I had to give up on the plastic bag method ending up with only rot last winter.
As serendipity would have it, I *mistakenly* stuck one of my cuttings into a pot of vermic, perlite, sphagnum & sand root end up. And guess what happened?
Well this year, I put a couple of cuttings on the slab floor of our sunroom instead of on top of a six-ft. high shelf. It would seem that the temp. of 65deg & below (as opposed to 75+) --has made all the difference.
See pics here:
http://share.shutterfly.com/action/welcome?sid=1QZtWLRw3YsRY&emid=sharshar&linkid=link5&cid=EMsharshar

I have now put the rest root-end up and
4 out of six are happily growing roots & one, which as we know is not uncommon, is starting with leaves as well and has been potted.
So colour me a re-formed Cuttings-Bagger. I rescued a couple of dozen cuttings from under a haybale outside (in the snow!) and they are all in zip locks.
One cutting at a time,

I also found the same issues with temps.  When things hit 71ºF+, the less root growth, the more top growth, and more instances of mold I've seen.

For me, the ideal rooting temp has been between 67ºF-69ºF (room temp, in my house).  Once rootlets form, and I pot in cups, if I can keep it in that same temp range, and ideally around 65-70% humidity, roots seem to be pushing up the side of the cup within a week or two of going in the box.

Thanks Jason.
After getting nowhere last year, it is amazing how fast things move when the conditions are right!-- (for one's area / ambient mold conditions?)

If I can imagine correctly, the cuttings placed on the concrete slab will be horizontal.  Can you explain a little more about the "vertical" part in your post?
I always have been wondering if rooting will be faster or lower when the cutting's natural bottom is placed low (as when planting) or if it is placed vertically high just during rooting process.

I have found that 70F is about the right temp. And I have had some indication that putting the cuttings upside down makes them root better but haven't been able to do a good trial.

Ottawan: we might be on to something.
Since I had a 5% rooting success rate-- better than the zero rate in bags-- last winter: Out of desperation, this year, I stuck a 1/2 dozen cuttings into pots with baggies--vertically.
(see pictures).
Now that you mention it, I have also, due to space constraints, placed my bagged cuttings vertically as well. Possibly just that 6 inches above the floor is enough of a difference to cause greater humidity around the root end?
But I do have damp paper towel in there so...we shall see.

Interesting thoughts.

I bundle up my sticks, and wrap one towel around all at the tip end, leaving the root end exposed.  I inflate my baggie with my breath (I think I learned that from Jon), and prop up with the exposed (root) end up in the air.  But it's not quite vertical.

I hadn't thought about directionality being a potential factor.  I guess I can play with a few of the local cuttings I have to see if it makes a difference for me.

I always had wrapped mine with about 1/2 inch exposed on the rooting end before closing bag blew air and layed horizontally .
Was afraid if i stood it up the exposed rooting end would rest on the bag itself and this would be no good when roots start to develop touching the bottom of bag?

Maybe im misunderstanding whats being done or said here ?

I am pretty sure that when I have read about people burying their cuttings in the ground for the winter, they were placed upside down. Don't ask me for a source or quote: just what I remember from somewhere.

But Jon, that may work only in specific areas where the winter is mild with no perma-frost and where the day time sunshine can warm up the ground surface during the winter (storage time) so the cutting rooting end gets a little warmth for callusing and the cutting other (shooting) end buried low stays cool.
They do the same with grape cuttings.
In real cold areas the cuttings will get frozen dead.

If it works also in the baggie method then the reason may be different than the reason it works in the ground (surface warmth causing callusing). First it has to be proven that keeping the cuttings inverted helps in rooting and then finding botanical explanation later.

Akram,

Believe it or not,
I buried a few cuttings a couple years ago, Nothing fancy just scraped the dirt a few inched and placed the cuttings and covered them.

The following spring I removed them though there weren't any roots but the twigs looked just as good as the day I buried them and actually rooted when I potted them.

I tried it with the VBD/Negronne.

Michigan winters are just as brutal.

So they survived but there was no expediting of roots.

My point was that burial of a single or bunched cuttings with rooting ends up for winter storage is for helping callusing the rooting end from top surface heat in areas with moderate winters. The cuttings may survive in cold areas because of snow coverage or other factors but the top (rooting end) may not callus.
I will try next winter just for fun (if I remember or ....).

Here is one source of info for inverted vertical cuttings:
http://www.bunchgrapes.com/cutting_information.html

It states in the text: "Large quantities of cuttings can also be stored by burying them in pits of sand (to prevent waterlogging) on the north side of a building. They are buried upside down with 6 -18 inches of sand over them, covered with tarps and boards. As spring arrives, some or most of the sand is removed so the bottoms of the cuttings warm and callus in preparation for planting (see callusing)."  unquote.

Akram,
I guess I mis-understood you, Sorry.

But you should try it.
For a fig prone to FMV, The VBD seems to perform well in many ways.