Top Tips For Preparing To Winter Bees

Top Tips For Preparing To Winter Bees

Chris Wray, the Bee Cosy guy with a mission to insulate our bees, is back with his top tips to help keep our bees through the winter. Go Chris, I’m all ears:

Getting a colony of bees through winter can be quite a challenge unless you the take the right precautions and prepare properly. Here are my top tips:-

  1. Make sure you have a viable colony with a good laying queen before the end of autumn. You can often spot a failing colony by the bees –  not flying in good numbers on sunny days  – seeing that they are anxious (walking quickly over their frames) – not bringing in pollen – or if you’ve seen hive weight drop despite good weather and forage . If weak or failing, combine or make the decision early in autumn to re-queen if possible.
  2. Check for stores – do more than just heft the hive – use spring balances to estimate hive weight – deduct 10% for the possible error in this method – deduct the weight of the hive plus drawn comb and say 2kg for the bees! – My colonies consume between 8 and 12 kgs of stores in the winter (end of October to end of March) depending on their size (with a Bee Cosy fitted) so I plan to have at least 12 kgs of stores – ideally 15 kgs – depending on the strength of the colony. In practice, for a strong colony, at the end of October you are aiming for a spring balance to read 15Kg on each side of the hive (remove the roof before you weigh).
  3. Feed 2 kg :1 litre sugar syrup if stores are short – warm weather is best- between 12.5 and 15 degrees depending on the level of sunshine during the day – Don’t overfeed! – They may still be able to bring in stores from Ivy if they need it and some empty cells for winter brood rearing and clustering is better than a brood full of stores.
  4. Varroa treatment – pick a week when the weather is fair – ideally with some sunshine to raise hive temperatures – the later the better as there will be fewer varroa in the reducing winter brood and more will be impacted by the treatment you choose. Do what you can to keep heat in the hive – varroa treatments work better the warmer the hive.
  5. Hive check and prep – take off queen excluders, replace glass crown boards with wooden ones, reduce draughts in and around the hive, check for gaps between floors / brood boxes / supers / roofs – fix mouse guards. I prefer to leave the plastic trays in my OMFs in and reduce air flow through the hive.
  6. Reduce unnecessary space to help your bees keep a good hive temperature – If you have roofs with big empty spaces fill them with paper / carpet / foam – and if you have small colonies where there may be 3 or 4 frames not occupied take empty frames out and replace with blocks of insulating foam cut to size (see photo below).
  7. Check you have your Bee Cosy fitted! – as well as reducing the stores needed in 2 above, it will also help with points 3, 4, 5 and 6.
Insulation Foam In Brood Box
Insulation Foam In Brood Box

Good luck for Winter 2015 – let’s hope it’s kind to our bees!

Thanks Chris. I recommend everyone visiting the Bee Cosy website to learn all about how modern hives compare to trees as a home for the bees and to understand better the insulation requirements of bees.

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Hive Insulation & Bee Cosy

Hive Insulation & The Bee Cosy

September is a crucial time for me in the Apiary. This is my make and break month in terms of getting the bees through the winter and then having honey producing colonies next spring and summer. I had a disastrous winter earlier this year and hence I am doing everything I can to reduce my bee colony losses over the winter.

Chris Wray, inventor of the cutely titled “Bee Cosy” is mentoring me and writing a few guest posts to help readers get their bees through the winter. The modern hive is pretty cold compared to the hollow of a tree. Hive insulation reduces the amount of stores required by bees and increases colony survival rates.   The Bee Cosy is “the world’s first breathable waterproof insulating hive cover”. He’s on a mission to increase bee colony survival rates. I recommend reading every page of his website because it is all interesting and useful.

Bee Cosy
Bee Cosy

I mentioned I had a cunning plan for this winter and this is it. Chris is providing me with mentoring and a couple of Bee Cosies and in return I bought a further couple of Bee Cosies and am providing some publicity.  Let’s hope this works.

In his first guest post, Chris discusses UK winter losses compared with the Bee Cosy losses.  In his next post, he’ll go through a checklist to get everything ready for winter.

Bee Cosy Winter 2014 Losses Of Only 2%

By Chris Wray, Bee Cosy Inventor

The BBKA’s winter survival survey for winter 2014 showed losses across the UK of 14.5% with losses of 15.5% for the North East where most of our Bee Cosy sales have been made.

As for winter 2012 and 2013, we surveyed all Bee Cosy users on the same basis as BBKA – i.e. colonies in place at 31 March. Although our sample is not large as the BBKA, we achieved a fantastic 98% survival rate from all the beekeepers who responded using a total of 40 Bee Cosies.

Bee Cosy Winter Losses 2014 / 15
Bee Cosy Winter Losses 2014 / 15

As you recall, the winter of 2014 was not as bad as forecast. Bad weather was confined to fog and icy roads in December, storms and strong winds in January, and some snow in early February. The Met Office’s statistical summary showed that, across the UK, “the average winter temperature was 0.2 degrees higher than usual for 1981-2010. There were 25% more hours of sunshine than usual, and slightly less than the usual 33 days of air frost ” Despite 2014 being a mild winter, BBKA statistics showed that UK colony losses still increased to 14.5% from 9.6%.

As seen in the graph above, with 3 years of survey results now in, the Bee Cosy does seem to be making a difference. Whilst there may be a small positive bias in these results in that the Bee Cosy may attract a more assiduous beekeeper, there is also an element of negative bias in that beekeepers may be choosing to put Bee Cosies on their weaker hives.

Overall, I believe the results show a good case for the merits of the Bee Cosy.

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  • Bee Cosy website
  • My Apiary – My notes show my preparations for winter. The small swarm has perished due to wasps leaving 3 good colonies. Apiguard treatment finished. Feeding in progress.  Extra roof insulation added.

February In The Apiary

February In The Apiary

Hive Two

Let’s start with the good news.

Hive Two looks healthy.  20 bees flying around at any one time on sunny days and I placed the varroa count board under the hive for 6 days and counted 0 varroa. I suspect that another reason for it’s success is that it is protected from the wind and has an insulated roof. Photos below.

Hive Two - Flying Bees - Feb 2015
Hive Two – Flying Bees – Feb 2015
Hive Two - Varroa Board - 28 Feb 2015
Hive Two – Varroa Board – 28 Feb 2015

Zoom in below – see if you can find any mites:

Hive Two - Varroa Board - Close up
Hive Two – Varroa Board – Close up

This hive has been varroa-free since May 2014. I wrote about this under From 2,000 To 0 Varroa In 8 Months.

Hive Five

I wrote about Hive Five under Colony Post-Mortem. I have now placed old comb on the bonfire and the good frames are currently in the freezer. Conclusions: died of mite overload and cold.

Hive Three

This is the other hive I moved which could also be too exposed to the elements. I saw plenty of flying bees two weeks ago but it has been quieter recently. I counted 6 mites over 6 days on the varroa board which calculates a rough estimate of 50-400 mites and treatment required in 3-5 months.  There was not much debris on the board, see photo below, so I’m worried about Hive Three too.

Hive Three - Varroa Board - 28 Feb 2015 - 6 mites
Hive Three – Varroa Board – 28 Feb 2015 – 6 mites

Hive One

I think there are some bees in Hive One, but only a few. The Queen is five years old. I’m hoping she will supercede. I have yet to place a varroa board underneath. Photo of landing board below. Is the brown stuff dysentery or propolis or mud? And would some dysentery here be OK or bad?

Hive One - Dysentery - Feb 2015
Hive One – Dysentery?? – Feb 2015


It looks like I will have had a terrible winter. The reasons:

  1. In at least one hive, I failed to adequately control the varroa. I need to improve on this.
  2. In the dead hive and the two weak ones, despite good intentions, I have not insulated the roofs and they have porter bee escapes and vented roofs allowing air to flow through and chill the bees. I guess quite a few other new beekeepers have this problem, as this is how the hives arrive. I will use solid crown boards and insulated roofs next winter (but guess it is good to allow ventilation in summer)
  3. Moving the two hives 100m over rough ground would not have helped. I will only move nucs or swarms in the new out-apiary location rather than move full colonies

Hard lessons for someone who was hoping to expand to 6 hives this summer.

I’m also thinking that bee equipment suppliers should include roof insulation as standard and advice on closing off any vents over winter.

Hive Ventilation & Configuration

Hive Ventilation & Configuration

At the start of Autumn, the disagreements start about how warm to make the house.  We compromise at 19.5C which means I’m wandering around in shorts whilst Heidi wears 3 layers of clothes. She sometimes pulls up her hoody but I think that’s just her trying to make a point.  When the mother-in-law is down, she’s “freezing” (I think she has been scarred by Scottish winters), it’s 2 against 1, the thermostat goes up, the problem is exacerbated and I have to protest by wandering around naked.  My protest does not go unnoticed (my daughter says “daddy pants on”) but it is ignored.

So whilst there is some disagreement in our local eco-system there is also disagreement between beekeepers when it comes to hive ventilation.

Preparing Bee Colony For Winter

Before we talk about hive ventilation, there are a number of elements that most beekeeping literature seems to agree on when preparing a hive to successfully over-winter:

  1. A strong colony
  2. Queen-right
  3. Disease free
  4. 20Kg of stores (read: feeding bees for more information)
  5. Low varroa count
  6. Insulation in the roof

My bees are in 14x12s with a super below.

Hive Ventilation

The reason the colony needs good ventilation is to make sure that condensation is not dripping on the bees during the cold, winter months.

There seems to be two schools of thought on hive ventilation and how to configure your hive between autumn and spring. In 2014 in separate issues of the BBKA magazine there were articles by beekeepers advocating both methods. These are described below.

Note: if you have solid floors then top ventilation is required.


In all cases insulation in the roof is deemed a positive, though some beekeepers say it is unnecessary. The rationale for roof insulation is that with no insulation the warm moist air which rises will condense on the cold roof or crown board and drip on to the bees.  Roof insulation reduces this process.

I say insulate the roof (and the walls if you can).

Option A: Top & Bottom Ventilation


  • Open mesh floor (allows the air in)
  • Holes open in the crown board (allow air to flow through)
  • Insulated roof (means the warm air rising does not condense and drip down due to a cold roof)
  • Side vents in the roof (allows the warm, moist air out)

Argument for: A chimney effect allows warm moist air to rise and escape.

Arguments against: Some/quite a lot of beekeepers say that this chills the bees too much and works against the nature of bees who try to propolise top vents.

Based on my experience I would advise against this chimney effect, the bees need to be cosy in winter. Go for bottom ventilation only.

Option B: Bottom Ventilation Only


  • Open mesh floor
  • Solid crown board
  • Insulated roof

Argument for:

  1. This is more similar to how wild bees manage condensation
  2. This method establishes a convection current, warm air rises in the middle and then falls at the sides, when it reaches the bottom some of the moist air is exchanged for dryer air

Argument against: I couldn’t find arguments against.

National Bee Unit (NBU) Advice On Hive Ventilation

The NBU does not go into much detail but does say the following on hive ventilation: “Damp rather than cold kills bees so check hives, especially roofs, to ensure rain is shed away. It is best to ensure that your hives are off the ground on suitable stands. If your apiary site is not vulnerable to windy conditions, and you are using open mesh floors, they can be left with the floor inserts out. If not, or your hives are on solid floors, then you can lift the crown board on two-millimetre laths. Used matchsticks are excellent for this purpose.”

They have also produced a guide on “Preparing your hives for winter” – this link opens the PDF and is worth a read.


  1. Some ventilation is required but not too much
  2. Open mesh floor is enough
  3. I think open mesh floor with top ventilation is too much
  4. If you have solid floors then top ventilation is required

I welcome your thoughts on the above article.

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Postscript: I had a disastrous Winter 2014 (see My Colony Losses). In Autumn 2015, I added roof insulation plus a Bee Cosy. I kept the Open Mesh Floor. Read Top Tips For Preparing To Winter Bees.