howdy Rick,
I was thinking about growing my plants soilless, I refer you to the links below http://www.ponddoc.com/WhatsUpDoc/Plants/Soiless.html
http://bonniesplants.com/how_to/soiless_planting.html (Why do you want to grow them bareroot ?)
to keep dirt out of the pond and to avoid problems of soil going anarobic (Once they start to reproduce it will be so hard to separate the extra plants from the rocks.)
Even if the rocks are big? egg size or larger? (Once the plants start growing their roots will cover the top of the pots so the fish cant remove the dirt.)
I have dirt now in the pond because of them tipping over haven't even though about goldies removing dirt, so far they don't even seem interested. (Whatever you decide , do it now in the fall so you dont disturb the roots in the spring.)
I don't have a lot of neutrients in the water now so I was thinking I should wait till the spring and let the plants use the soil now, undecided as to what's best. (Make sure you get larger pots . I raise pond plants so what I do is use the cheap black plastic pots you buy them in , put a layer of plastic over the holes on the bottom so the dirt doesnt come out and stick your plants in with a little fertilizer.)
Would you not end up with anarobic soil like this? (Make sure you have some fish in that pond or you'll be loaded with Mosquitos.)
Got some goldies in there. (You might also have a problem with all those pretty rocks on the shelf . It looks nice now but a lot of dirt will get stuck around them making it hard to clean . Also as soon as your algae starts growing , they will be covered and if you have Koi , when they get big they'll knock those to the bottom. Rick)
No to Koi, plan on goldies and blue gills. I plan on squirting those rocks when I add water, kind of flushing them out. I plan on using most of them to anchor plants and hide pots. I am going to do an experiment. I have 3 irises:
#1 I'll repot soilless now
#2 repot in the spring soilless and
#3 I'll leave in it's pot with soil. we shall see how they do by summer next year. RexAnne | 
