better quality ones of the same design. These are very nice, though perhaps not six and a bit times as nice 😉

      I used to lose them regularly in the long grass around my field margin apiaries. Now I’m a little more organised. I have a bucket of soda in each apiary and keep spares there, but there’s also usually a couple in the bee bag, the passenger seat footwell and rattling (literally) around in the boot 😉

      Cheers
      David

      Reply
  11. Judith Ann Thomas

    Hi David,

    Thank you for your interesting and useful articles.

    On the subject of nadiring, ref:-
    ‘My notes suggest that hive #36 was a bit stronger towards the end of the summer season. Although it looks as though It’s on brood and a half, the super is actually nadired and was filled with partially capped frames that weren’t ripe enough to extract. I expect they are all now empty.’

    Apart from avoiding messing about with the bees just when it is getting cold in order to remove the super it is also tempting to leave a nadired super in place to raise the bees up and give them a bit more warmth and shelter from the weather over winter. It must be naïve in some way or I would hear more about it I’m sure.

    If you left your nadired super in place until the Spring would you expect that your bees may either
    1. start to use the super to rear brood in, or 2. move up in order to access the stores, in which case would wax moth be a risk?
    I would be very interested in the state of your super under #36 when you get to it.

    Thanks.

    Jude

    Reply
    1. David Post author

      Hello Jude

      I expect the super is empty of both bees and stores by now. They probably moved any remaining stores up late in the season. The intention will be to remove it before the colony expands so much that they need the space. Since I treated with Apivar with this super in situ I intend to melt the wax out as there’s a suggestion that one of the amitraz breakdown products is wax-soluble.

      I’m not worried about wax moth in the super … super frames are far less attractive than brood frames and, as the season warms, the box will be busy with bees.

      I know some beekeepers recommend a nadired super to cut down drafts. It’s not something I’ve deliberately ever done for that purpose. It might well be beneficial, but I don’t think it’s necessary … as it is, of the colonies overwintering this season about half are on double brood, a quarter have nadired supers and the rest are in single brood boxes. By choice (and for simplicity) I prefer to overwinter in a single brood box, but events rather got away from me at the end of the season and I didn’t manage to get round the colonies soon enough.

      Cheers
      David

      Reply
  12. Duncan

    My luggage scale (which has not yet visited the apiary) has some clever mechanism which locks the dial at the maximum reading until you reset it. Which means that as long as you don’t jerk when lifting, you get a good reading after you’ve lowered thing luggage / hive back down. Cunning. But just a lucky purchase if I’m honest.

    Reply
    1. David Post author

      Hi Duncan

      I should have been more explicit in my post … the digital one I have goes ‘beep’ when it gets a stable reading. It then holds the reading until you press reset. The difficulty is getting it stable enough to go ‘beep’! I’m dabbling with few ideas at the moment to help my weak arms 😉

      Cheers
      David

      Reply

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