Hello Dennis & All,
Dennis said:
I stopped using any upward ventilation on a few hives several years ago.
This year none of my hives have any upward ventilation. I like the results.

Upper ventilation and past beekeeping history in U.S.:

By far the most common top in use in the U.S. is the migratory lid. The
migratory lid is used without an inner cover. No provision for an upper
ventilation is provided. Many hives are wintered in colder areas of the U.S.
by large scale beekeepers without upper ventilation.

Many do remove the migratory top and add an inner cover when wrapping in the
colder sections of the north to provide upper ventilation.

Dr. Furgala was a strong advocate of top ventilation for wintering. He
suggested drilling holes in brood boxes and using corks to plug the holes
when not in use. Marla Spivak still advocates the same as her mentor
advocated.

You can get into a loud discussion among beekeepers at meetings over the
practice of drilling holes in boxes for ventilation.

My own experience:
I have seen hives both with and without upper ventilation with moisture in
the hive through the years.

I have never found moisture in a hive with  a moisture absorbing board above
the cluster to absorb the moisture.

I never used straw above the cluster to absorb moisture myself but have
looked at hives of others years ago and found the cluster to be moisture
free and the straw damp. We use straw on the farm to absorb moisture in
animal barns.

Moisture absorbing boards were in common use for years but rare now it
seems.

Sincerely,
Bob Harrison

::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
-- Visit www.honeybeeworld.com/BEE-L for rules, FAQ and  other info ---
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::