# Screened bottom boards out?



## Matt903 (Apr 8, 2013)

Looking at numerous posts the last few weeks, I see that a lot of folks are doing away with screened bottom boards. Are they out as an IPM, good only for extra venelation? Just about everybody in another thread stated if they had to do it over again, they would use solid bottom boards. This includes our moderator. Reasons why?


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## Mr_Clean (Aug 31, 2013)

I think it depends on where you are located. Michael Bush, author of The Practical Beekeeper says he uses screened bottom boards on half of his hives; he is located in Nebraska. I'm in south Florida and have converted to screened bottom boards. The University of Florida's publication on Varroa Mites says screened bottom boards can reduce varroa mite populations as much as 17%; varroa shaken off by bees falls to the ground and those mites often can't find their way back into the hive.


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## Bear Creek Steve (Feb 18, 2009)

I agree with Mr. Clean, it depends on where you are located. I'm at 6,800 feet in CO and run open screened bottom boards year round. Last year's winter losses were 12%.

Steve


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## BeeGhost (May 7, 2011)

I started with SBB and have gone completely to solids. I like the fact that its one less place for ants to get in, there are no bees "lost" and clinging to the bottom screens, including lost virgins. I also don't have to do anything but slap a piece of pre-cut plywood onto a pallet and throw a hive onto it, no cutting and stapling expensive mesh!!

I don't really buy the mite drop study, but I am no expert in scientific studies either. Sure, mites that fall off and drop through the wire are gone from the hive, but almost a 20% reduction in mites due to this?? I don't think so. Ive seen videos of mites transferring from bee to bee, they are pretty nimble for a Frisbee.


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## Jon11 (Mar 29, 2011)

I don't plan on buying any more screened bottom boards. They cost more, rot quicker, and I haven't seen any difference between hives on a solid and hives on a screened bottom board.


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## Rusty Hills Farm (Mar 24, 2010)

I think it depends on where you are and what your reasons are. I have screened bottom boards that are closed on the bottom so that anything that falls thru the screen ends up in a pan of oil. This handles SHB for the hive and can incidentally get some mites too. So it is not primarily for mites or ventilation. It is for SHB control. I think hives do better over closed bottom boards but beetles are a real problem here. This is the best compromise that I have found so far.

JMO

Rusty


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## rwlaw (May 4, 2009)

I tried them on a couple hives for a year. At times in the summer it was driving those hives nuts as there were bees under the screen trying to get in, then the guard bees were plugging the entrance up thinking the hive was getting robbed. Then I come along and try to do an inspection, the wheels would really fall off! 
As I'm in Michigan & really didn't need the ventilation too many times in a summer and they were a bear to clean in the spring, they're now collecting dust.


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## camero7 (Sep 21, 2009)

I have put them in my styro nucs to help with overheating. Solid bottoms for all my other hives. No difference in winter survival.


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## Lauri (Feb 1, 2012)

As I said in my other post, I perfer my inner screened cover to the screened BB. It gives me the ventillation I want when I want it. SBB are easily damaged, the screen is not tough at all. They are great to have when the weather is hot, but when the weather gets cold they are a little bit if a pain, just something you need to fuss with get closed up just right. Bottom boards get grungy, a solid board can be scraped and sanitized more agressivly than a screen. Not to mention the cost difference and ease of construction.

I ran five nucs on one bench on SBB, five right next to it on solid BB. They quickly grew to 8 over 8 deep frames. It was interesting, the screened BB hives were much lighter in weight during the summer. The both appeared highly populated and I didn't get into them to see what was the difference. First thought is the heavy solid bb nucs were not vented enough for fast nectar evaporation, but also consider lots of brood production(Light brood frames) will make a box seem light too. But no matter what the reason, there was a big difference in weight.

When I get into them this spring, If I find any interesting differences, I will report.

Personally, I have not found the SBB make any difference in mite control.

Saying all this, I should mention my hives have done well on SBB and wintered well with slide in insert. I am changing over slowly to solid and will make sure there are no disadvantages. But so far I am seeing none. I never confine hives so ventilation/suffocation is not an issue. My swarm collection box is the only thing to have a fully screened top and bottom. (Not to be confused with a swarm trap) Swarm collection box is how I transport in my truck.


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## Acebird (Mar 17, 2011)

Rusty Hills Farm said:


> I have screened bottom boards that are closed on the bottom so that anything that falls thru the screen ends up in a pan of oil.


I feel the failure of the SBB's is a design flaw. I don't know where I read it but what I read was that the pan or the ground should be at least 2 inches form the screen unless the pan is greased, oiled or sticky. Greased, oiled or sticky keeps the bees from going into the pan and picking up live mites as well as gluing the mite to the pan until it dies. The SBB I got from Betterbee was used in conjunction with a solid BB so the pan was only 3/4 inch away from the screen. So I made my own SBB that is 2.5 inches high and no Solid BB underneath. Because I set my hives on pallets I can put the pan on the pallet and be 2 inches away from the screen. I don't see the need to close off the screen in the winter but if I wanted to I could rout a groove in the sides and slip a board in to close off. This would defeat the effectiveness of the SBB at the time of the year when you don't want to defeat it's effectiveness. So I guess I would also say some of the negatives that people say about the SBB is due to how they are used.


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## Mike Gillmore (Feb 25, 2006)

I have SBB's on all my hives. I built them all from scrap lumber with an investment of $2.80 per hive for the hardware cloth, plus a little paint. (Note: If I had hundreds of hives I might look at this differently, but with a dozen or so hives I find it relaxing work) 

I build mine with a 3/4" opening for the tray. This allows plenty of room to insert an OA vaporizer on the tray, if one would decide to vaporize their colonies with OA. It keeps the hot pan a couple of inches under the bees and could be done on the opposite side of the entrance. An oiled tray would allow you to analyze mite fall after treatments. Summer time the tray is out for increased ventilation, in winter the tray is inserted and the 3/4" opening can be closed off to restrict drafts or a chimney effect in the hive.

As an IPM measure by itself I feel a SBB is pretty much worthless. I've experimented with untreated colonies using SBB's and the benefit of mites falling through the screen was ineffective - the colonies still crashed from mite overload. If OA Vapor was removed from the equation there would be no need for them as far as I'm concerned. There are other ways to increase hive ventilation if necessary.


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## David LaFerney (Jan 14, 2009)

When used in conjunction with robber screens they help to obfuscate where the real entrance is for robbers even more. Also for what it is worth you can't do mite drop counts without them. On the other hand shb go right through #8 hardware cloth. Although I don't think that trying to keep them out is an effective control.


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## gone2seed (Sep 18, 2011)

I am currently changing back to solid bottoms.Swarms hived in sbb hives often leave and queens hate sbb's and tend to stay in the honey supers.That said,I like the best of both worlds and will keep sbb's on one hive at each end of the row(2 rows so a total of four).That way I an still keep an eye on the mites.


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## Acebird (Mar 17, 2011)

Mike Gillmore said:


> As an IPM measure by itself I feel a SBB is pretty much worthless.


IMO, I think you have made it worthless by slipping in the tray and closing it off. You now have a solid bottom board at a time when you need the SBB the most.


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## Mike Gillmore (Feb 25, 2006)

The hives crashed before the tray was inserted for the winter. I'm sure plenty of mites fell through the screen, but it wasn't enough to keep up with the explosion of mites that occurred in the brood nest. 

Sister queens were in other colonies which were treated and they came out strong the following spring. That was my local experience with treatment free, and it won't happen again.


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## Acebird (Mar 17, 2011)

Mike Gillmore said:


> Sister queens were in other colonies which were treated and they came out strong the following spring. That was my local experience with treatment free, and it won't happen again.


Let me know if any crash in five years with treatment.


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## scorpionmain (Apr 17, 2012)

I gave up on screened in favor of solids.

Seemed the Queens didn't want to move down into the bottom box.
I am guessing they didn't like the light. 

Bees would get stuck under the hive.

Had a kill with the use of the oil tray.

I am over them.


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## Mike Gillmore (Feb 25, 2006)

Acebird said:


> Let me know if any crash in five years with treatment.


Sure they do, but 100% losses are unacceptable to me when I have an option to make it 20%.


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## Vance G (Jan 6, 2011)

Strong established colonies may be able to tolerate or winter on SBB's but I would bet a big percentage of the new beekeepers who have colonies that will not build up or thrive are because of that gaping pneumonia hole in the bottom keeping them from heating enough brood to expand. My bees stay wrapped until It is time to manipulate for swarm control and splits and nucs are wrapped til it is hot out. These are tropical insects and they only want one, fairly small, hole in the nesting cavity they choose when swarming.


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## KevinR (Apr 30, 2010)

I think the screen bottom board debate is open to personal preference and location. I have them on most of my hives, including my small nucs. I find that I have less SHB problems with the screened bottoms. I'm assuming the larva fall out, vs a solid bottom where they collect into a heaving mass of nastiness. I can't say on the mite front, since I've never really bothered to do a mite count. I don't actively treat for them.

I do have some design changes that I'm going to incorporate this year, but I don't feel/see any differences in build up for a sbb vs a solid bottom in my area. However, I tend to only have a few weeks of could weather. Most of the rest of the time it's at or above freezing in the winter months.


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## Acebird (Mar 17, 2011)

Mike Gillmore said:


> Sure they do, but 100% losses are unacceptable to me when I have an option to make it 20%.


Well, keep track and let us know that's all.


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## Mike Gillmore (Feb 25, 2006)

Acebird said:


> Well, keep track and let us know that's all.


I just did. Between 10%-30% losses is what I usually see with my treated hives. Untreated hives - 100% losses. I think it has a lot to do with regional pressure. There are beekeepers everywhere here bringing in hundreds of packages every spring, and it's a mite breeding factory. The poor girls don't stand a chance.


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## grozzie2 (Jun 3, 2011)

We started with screened bottoms, then I bought solid bottoms when I started hiving swarms, just to keep equipment costs down. For the second winter I had 3 on each, screened and solid. What I noticed in the spring, all 3 solid bottom hives, had a nest in the lower box when I first opened them. All 3 on screened bottoms, had an empty bottom box.

Kind of a waste of a box, and 10 frames of comb, if the bees wont use it. For any more, we'll buy solid bottoms, the initial investment is cheaper, and, it doesn't end up with an empty box of comb under the nest.


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## Mike Gillmore (Feb 25, 2006)

grozzie2 said:


> all 3 solid bottom hives, had a nest in the lower box when I first opened them. All 3 on screened bottoms, had an empty bottom box.


That's an interesting observation. I'm curious about the other boxes on each set up. 

The Solid Bottom hives had their brood nest in the bottom box. What was in the box above them, empty comb or stores? Just wondering if they moved down as they consumed stores, or if they used less and were still in the bottom box with stores still above.

Likewise, on the Screened Bottom hives what did you find in the upper box? 
Was the tray in or out for the winter?


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## grozzie2 (Jun 3, 2011)

In our case, this spring, here are the details. All of them were nest in the bottom, with honey above, in the fall.

3 screened bottom hives, all spent the winter with trays inserted. In the spring, all were in the top box, bottom box was empty comb, and they were not touching it except to walk past from the entrance up to the next. Supers went on early because we had a warm spring, and abundant flow from the maples. All 3 went to work filling a drawn super (above an excluder) while the maples were flowing, and none of them made any effort to move down into the bottom box with 10 frames of drawn comb. All of these contain the same lineage, australian queens with NZ packages 3 years ago, and open mated local mutts from then on. I know that going into the second winter, queens were at least grand-daughters of the originals, possibly farther removed.

For the 3 on solid bottoms, one was a traditional double deep, top box honey, bottom box nest and honey in the fall. In the spring, bottom box was a nest, top box was empty drawn comb, same lineage as above. They started filling it when the maples bloomed. The second one, slightly non traditional form factor, it was a 3 high of 5 frame boxes, also of the same lineage. In the fall, two upper boxes were honey, small nest in the bottom box. When I opened it in the spring, nest was in the bottom box, and 2 frames of brood in the middle box, the rest empty frames. Top box had 3 empty drawn frames, and 2 frames of honey still on the edges.

The third one, was the most interesting, traditional double deep, 10 frame gear. I had declared it 'died' already in November, no sign of bees coming and going on any warm days, when the other hives were busy. In January, when we put sugar on inner covers, we didn't bother opening that one, it was dead anyways. In early march, when I was checking sugar on the others, I decided to tear that one down, see what happened, and get comb frames to use for managing the others. Pulled off the telescoping cover, looked thru the hole in the inner cover, saw no sign of life, so, off came the inner cover. Still saw no sign of life, altho the hive beside it was flying, so I split the boxes and lifted off the second one, very heavy, full of honey still. And that's when they attacked me, standing there with no gear on. There was a small cluster in the bottom box, which still had 3 frames of honey, and they did not like it when I split the boxes.

Another big difference between that hive, and the rest of ours. Our lineage is 'local mutts' that are descendants of the original package queens we got 3 years ago, except that one. We introduced a queen from a local breeder into that hive late last summer. Talking to other folks that got queens from the same line, lots of similar experiences. Didn't want to open them up in the cold/wet part of the winter, but, had mentally written them off due to total lack of activity at the hive thru the warmer days in the winter. Come spring, lo and behold, there were bees in the hives, and very few of them had moved up into the second box, left a box of honey overhead all winter.

We are already seeing similar behaviour from that hive, and it's two daughter nucs this fall. Not much activity at all, when the others are flying like crazy. But this time, I wont be writing them off until they get opened in March, and till then, not going to touch em.


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## scorpionmain (Apr 17, 2012)

grozzie2 said:


> We started with screened bottoms, then I bought solid bottoms when I started hiving swarms, just to keep equipment costs down. For the second winter I had 3 on each, screened and solid. What I noticed in the spring, all 3 solid bottom hives, had a nest in the lower box when I first opened them. All 3 on screened bottoms, had an empty bottom box.
> 
> Kind of a waste of a box, and 10 frames of comb, if the bees wont use it. For any more, we'll buy solid bottoms, the initial investment is cheaper, and, it doesn't end up with an empty box of comb under the nest.


Yeah, this is what I was trying to say earlier in this thread.
The bottom box on my screened hives were ignored by the bees too.
I was thinking, they didn't like the light.


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## Honey Hive Farms (Nov 1, 2012)

We use both, don't really see a huge differences in either. 
SBB with a tray with oil in it also helps to keep the hive beetles down.
Either one is good for us, a strong hive is a strong hive, doesn't matter.
Vent in either case, at least by cracking the lid.
Good luck to you.


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## Acebird (Mar 17, 2011)

scorpionmain said:


> Yeah, this is what I was trying to say earlier in this thread.
> The bottom box on my screened hives were ignored by the bees too.
> I was thinking, they didn't like the light.


It was not full of pollen? That is what I find but I don't call that ignored. I don't call it waste of a box either. What else are you going to do with it? In the spring when the bees can forage you can pull it and or reverse it putting it on top and the bees will most certainly use it.


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## grozzie2 (Jun 3, 2011)

Acebird said:


> It was not full of pollen?


What part of the words 'empty bottom box' are confusing ? In my case, empty was just that, empty drawn comb, completely ignored. And it was emphasized when they moved up thru an excluder to start storing in the super, but, continued to leave the bottom box empty.


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## KevinR (Apr 30, 2010)

I thinking about incorporating oil trap or / DE trap under my screen bottom boards. After I build them a little stronger.. I'll also try playing with the a personal clone of the beetle baffle system. I think between the two, it might be worth trying. In theory, that should cut down on the light issues and minimize any drafts while still having the benefits.

I'm generally more concerned with SHB that mites... At least they have more of an obvious effect on the hive. 

Is it worth it on a large commercial scale? Probably not...


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## Robbin (May 26, 2013)

I've only got 6 hives, all with SBB and most with oil trays. Completely stopped my SHB problem and I've had none of the brood chambers move up to avoid the screened bottom. I keep the trays in place except in the hotest weather. I'm still looking for an alternative as the SBB with trays are expensive. But I would rather pay the money and never have a SHB problem then get a solid BB and have to fight the beetle problme.


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## Michael Bush (Aug 2, 2002)

I only buy solid bottoms now and convert them to feeders:
www.bushfarms.com/beesfeeding.htm

I bought a bunch of SBB when I thought they would help with Varroa. As far as I can see they did not help. I still use them. There is nothing wrong with them other than not living up to expectations and I can't convert them to free feeders.


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## Mike Gillmore (Feb 25, 2006)

grozzie2 said:


> 3 screened bottom hives, all spent the winter with trays inserted. In the spring, all were in the top box, bottom box was empty comb,
> 
> For the 3 on solid bottoms, one was a traditional double deep,... In the spring, bottom box was a nest, top box was empty drawn comb,


If you would have reversed the bottom box on the SBB hive, it sounds like it would have been identical to the solid bottom hive.


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## Rader Sidetrack (Nov 30, 2011)

oops - clicked wrong button!


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## propet12 (Jun 17, 2009)

I use the SBB to do 24 hour natural-mite-drop counts three to four times a year. Can do all my mite counts in minimal time without having to open the hives and take off the honey supers yet another time. SBB are one of the most useful items in my apiary. 

The only time I take the trays out (slide them out halfway actually) is on the hottest days when there is a lot of bearding; I leave them in the rest of the year. Seems very versatile. Best of both worlds. I do find that I must scrape hive debris off of the trays that falls through the screen every 2-3 weeks in the summer to keep the SHB from laying in the debris - but only takes a minute or less per hive. Agree that as IPM is minimally effective - but even a little help is something.

Haven't noticed bees avoiding laying in bottom box because of SBB. Bees will be in the upper box naturally if no stores are above the brood nest no matter what. Backfilling the brood nest in the upper box moves them down into the bottom box. Sometimes have a queen that lays with a lot of empty comb above the brood nest - but that's really unusual - something else is going on. I still use solid bottoms on nucs because mites aren't a big problem in my nucs.

I have friends who leave tray out all year and say that their queens avoid laying in the bottom half of the bottom box. I don't do that so I haven't seen it myself.


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## Michael Bush (Aug 2, 2002)

There are a couple of advantages to SBB, some of which have been covered, like ventilation and easier monitoring of Varroa, but one big advantage IF you treat is that those mites that are only half dead fall off and don't make it back. Treating on solid bottoms leads to resistant mites quicker than treating on SBB according to the research I've seen presented at some bee conferences.


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## Ddawg (Feb 17, 2012)

Like everyone has said their are positives and negatives in SBBs. I am experimenting with both in my location to see which works best for me. But one thing I keep considering using SBB is that when I did my mite drop counts (prior to any treatment) on a problem hive, I had hundreds of mites on my board. With a Solid BB mites fall on board, bees crawl on board, mites get back on bees. With a Screened bottom board mites fall through screen to the ground and get eaten by ants.


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## Acebird (Mar 17, 2011)

Ddawg said:


> With a Solid BB mites fall on board, bees crawl on board, mites get back on bees.


If you slide in a clean tray (close off SBB) the same thing happens. Mites are close enough to jump back on other bees walking the screen. I say don't buy a SBB. Take your solid BB, cut it out and stapple a #8 screen to the top surface. Then elevate the hive 2 inches or just 1 1/2 with 2x4 stock so you can place a standard plastic lunch tray to check mite fall. Unless you have oil, grease or an adhesive on the tray of a standard SBB you essentially have a solid BB in affect.


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## Ddawg (Feb 17, 2012)

Acebird said:


> Unless you have oil, grease or an adhesive on the tray of a standard SBB you essentially have a solid BB in affect.


My Mite boards were home made boards (coated with cooking spray) slid under the hive sitting about 2" below the screen (I use hive stands), so the only way the mites could have gotten on the board was through the screened bottom board.


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## Acebird (Mar 17, 2011)

Ddawg said:


> slid under the hive sitting about 2" below the screen


That is the magic number. Anything over 2 because the board is usually 3/4 think.


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## kevvan (Oct 4, 2011)

I'm aligned with that finding Ddawg. If I am not treating but want to see if there are natural mite drops, I slide a tray in. When I return in the next day or two there are mites on the tray. The premise of the design is the mites fall through and that is what I find. I can't imagine that this is not an advantage.

I recall Medhat Nassar saying at a talk at EAS this year that most scoff at the notion that mites fall of bees. Mites get chewed off bees or other things - but they don't fall off. He had skepticism as to if they were any value add. As is being shared to each his own I guess.


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## Acebird (Mar 17, 2011)

kevvan said:


> I recall Medhat Nassar saying at a talk at EAS this year that most scoff at the notion that mites fall of bees. Mites get chewed off bees or other things - but they don't fall off. He had skepticism as to if they were any value add. As is being shared to each his own I guess.


They have to come off the bee in order to breed in cells don't they so any of them that don't make it potentially lowers the increase by 5 fold. Does it matter if they are chewed, kicked, knocked, fall on their own accord, or what ever?


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