[Louise]

So 10 days ago I put a one-way exit under several honey supers that I was letting the bees clean out. Today I went to take them off and the insides of the boxes were pretty wet and the tops of the frames were moldy.

So it seems like it was acting like a vent box - right? I mean with the bees unable to go up their and keep it warm, the condensation was building. . . I guess I'm still at a bit of a loss. If I build a vent box, what is to stop it from becoming a mold pit? And if I don't, what are they doing with all that moisture as the rainy season in Portland begins?

 

[Michael Bush]

>So 10 days ago I put a one-way exit under several honey supers that I was letting the bees clean out.

10 days is too long to wait. I'd just leave it for 2 or 3.

>Today I went to take them off and the insides of the boxes were pretty wet and the tops of the frames were moldy.

Some of this is your climate. I could leave mine for 10 days and not have a problem.

>So it seems like it was acting like a vent box - right?

No, there was not ventilation at the top. True the moist air was probably going through the bee escape and ending up in the supers, but you NEED a vent box on top of that. If you screen in the openings on an inner cover and put a box on top of the inner cover with some screened vents in that then there is somewhere for the moist air to escape at the top.

>I mean with the bees unable to go up their and keep it warm, the condensation was building. . . I guess I'm still at a bit of a loss. If I build a vent box, what is to stop it from becoming a mold pit?

If the moist air can escape at the top it won't become a mold pit.

>And if I don't, what are they doing with all that moisture as the rainy season in Portland begins?

I don't know enough about rasing bees in your climate to know. But I think ventilation is even more important in a moist climate than it is here and I think it's important here.

 

[Louise]

Thanks Michael. I know you've told me before, but now I can't find it. How many vent holes and what size in a vent box? I'm ready to convert some of my shallow supers to vent boxes. Thanks.

 

[Michael Bush]

I think some of it depends on your climate and some depends on using a Screened Bottom Board or not. If you have a SSB then you probably need a bit less. Mine are usually an inner cover with a couple more holes in it about the size of the original. Sometimes I cut them with a hole saw that goes in my drill that is the size of a mason jar lid. That way I can use it for a feeder. These are covered with #7 or #8 hardware cloth. Then I drill some holes about 1" in diameter on the ends of the vent box, angled slightly up so the water runs out instead of in. I usually do two or three on each end. In your climate you may want three on all four sides.

But if you have a SBB it will make more ventilation. Then just put any kind of outer cover on the top.
http://www.beesource.com/eob/althive/bush/bush6.htm
http://www.beesource.com/eob/althive/bush/bush3.htm

These aren't exactly as I described but they are the general idea.

The vent box in the picture has two holes on each of all four sides. I just cut a piece of 3/16" plywood and glued and nailed it on for a lid.