Bottom Board for Winter - Screened vs. Solid?

Discussion in 'Beekeeping 101' started by Larus, Sep 22, 2011.

  1. Larus

    Larus New Member

    Messages:
    77
    Likes Received:
    0
    Trophy Points:
    0
    I need a second opinion on this issue. I was visiting a fellow beekeeper in my county and talking to him about winter preparations. He said that he has solid bottom boards on all his hives. When I told him I was going to overwinter my bees with a screened bottom board, he said that it would create too much of a cold draft, and that for winter I should switch to a solid bottom board. (BTW: We are located in Wisconsin, so seriously cold winter days can be expected).
    On one hand, I am inclined to follow this man's advice, since he has been keeping bees a lot longer than I have been alive. But on the other hand, I have some doubts about solid bottom boards because:
    a) I have heard several times that air moving through the hive is a good thing, because otherwise the steam from the bees gets trapped, condenses on the inner cover and drips back down on the bees.
    b) I have also heard repeatedly that bees don't need to keep the entire air volume of the hive warm, just their cluster. Therefore, insulation and lack of drafts is not as big an issue as lack of ventilation (see above).
    c) Since warm air rises, the air below the cluster will be equally cold, solid bottom board or not.

    So, I'd like to take a poll on this issue - do you overwinter your bees with a screened or a solid bottom board, and what works better for you?

    Thanks.
     
  2. Iddee

    Iddee New Member

    Messages:
    8,996
    Likes Received:
    0
    Trophy Points:
    0
    There were no screen bottom boards until a few years ago. How many years before that did the bees survive in the north with solid bottoms?
     

  3. Larus

    Larus New Member

    Messages:
    77
    Likes Received:
    0
    Trophy Points:
    0
    Very many years, I am sure. But that doesn't mean that a screened bottom board wouldn't be an improvement, increasing their chances of survival. That's what I'd like to know.
     
  4. Iddee

    Iddee New Member

    Messages:
    8,996
    Likes Received:
    0
    Trophy Points:
    0
    Take the floors out of your bedroom for a winter and see if it makes a difference.
     
  5. Americasbeekeeper

    Americasbeekeeper New Member

    Messages:
    1,126
    Likes Received:
    0
    Trophy Points:
    0
    Ventilation is important as L Langstroth points out in The Hive and the Honey Bee. Screened bottom boards are used in almost every state and Canada. You can slide a solid board under the screeen or block the wind if you are concerned.
    "Take the floors out of your bedroom for a winter and see if it makes a difference." is not a good comparison unless you cling to comb hung from the ceiling where the heat and moisture accumulate. We have light, usually artificial as humans too. Should we put light bulbs in hives?
    People that study bees have monitored the temperatures in the hive for years. It is a radiant heat and there is little convection probably due to the nature of the cluster. The bees will change the density of the cluster to increase ventilation and again to reduce it.
    As far as survival, old beekeepers ways, and what was - Langstroth had ventilation in the base of the original hive and it is hard to teach an old beekeeper new tricks. If there was a right and wrong way all of one will survive and the other perish, but bees adapt to our stupidity quickly.
     
  6. Iddee

    Iddee New Member

    Messages:
    8,996
    Likes Received:
    0
    Trophy Points:
    0
    ""but bees adapt to our stupidity quickly.""

    You said a mouthful there. :D
    The bees do seem to do all right in spite of our "help".
     
  7. gunsmith

    gunsmith New Member

    Messages:
    1,249
    Likes Received:
    0
    Trophy Points:
    0
    Good question Larus.
    I am wondering the same thing myself. I'm a first year beek in northern Ohio, and my thinking is that I'm gonna stick with solid bottoms.
    Both Idee and ABK make good points, but it seems to me that a reduced front entrance-along with upper ventilation-is the way to go. I'm using screened bottoms right now, but I think (my opinion) that they would allow the entrance of too much cold air. Maybe we can compare notes with someone who does overwinter with screened bottom boards in the northern climates.
     
  8. tecumseh

    tecumseh New Member

    Messages:
    6,487
    Likes Received:
    0
    Trophy Points:
    0
    a Laurus snip..
    b) I have also heard repeatedly that bees don't need to keep the entire air volume of the hive warm, just their cluster. Therefore, insulation and lack of drafts is not as big an issue as lack of ventilation (see above).

    tecumseh:
    if you had not place 'drafts' in the above I might have agreed. absolute temperature does make a difference as does any possible wind chill. moving air also moves heat no matter if the heat is internal or external to the cluster.

    how many external hives (ie built external to any structure) have you ever seen make a Wisconsin winter?

    at this point in time (given what is now known about the subject) I am not certain why folks are so 'invested' in screened bottom boards.
     
  9. Hobie

    Hobie New Member

    Messages:
    1,399
    Likes Received:
    0
    Trophy Points:
    0
    I live in an area that gets pretty darn chilly. I have Screen bottom boards, but close them in the winter (put in the "mite drop" board, essentially.) It's not a weather-tight seal, but I call it ventilation. I put in the entrance reducer as well.

    I read an article, in Bee Culture, I think, about a guy experimenting with open bottom hives in northern climes. He was having good success, but I can't bring myself to do it.

    Although, once the snow gets a foot or two deep, it really doesn't matter any more either way!

    One word about insulation: Since bees do not heat the entire interior of the hive, keep in mind that insulation will also hold the COLD in come spring when the outside temperatures are rising and the sun shining. I believe that a wind break has more benefit.
     
  10. Omie

    Omie New Member

    Messages:
    2,845
    Likes Received:
    0
    Trophy Points:
    0
    Everyone has different opinions on open bottom boards (as usual, and not a bad thing!).
    I'm in NY and I am trying out leaving my screen BBs totally open through winter, with small top ventilation openings as well.
    Last winter I had two full hives, one survived nicely, the other died off, so it didn't really tell me much one way or another. This winter I'm doing it again, but will have 3 full hives with open BBs. We shall see what happens this winter.

    But I also use 2" thick foam insulation between the inner and outer covers, so theoretically that should help conserve heat and also prevent condensation from dripping back down onto the bees. I also have slatted racks between the lower brood box and the screen board, so that keeps the lower frames a couple inches up from the actual open screen bottom. Yes, I know- maybe it's a 'fancy-schmancy' setup but I have the equipment so might as well use it to see what happens. I like to think more ventilation is a good thing.

    Going to try to overwinter two 5frame nucs this winter- will put them together in one 10 frame deep with a plastic brood box divider and two entrances, and they'll share a bottom board and cover. Now that should be interesting! I'll probably have a solid bottom board on that one, since I have extras lying around.
     
  11. jim314

    jim314 New Member

    Messages:
    586
    Likes Received:
    0
    Trophy Points:
    0
    I just can't wrap my brain around having an open bottom to the hive when it is 10 degrees outside. My main concern is during the day, at least here in Texas, you will get some radiant heat from the sun that would dissipate at a slower rate if it weren't for the open bottom, keeping the inside of the hive warmer longer. The radiant heat would also warm up the interior of the hive through convection so it stays warmer longer.
    But I've yet to winter a hive, so this may all be wrong. But my three hives will be closed at the bottom with hopefully adequate ventilation at the top this winter.
     
  12. Americasbeekeeper

    Americasbeekeeper New Member

    Messages:
    1,126
    Likes Received:
    0
    Trophy Points:
    0
    Convection is the key with screened bottom boards. Warm air rises, warm rising air displaces cooler air. Cool air is rapidly replaced with an open bottom. Theoretically you could place a hive with a screened bottom board over a black surface and it would be warmer than a sealed hive.
     
  13. Omie

    Omie New Member

    Messages:
    2,845
    Likes Received:
    0
    Trophy Points:
    0
    Lots of things at work with these issues. Warmer bees are more active and eat more during the dead of winter. Cold bees cluster tighter and don't consume as much food. From all I've read, I tend to think way more hives die in the winter of starvation or of dripping condensation than die from being too cold.
     
  14. doehunter

    doehunter New Member

    Messages:
    1
    Likes Received:
    0
    Trophy Points:
    0
    I have colonies both ways (with solid bottom boards and screened bottom boards). I do shut off the bottom of the screened bottom board colonies by sliding a board in the slot beneath the screen (I used the screen bottom board type found in Kelleybees.com catalog). I think the board is 3/8 " or 1/4 " thick board. The screened bottom boards came with a slide in corrugated plastic board, but I have never used them, I opted to go for a real wood slide in board which I cut to size.

    Another local beekeeper states he never shuts off his screened bottom board colonies (says there is no need to). But he averages about 30% dead out colonies each spring. He has about 26 to 30+ colonies spread across 9 different bee yards.

    I may work up the courage to try it one year (not shut off the screen bottom board), but having a relatively small number of colonies, I do not want to risk it.

    You know how the old saying goes, if you have 10 bee keepers in a room, you will get 11 different opinions on the same subject or 11 different answers to the same question.

    I guess I will make the decision when I look into the hives for the last time before I put on the mouse guards and entrance reducers.
     
  15. tecumseh

    tecumseh New Member

    Messages:
    6,487
    Likes Received:
    0
    Trophy Points:
    0
    Omie writes:
    From all I've read, I tend to think way more hives die in the winter of starvation or of dripping condensation than die from being too cold.

    tecumseh:
    at one time more hive perished from fire than any other cause. in a great majority of those case the fire was created by a bee keeper who dropped his smoker or got the fire chamber a bit too hot.

    the european honey bee can survive a lot of cold if it has adequate provisions. the primary variables to consider here is the intensity of the cold, length of cold spell and wind velocity. a shelter belt or shield to turn the wind is a big plus anywhere winters are severe. the net effect of blowing wind (and snow) cannot be overstated.
     
  16. Hobie

    Hobie New Member

    Messages:
    1,399
    Likes Received:
    0
    Trophy Points:
    0
    As the owner of an 1875-era house next to a field, I can vouch for this personally.
     
  17. srvfantexasflood

    srvfantexasflood New Member

    Messages:
    910
    Likes Received:
    0
    Trophy Points:
    0
    Whether it be natural or man made, here on the Great Plains wind breaks are a must. ( You know the song... "Where the wind comes whipping down the plain.") I have screened bottom boards that I slide a mite control board in and use an entrance reducer. The entrance reducer is also meant to keep mice out as well as control the wind. In this area, some use solid bottoms and some use screened bottoms with equal success.