This is quite interesting, and beneficial in a few ways. For one it takes up way less room, I too have had issues when Removing rooted cuttings from the cups with potting mix this should take care of that problem. Thanks for posting Jon this will sure come in handy with the next batch of cuttings.

Yes, Jon, you are right. necessity is the mother of invention and everyone comes up with variations sometimes to suit their needs. I bought cuttings of cold hardy grapes in the fall of 2008 and they were pretty long with nodes far apart. I was told to wait until spring to start the rooting process with any method but I was impatient and wanted to do it in parallel with figs. I could not find long enough bags or glasses. Then it occurred to me that I have an old box of 11' x 8.5" transparency sheets no longer needed for presentations. I made cylindrical pots of different sizes to fig a straight or crooked grape vine cutting (narrow or wide) holding in shape with scotch tape. Closed the bottom with  criss-crossed scotch tape that also provided some holes at the bottom. I made some extra holes on the sides near the bottom. These long cylinders worked fine with perlite for rooting.

Gorgi from my own experience I have to say the #1 thing I like about rooting cuttings in the bag is that out of the 12 I have rooted not one has had the roots stick to the bag unlike the plastic cups. It takes up less room , you can still see root growth through the plastic and when you are red to pot it up you simply fill a pot with the mix make a hole in the center, then cut the side of the plastic bag and bottom hold it gently in your hands put it in the hole and voila. I use a bit more soil than Jon thats probably why its easier for me to do it this way. The ones I had alot of perlite it just falls apart once you cut the plastic bag but again it does not damage the roots. Im happy with the results thanks Jon for posting this.

Paul I have been having the best results with the bags so far the transfer rate from bag to 1-2G pots have been 100% have not lost anything yet. Knock on wood

Lovely pics Jon, thats what I like about the baggie easy to cut the baggie and the roots never stick to the plastic wich wich gives it an excellent trasfer rate with no root damage.