Friday, December 11, 2009

Screened Bottom Board & Winter

***Update (10/10)***
Now I close off all my SBB's in mid-October.  I use a bottom entrance and have an (insulated) venting shim/box between the inner cover & telescoping cover all Winter.  This provides passive air flow to allow humidity to escape without condensing in the hive.  Though half of the beeks in the local club keep their SBB's open all Winter I prefer to close mine.  For me it is a issue of brooding up early in Spring.  I open the SBB's up again once the nightly temps are above 60f.

I have a Dadant SBB on Mary.  It comes without a bottom sheet normally used for Varroa counts.  I can close it of with anything made of plastic or wood but I thought I might leave it open all Winter.  Moisture has been a problem with this hive so I want to vent it as much as possible.  Last year saw a puddle of cold water drip down through the hive during Winter.  I did not want to repeat that again. But, it has been a very cold couple of weeks & it looks like it will be a sever Winter.  The bees have been in cluster for almost two weeks now.  Last Winter we had fly days every week or so.  I took a picture from under the SBB of Mary yesterday and found a bunch of dead bees.  That is natural, i think, but concerning.  Since she is down to a single deep her cluster is very close to the bottom edge.

Dead Bees 

I sealed off the SBB this evening after work with a piece of luan.  I'll leave it there for the rest of Winter.  The Vent box is still on the hive so the humidity will continue to dissipate from there.  I have designed a SBB of my own that utilizes a deep tray beneath the screen and some adjustable side vents.  I'll post it when its made, after the New Year.  

Some beeks leave their SBB's open all year some beeks use only solid boards.  I guess I'll be taking the middle road on this issue.  SBB's all year but closed off during Winter.  The timing will be dependent on the weather.  But, I figure the hives will be closed off from December to April.

Myrina still having the Solid BB was left alone.  Both colonies showed signs of activity inside the hives.  As good as she is about her solid board I don't yet know if she'll get a SBB.


immwia said...

I don't know how they manage to stay alive and warm with those little bodies and cold weather. Good luck to you.

Anonymous said...

Do you leave the luan or plastic sheet that is used for catching varroa mites in the SBB during winter. I was considering removing mine, but don't want the bees to freeze it will be 1 degree on Sat.

Polar said...


Well in this case I don't have a varroa counting sheet just a SBB. I did close it off when it got cold though. I used a sheet of luan (1/8 inch plywood). I know people use sign board or anything rigid to close off the bottoms. I'll likely take it off in April. Some beeks leave the SBB open all year but i can't bring myself to do it. PLUS, I will start feeding pollen in a few weeks for brood rearing. I want the bees to be able to access the bottom of the frames for egg laying. Something that is hard for them to do with an open SBB & cold weather.

Anything wood or plastic can be used to close off the bottom.