Confused Messages at Bee Group

[pargyle]

Ventilation is necessary for respiration & to prevent fungal growth,

My suggestion is that we insulate but not suffocate.

By all means insulate the whole box but ensure there is sufficient ventilation to prevent humidity & damp becoming a killer.

Totally agree ... a mesh floor is more than adequate ventilation - exactly where the bees can manage it ...at the bottom of the hive - anywhere above that.. BIG

 

[charlievictorbravo]

South Devon Convention

I ventured across the mighty Tamar on Saturday and attended the South Devon Convention at Totnes. I did not take verbatim notes at the event but I'm pretty sure of what I heard. There was a speaker there who has recently published an academic paper, who described the relationship between the mortality of Varroa Destructor and the conditions of temperature and humidity. The higher the temperature and relative humidity the less likely the mites are to increase. This was not his research but the work of others that he reported.

His current thinking is that by having a heavily insulated hives, the temperature can be raised and kept high by the bees without using a lot of energy (fuel - winter stores). The high temperature will allow higher relative humidity (NOTE - not dampness) and by relying only on a narrow entrance strip as in an "underfloor entrance", there is sufficient ventilation to allow the OMF to be closed - indeed a form of solid floor was suggested. As much as natural beekeeping has a bad name on this forum, this would appear to be a lot closer to what bees choose naturally in a tree - small entrance hole at the bottom and no holes at the top. If the temperature and humidity keep the number of mites down, maybe the original purpose of the OMF - separating unattached mites from the bees - is no longer relevant.

This is going to take a bit of swallowing - many beekeepers I know have only just got used to the idea of using Open Mesh Floors. However, I was speaking to a successful commercial beekeeper and he says that he is removing OMFs and returning to solid floors on Poly hives because in terms of honey production "the bees seem happier". Not a scientific conclusion by any means but the considered view of a successful beekeeper.

So there you go - Your bees, your hives, your choice.

CVB

As an aside, I asked the lady I was sitting next to what Varroa treatment she used. She looked around to see who might be listening and said that she had not treated her bees for three years and had not lost any colonies. When I asked what the other beekeepers in her association thought about this, she said that she had not told them - she did not think she could withstand the pressure from the old guard if her guilty secret got out!

 

[pargyle]

Very interesting ... the bottom of my poly hives are protected by a 'drawer' at the top of the stand (the same as my long hive) so whilst there is some ventilation through the mesh floor there are no draughts.

I have much the same experience as the post above ... warm/insulated boxes - relatively high temperature and humidity levels in the hives and very little in the way of varroa.

However, I came out as a non-treater... and found that our association chairman was also a non-treater but had not told anyone else !! There's a few more out here than you would think !

It looked an interesting set of speakers ... including our own DerekM !!

 

[Thymallus]

Less than 0.5WK-1

As always, clear as mud.

 

[Thymallus]

sociation chairman was also a non-treater but had not told anyone else !! There's a few more out here than you would think !

You should be able to start an inaugural meeting of the midnight thymollers club.

Don't you think an open mesh floor is just a heat drain? Heat may rise but temperature gradients work in many directions.

 

[For want of a better word]

You should be able to start an inaugural meeting of the midnight thymollers club.
To compliment the already existing midwinter oxallic tricklers club?

Mytten da

 

[enrico]

You should be able to start an inaugural meeting of the midnight thymollers club.
To compliment the already existing midwinter oxallic tricklers club?

Mytten da

And the hive tappers club!!!

 

[wessexmario]

when considering the arguments for ventilation, bottom ventilation has three huge advantages over top ventilation.

- heat rises, even if the floor is completely open and whatever the conditions outside, a bottom ventilated hive will stay much warmer than a top ventilated hive.

- carbon dioxide is heavier than air - with a closed cover and an open floor, the bottom ventilated hive will have a gentle but continuous air change caused by the bees expiring CO2. A top ventilated hive will have CO2 build up in the floor, especially if the entrance is very reduced or blocked by debris/snow/...

- condensation occurs from a temperature difference between air and surface.
Having a closed and insulated cover (and walls) will allow the interior surface temperature to rise to match the internal air temperature, hence reducing condensation. The alternative is to prevent the internal air temperature from getting warmer than the uninsulated interior surfaces, this can be achieved using top ventilation. Both options work to reduce condensation as they help the air temperature match the internal surface temperatures, but the former is at a higher temperature than the latter.

 

[pargyle]

You should be able to start an inaugural meeting of the midnight thymollers club.

Don't you think an open mesh floor is just a heat drain? Heat may rise but temperature gradients work in many directions.

No I don't think it's a heat drain .. I measured the internal temperature at the crown board and about an inch above the mesh floor in my Long Hive on a daily basis for nearly two years and compared these with the maximum and minimum ambient temperatures outside the hive. The gradient between top and bottom of the hive was rarely more than 5 degrees - even in the coldest weather - and there was usually about 3 to 5 degrees difference between the ambient temperature at any time and the temperature just above the mesh floor.

Having said that my hive was sealed at the top, very well insulated and the mesh floor has a 'drawer' under it that protects it from the weather (not sealed by any stretch of the imagination).

I have similar arrangements in my Paynes Poly Hives.

I think the benefits of a mesh floor (in terms of varroa drop, ventilation and the fact that the majority of hive debris falls straight through) outweigh any small effect they have on the hive temperature.

Just been out for a quick look at them .. huge smell of ivy from all the colonies .. although the two I decided to feed yesterday had guzzled 5 litres of 2:1 between them overnight so they got a top up tonight. No thymol though

 

[Itchy]

Interesting measurements Phil

 

[user 6228]

As always, clear as mud.

you asked for preferred conditions i gave you the nest enclosure thermal conductance of 0.5 watts per degree kelvin or centigrade temperature difference between the outside and inside.

 

[pargyle]

Interesting measurements Phil

Nothing conclusive and certainly no scientific basis but what I did observe was that the bees tended to keep the colony at somewhere between 8 and 10 degrees above the ambient temperature when the ambient temperature was anything below about 15 degrees and when the ambient temperature was above 15 degrees they maxed out at about 35 degrees. The humidity in the hive was pretty constant at between 80 - 85%.

Judging by this, my reckoning was that anything that I can do to assist the bees to maintain the conditions they prefer inside the hive has to be a benefit.

Looking through clear crownboards (at all times of the day and night !) I rarely see my bees clustered in the sense that they are in the 'traditional' rugby ball shape - there are nearly always bees active to some extent on the top of the frames - even in the coldest weather. So, I think they must be 'happy' with the situation that my hives provide.

 

[user 6228]

You should be able to start an inaugural meeting of the midnight thymollers club.

Don't you think an open mesh floor is just a heat drain? Heat may rise but temperature gradients work in many directions.

this came up in Totnes...
Its complicated but you can have an open floor as warm as many mm of solid polystyrene. If you can keep the air underneath protected from air currents and pressure differentials, then you get stratification or "stacking" when the floor sides are deep and insulated and without openings.

note the more you close the entrance the deeper the floor sides need to be

 

[Thymallus]

No I don't think it's a heat drain ..
the mesh floor has a 'drawer' under it that protects it from the weather (not sealed by any stretch of the imagination).

I have similar arrangements in my Paynes Poly Hives.

Not surprised you got those results as you are using "floors"!
Not open mesh floors open to the elements. You have a barrier between your open mesh and the outside world. That is a "floor" of sorts in my book, not totally sealed, but no hive is totally sealed.

Try doing the same with no floor present and see what temperatures you get.

 

[Hivemaker.]

Try doing the same with no floor present and see what temperatures you get.

http://www.beekeepingforum.co.uk/showthread.php?t=8117&highlight=snow+melt

 

[For want of a better word]

Nothing conclusive and certainly no scientific basis but what I did observe was that the bees tended to keep the colony at somewhere between 8 and 10 degrees above the ambient temperature when the ambient temperature was anything below about 15 degrees and when the ambient temperature was above 15 degrees they maxed out at about 35 degrees. The humidity in the hive was pretty constant at between 80 - 85%.

Judging by this, my reckoning was that anything that I can do to assist the bees to maintain the conditions they prefer inside the hive has to be a benefit.

Looking through clear crownboards (at all times of the day and night !) I rarely see my bees clustered in the sense that they are in the 'traditional' rugby ball shape - there are nearly always bees active to some extent on the top of the frames - even in the coldest weather. So, I think they must be 'happy' with the situation that my hives provide.

OK a bit off topic... rearing queens ...I keep the incubator at 34 degrees with a Rh of 60 ~70 %....
given that swarm cells are generally place on the bottom for frames in the vortex of cooler air than within the body of the brood nest... is this correct???

Yeghes da

 

[Thymallus]

http://www.beekeepingforum.co.uk/showthread.php?t=8117&highlight=snow+melt

Interesting.

Currently we are getting night time and early morning temps of 4oC. No sign of a cluster in any of my hives first light. Don't you just love those clear crown boards!.

 

[madasafish]

Mine are the same: no clustering yet.. 4-5C overnight. But zero wind - an unusual state of affairs

 

[user 6228]

Mine are the same: no clustering yet.. 4-5C overnight. But zero wind - an unusual state of affairs

if your wintering colony size is sort of average ~1.5Kg and you have a sort of average poly (conductance 1W/ K ) you should only get temperature forced clustering a round -10C in still air overcast sky

 

[pargyle]

Not surprised you got those results as you are using "floors"!
Not open mesh floors open to the elements. You have a barrier between your open mesh and the outside world. That is a "floor" of sorts in my book, not totally sealed, but no hive is totally sealed.

Try doing the same with no floor present and see what temperatures you get.

Well ... Yes and No ...in the LDH I also have 'ventilation' holes around the mesh floor and whilst these are covered in mesh on the inside there is a 65mm drop between the floor and the inspection board so not really a 'floor' as such.

Same with the Polys - open to the elements at the back of the hive below the mesh floor and again a healthy distance between the mesh floor and the inspection board.

Paynes Hive stand showing where the inspection board sits:

https://www.flickr.com/photos/125609724@N03/albums/72157651752848654

Long Deep Hive Floor arrangement:

https://www.flickr.com/photos/99514363@N06/sets/72157634865981506/