Chilly bees and cleaning the flow frames

Hello Beeks and friends of bees.

I haven’t been on the forum for a while and have been “beek’ing” on my own, with help from locals. However, I’ve realised that at night my bees might be cold and this may be the cause of condensation in the flow frames. So this evening my bees are dressed in a woolly blanket and are sporting a boogie board (a small foam surfboard) on the roof as insulation. I’ll work on a more permanent arrangement, but i like the boogie board thingo. I should tell you that it’s my dog who has offered her blanket to the bees for the night.

There is no AFB or EFB - we’ve tested for same. I live in a warm, climate and this year it’s been dry all year, and cold in the evening.

However, because of the condensation, I have what looks like creeping mould blackness thingo happening throughout the flow frames, which must be cleaned. So i need advice as to how to clean, thoroughly, the frames. I’ve put them in the freezer first and me thinks I will need to dismantle the frames and clean them. Any Advice or tips would be appreciated


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If you want to dismantle them, that would be the most thorough. However, if I was me, I would try first soaking them in hand-hot soapy water with a little dish soap. Then scrub the faces with a softish brush, like a bottle or glass-washing brushing to loosen any mould. Don’t forget to clean out the drainage channel too. If any mould was still visible after rinsing thoroughly, I would soak them in a bucket of 5% household chlorine bleach in water for about 30 minutes. No mould can survive that. Then air dry and store until needed again.

Good luck and please let us know what you end up doing. :wink:

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Dawn, Thank you. I’ll do those things, thought I am not sure how to dismantle them.

Flow has some great videos, which make it look easy. :wink:

I think Flow says 20 minutes on the bleach - might help preserve the plastic if you use a slightly shorter time. :blush:

Anyone try vinegar? Changing the ph for a time might be enough to kill mold.

Vinegar does kill the spores, but doesn’t take care of the ugly black spots like bleach does.

@BeeShack I love your boogie board & dog blankie solution :smile:

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The boogy board will help in summer as well to stop the hot roof from heating the hive. That is the theory behing Warre quilts (with a couple of differences), I use them on my hives all the time.


Do bees like surfing in their hives, then? Joke, joke… :stuck_out_tongue_winking_eye: :joy:

Oh Dawn you’re slipping. :persevere:
I was expecting more of a washboarding reply.


i was waiting for a surfing joke and wasn’t disappointed. :grin:

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So it’s spring here, warm days and cool nights. Yesterday I switched out a couple of the terrible looking flow frames and put in fresh ones and the new ones are full of condensation. What to do?

and… cleaning mould and wax from the flow frames is a nightmare. Any tips or is it just lots of elbow grease.

Hi BeeShack,

I’d love to see photos of your woolly blanket and boogie board hive set up!

At Flow, for cleaning tough residue on the Flow Frames such as mould or wax, we have found best results with a caustic soda soak followed by multiple hot water rinsing (no more than 70°C).

Regarding your condensation issue, I would be very happy to look at photos of this if you are able to send them to

I wonder if the Flow Hive is in an ideal location i.e. does it get enough sun? How is your colony looking, is the brood box established enough to have the Flow Super on yet?

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I use these condensation eliminators: You can find them on Pinterest or in the yard lol. Prop the size of your choice under the hive top parts to create an upper entrance. It creates a “chimney” effect in the hive.


How much are they? Do you have link where to buy? I live in the city now, haven’t seen any for a while.


Hi Bianca,

The weather’s a bit dull today so I’ll wait for some sun to take a pic. As to the caustic soda soak what strength mix do you use?

I’ve taken the flow hive off and put a standard super on - possibly a bit too early so i hope they cope. I’ve reduced the entrance and put the corfute on the upper slot, hopefully, it will help. The mould is quite extensive, I’ve taken all the boxes apart and will clean and repaint them inside and out before they are used again. I’ll have to take the flow frames apart one by one. The hives get the morning sun until about 11am in winter and morning sun in summer. So from that perspective the location is good. We live in inland in a low lying area and it is chilly at night, despite warm days.

I can’t account for the mould: I installed a nuc in Sept 2016, put the flow hive on in December 2018 and have had it on since then. The hive should have had the numbers to keep warm. It may bee [pun intended] that the temperature difference at night has knocked the hive around, and stressed the bees and if so, I wonder how hives survive winter in the northern hemisphere?

Ed, thankyou. i thought that was what the vents were for!!! Yes the chimney effect is possible useful when your’re using the smoker to puff smoke in the entrance!!!

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I’ve had a standard flat roof with vents on and now have a solid piece of ply on the roof, so there is little ventilation. I plan to put the flow hive ceiling and roof on shortly but the roof is sealed so I expect the condensation will travel up to the peaked roof.

I’ve contemplated putting some silica in the roof to absorb moisture. Would you recommend this?

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Why not consider putting a vent at each end of the peaked roof, that way there will be a chimney effect causing an upwards air draft in the hive and that will help with your condensation issue.
Placing a silica bag in the hive makes me wonder if it will actually makes things worse, the bag will soak up the moisture from the air but what happens when it become saturated with water??

I have a question: how strong is the worker population? More importantly, how strong is the worker population in relation to the amount of available space.

A strong colony will circulate the air effective enough so that you don’t get much moisture & mildew buildup.

You don’t want any more supers with frames on the hive than will accommodate the colony.

Go back to basics. A solid floor with a reduced entrance. Enough supers & frames to accommodate the bees. A hive mate with a gap all around it, with a migratory lid.

Hi Pete, That’s a good idea. The flow hive is a very smart design and it’s expensive and i’m not so good with the tools, i’ll try the mat idea first.