>Paul, have you run a *controlled* trial, comparing colonies with top insulation and no
ventilation, to colonies with top insulation but no ventilation,

Randy, I have not run a scientifically valid controlled trial. I have experimented with top insulation and wrap to determine if they would be of benefit for me here. I put 1" Styrofoam sheets with a 1/2 X 1/2" groove routed in from the center to front edge to give some ventilation assuming that no ventilation would definitely be detrimental, on 50 colonys.  I did the same on another 50 with the addition of a 15# construction felt wrap. Survival was not different from normal. Normal for me is double deeps with 20 frames, solid bottom, inner and telescoping lid. Bottom entrance reduced to 3/8 X 8" and a 1/4" shim at the rear of the telescoping lid. All equipment tight and in good repair, no other ventilation. Hives on stands 12" off the ground tilted forward somewhat. The only loss was queen issues and 1 case of bad dysentery. If there was a decrease in stores consumption I did not notice it.

The down side was dramatically increased mold on the otter frames and boxes of the insulated hives, to me indicating insufficient ventilation. This had the effect of reduced available stores as the girls did not use these frames until I "sun cured" them the following spring. The wrap made no difference from the unwrapped that I could notice. Normally mold is not an issue for me here.

My aim is to have 12 frames of honey going into winter. All-most all make it until March with 1 to 3 frames to spare and I do no additional winter feed. We have hard winters. Usually several weeks around 0 f (-14 c) and several months without rising much above freezing (0 c). Others have noted that the value of wrapping and insulation can vary with the particular winter or location. I believe this is probable. The work and expense of insulating is not trivial. Making sure that they have ample stores has no down side that I can see. They will consume what they need to heat the cluster, have sufficient ventilation to control moisture, and anything left will be used for the spring build-up. You can feed me now or you can feed me latter,.... provided that I survive. It's easier to feed then in the comfort of the fall sun if needed IMHO.

Far eastern WA, 47 north 2100' (640m)

Paul Hosticka
Dayton WA

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