So, this may be controversial but I have come to the conclusion that the Screened bottom board is not that all effective for mite control and is not worth the extra expense and work to use just as a ventilation aid.
For starters, the mites that fall off are usually ones that are injured, sick or just plain unlucky. These represent a small portion of all of the mites in a hive, of which most are in capped cells any how and are not falling out. So the mechanical mite drop is not that effective.
Then we have the issue of medications. If you plan on using medications, many require the bottom to be closed to that the chemical vapours (like thymol) have a chance to fill the hive and kill the mites. So then you need to use the silly flimsy trays supplied to seal them off. The only "medication" I see benefiting from the sbb (if you can call it medication) is powdered sugar, which requires too many applications because it does not get mites in the cells and then I need to buy all of the sugar.
If you want to go treatment free, the issue in my mind is not mites dropping, but rather mite management by much more proactive ipm methods like drone trapping and brood cycle delaying. Better yet are more hygienic bees that can combat the mites by recognizing and removing infected brood. These are not reliant on natural mite drop.
Finally the issue of ventilation:
While I think ventilation is very important in a hive as it controls moisture management, there are other ways to get ventilation other than a huge gaping hole in the bottom of the hive. Popsicle sticks under the top cover for instance or drilling small ventilation holes or using shims all serve the same purpose just as well. (perhaps maybe not in the humid south or bayou areas but at least where I am in the North East) Where I live in New York I find that the winds and cold winters make it impossible to keep the bottom open in the winter, so I need to put the useless-cheap-plastic-election-sign-material-insert in again which has no insulative value. In the summer when its really hot, you could use rocks to prop the telescoping cover up or invest in slatted racks which can stay in the hive permanently.
...So now I am going back to buying solid bottom boards What says the board?
I agree, and have discontinued making SBB's here. What I've also seen, is the bees covering the SBB's trying to close off the ventilation in the early and mid spring. I think they do better with the solid bottoms. I've been drilling 3/4" holes in the front of the hives at the base of the hand hold for ventilation. I'm seeing that the bees prefer the holes vs. the wide open front board entrance also.
I'm conflicted on this... I switched from solid to screened bb a few years ago... generally do not have to scrape clean the sbb like I had to scrape the solid bb. As I don't treat for mites, or do drone removal, I suspect the sbb are a help for the bees in controlling the mites. I generally close them off in the winter. Now that I have them, I'll keep using them until they need to be replaced, or I notice the bees trying to close them up...that hasn't happened yet.
Regards,
Steven
I've never had a hive try to close up a SBB. In my foggy climate, they're a huge help with ventilation. I'm not sure they're that effective against mites but anything you can do helps.
Yea, I am not sure they are that big of weapon in mite control. I will keep the three I have, but I will build some solid bottoms for this winter. My nucs all have solid attached bottoms with a 7/8 round entrance . I will leave them on for sugar dusting this august
All bee keeping is local. For some parts of the country, they may indeed be the best thing since sliced bread, but my bees struggle to maintain heat in their living area for eight or nine months a year The few 100 degree days we see may be followed by a 45 or fifty degree night. I think in those conditions, staggering a honey super so it has a 1/4 inch opening front and back are far better for ventilation than no floor and draft where the babies are raised. How many times do you hear of someone in the cool part of the country lamenting that their 3 frame colony just won't take off in the spring? DUH!
Beekeeping is a revolving art. People are constantly rethinking and reworking the concepts proven and disproven years ago.
Remember a few years ago when they said to remove the bottom board all together, leave it open. Then they said, bees can't control the humidity as well when evaporating nectar and you would not get as much honey from hives with no bottom board, then they said screen them.
One thing I know for sure, I have never seen a screened bottom board on a tree, a house, a water tank, a combine head, the deck of a boat, etc, and the bees did just fine.
I think they are great. There were two studies that said it reduces the mite count by up to 15%. All I know it that I had very low mite counts compared to other beeks in our club that used solid ones. Perhaps it also has to do with what climate you live in. They are costly, but you can take a solid one, cut out an opening and cover it with mesh. Anyway, no right or wrong just do what works best for your setup.
there was a study in quebec where they discovered that screened bottom boards are effective with mites if the bottom is closed; however, when the bottom is left open it actually significantly increases mites (in that the screen changes the hive to be a more simulating habitat for mites to grow and thrive)
Where I am in TX where it is already hitting 90 in the day and staying 75+ most night, I am using them to aid in ventilation. Using 2x lumber and 1x4s, I actually spend less on a sbb that a solid one. I don't know if they help much with mites though.
After I saw a basket ball size cluster under my BeeMax open bottom board where the mites would fall, I didn't bother with them thereafter. Fads come and go. Best to listen to the girls and do what you find most successful.
I have about 20 SBB's & will probably never go back to solid.
Use them to check mite counts, lower mite levels with powdered sugar, increase ventilation. Only thing we use solid ones for are swarm traps, & catching swarms.
You might want to start a poll on this topic, for people who have used them a few years to vote on.
A fast way to check mite counts is a sugar roll and that requires no real special equipment. As for the powdered sugar, I think the jury is still out on the efficacy. I thought there was a study last year that said it helped but not hugely?
As for ventilation I can see them being a help in a hot climate like California but not here in the north east
Down here in Florida I use only screened bottoms. The girls need all the air they can get most days. We had almost no winter this year and rarely get below 20 degrees ever and usually not below freezing much. I know it helps with mite counts, just dont know how much. But every mite gone is one less to breed. I make all my equipment and it takes a lot less to make a screen bottom than it does a solid one.
Winter was mild this year, so I didn't bother to close mine off. But I suspect a colder winter in Missouri would necessitate closing them off. As hot as it gets in this state in the summer, mine seem to be beneficial to the bees.... yes, all beekeeping is local.
Regards,
Steven
Interesting thread, I have been pondering this for some time and I am going to put some of my hives back on solid boards. My worry is that with that much open space it takes the control of ventilation away from the bees.
I agree. I still have 50 SBB and will continue to use them but started buying solid, mostly because I can use them as feeders and they don't cost any more. http://www.bushfarms.com/beesfeeding.htm#bottom
I'm confused by the Quebec study. How can a closed screened bottom be good for mite control but an open screened bottom be bad? Isn't a closed screened bottom a solid bottom?
I agree with the "beekeeping is local" statements. Here in the hot and humid south I think the sbb is good for the bees. As for taking too much control away from the bees in regards to evaporating nectar down to honey...Thursday I helped my mentor pull honey off of two of his hives...120# off of one hive and 80# off of another one...both hives were double deeps and we left one super on each that wasn't quiet capped off as well as he wanted it to be. We've had a very nice, moist (for a change) spring this year...not an overly dry period of time that might have helped with evaporation. The sbb did not seem to hamper the bees. And, the honey we extracted seemed to have a good moisture %...
My mentor has no problem with mites. His only treatment is powdered sugar dusting.
I use them and build them, but I think top venting is more important here year around. My strongest hives have the crappiest tops, rotted holes, etc. They winter the best too. I'm pretty sure it helps with moisture in the winter. The bottom board doesn't seem to matter as much.
psisk, Michael Bush was talking in another thread about doing a test hive with different debris in the bottom like a tree hive would have. His thinking is that the SHB would live in that rather than going up into the comb.
Let me tell you about debris! if you leave the cloroplast slide in tray in and wax debris falls through the screen but stops at the tray, it creates the perfect place for wax moths to live as the bees cant get in there to defend the area, and I would assume shb would love it also, though I cant say that I have seen them myself in my area
As everything in beekeeping, it depends. If one has a sandwich,screen and solid bottom, the gap needs to be filled ether with sticky (really sticky) board or welcoming pan with oil. In winter, the gap may be closed if necessary. It does not make any sense to me to have a screen and empty board. Sticky board is cheap and easy to use. I normally use the propaganda signs for this.
on the general note, my two permitted beehives are doing very well for couple of years (1 year with me). One of the hives has a steady 50 mites/24h counts and produces a lot of honey; it is 6 mediums tall and actually needed another super. Another hive has 7 mites/24h and never produce any honey at all. Both hives have screen-solid sandwiched bottoms. My observation is that bees are very instrumental in regulating "ventilation" - they block inner cover screened hole (the chimney) if necessary - much more efficient than do something with bottom screen. Sergey
I have both half of my hives are on solidbb and the other half are SBB. Here in washington where it is cold and wet I am finding that the hives with the solidbb are further along than the ones with SBB. Just my two cents.
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