Last spring I started two benches of nucs. One bench had screened Bottom boards, the other solid BB. Five nucs on each bench. Each bench had queens from the same batched of virgins and were the exact same age. Nucs were started with three frames of bees and a one gallon feeder. (Each bench had a failed mated return on the first virgin so those were used as mating nucs the remainder of the season and were not considered in this comparison.) Each nuc was fed one gallon of syrup to start to make up for the foragers that returned to the old hive locations. After the virgin was mated and started laying they were fed one more gallon of 1:1 and a large protein patty. Then they were left to gather natural feed on their own until late summer. They grew from three deep frames to 15, drawing out and filling 12 new frames by late July. Late summer, around the first of August, I was very surprised to see the colonies on the screened BB were quite light and had a higher population of bees in comparison to the colonies on the solid BB. The Screened BB nucs were fed some 2:1 syrup to bring them up to fall weight for overwintering. Both benches were fed protein patties and given a sugar block in mid winter. Upon early spring inspection, the colonies on the solid BB were all in the bottom deep on comb that was dryer(Empty) than I would like to see. But the top deep was solid capped honey that had not been touched. Colonies on the screened BB were residing in the center of both bottom and top deeps with capped honey in both boxs along the sides. Screened BB colonies had a larger volume of bees, although the Solid bottom group had plenty of bees for overwintering. All colonies were just starting to lay upon first spring inspection, and they all were almost exactly at the same stage of brood rearing. Stimulated by light spring flow and day length. Colonies on the solid BB have the bottom single deep to rear brood in now, but would be prime for swarming later with that solid dome of honey overhead. Until the bottom deep is well filled with brood I left them alone. But these colonies will need to have the honey frames broken up above the brood nest soon and frames of empty worker sized cell comb installed in the center so the queen has room to move up an continue laying.. Colonies on the screened BB will likely consumed the honey on the sides of the brood nest and filled both 8 frame deeps with brood and only considered swarming if I neglected to add more boxs in time. Someone mentioned on Beesource they just could not make a honey crop on Screened BBs. I could see why. Not sure what the difference is though. My screened BB are run fully open during the hottest months of the summer, closed with a thin sheet of plywood or fiberglass during winter. I have about 130 overwintered colonies ranging from small mating nucs on 4-5 half sized deep frames up to 10 frame deeps stacked four high. My comparisons were done with colonies of aprox. the same size. The solid bottoms, after overwintering were generally wet and grungy, no matter how large or small the colony. Even though they are no longer than my hive bodies(19 7/8). There is no board to stick out and collect rain so the moisture must be the condensation from the bees that collected overwinter and had no where to go. I had no condensation problems at the top of the hive, but it was obvious it collects on the bottom on a solid board. Colony health and size were still good, the wet bottom board bothered me more than it did them. But the colony location was different than the screened BB or the partially screened ones. Colonies of all sized on fully screened Bottom boards with insert for winter were dryer due to the drainage configuration of the bottom. But the colonies on the partially screened Bottoms, left open all winter were surprisingly in great shape. The bottoms with a drain hole and bottom ventilation overwintered very well and had high populations of bees and adequate honey reserves. The colonies on the partially screened and open BB were shocking to me, because they were left on by mistake. I had forgotten I used them and accidentally left them open all winter. The first year I was horrified to see I had left these nucs so exposed, then saw the nice colonies in the boxs and thought , Boy, I was lucky! The second year I did the same dumb thing, yet again the colonies came out of the winter in great shape. This year I ran five colonies on the partially screened BB and again they came out of the winter in great shape. In comparison to the very wet and grungy solid bottoms and the fully screened bottoms with more bees but less honey, I have concluded they are both a little too extreme in each case. A partially screened solid bottom seems to be a better design for the Pacific Northwest rainy climate. The updraft from the ventilation on the bottom seems to be different than just leaving the front entrance wide open all winter. The bees will try to propolize too large a front entrance, but will never try to propolize the bottom screen. I think a partially screened bottom has the perfect drainage and ventilation without being too drafty. It still pains me to leave it totally open all winter though. But I wont worry about getting the slide in closure tight or thick enough to insulate like I did in the past. I dont have the perfect photos to go along with this post yet. Ill add them as I can get them to give you a visual of what I am talking about. Bottom boards in the photo are after I cleaned them off. I should have taken a photo of the grunge and goo.
Posted on: Thu, 20 Mar 2014 16:01:37 +0000
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