Obviously, Oklahoma cannot be considered the "humid south," but over the years, I've learned that a top cover insulation seems to benefit my bees, so I have been using egg-carton, mattress topping sponges, cut to the size, atop between the inner cover and the telescoping cover on all of my hives, summer and winter.  

Mine are all on screened bottom during summer, but in winter, like now, I have blocked the screened bottom with a wooden piece (I do not use traditional bottom boards at all as the screens are stapled to the deep directly and the entrances are drilled into the deep in two to three different sizes, allowing optimal traffic during the flow and the dearth)--as I do not like using extra/additional equipment.

Closing the screened bottom seems to help spring build up faster according to my limited observations working my bees.  Our fist red maples bloom typically on the first week of February and I'd like to build up mine starting January if the weather permits.  But I do not wrap my hives at all although one unusual year, the polar vortex got spilt over all the way to the south, killing a good number of colonies.  This time I am ready to temporarily bundle them up if I hear such another spill in advance.

Our winter (zone 7b) is relatively mild, allowing at least a few days of cleansing flight per week.  I have not yet experienced any "moisture kill," either, and Nosema is unheard of.  Of course, they do cluster here, too.

             ***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software.  For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html