Re-establishing ferns

[Ben Krysa]

I was wondering if anyone could provide tips to help ferns re-root once the old dirt has been removed. I'm really paranoid about putting any soil from pre potted plants into my vivs. I was thinking of potting them again in my own soil mix and seeing if they take to the mix before then adding the new clean potting matrix directly into my tank. Ferns seem to be the one family of plants that really seem to give me trouble. I really love the look of ferns in woodland setups and I am determined to learn to nurture these seemingly simply plants. Any hints or help would be useful.
Thanks, Ben