i have polypodium aureum (phlebodium aureum) that seeded in the orchid pot (bark with long-fiber sphag moss) - i left it growing for a couple of years together. just reg care for orchid and occasional mist. then i repotted and pulled it out ... long story - it became a huge plant and started dropping spores everywhere. it's indoors. i i have min 65% humidity even in winter with heat going, but in summer it might go up to 85% (just like outdoors). i had an african mask that i tented for winter to keep it warmer and prevent the drying of the soil. i also had LF sphag as 'mulch' on top - so the spores sprouted in multidude... and in 3 years time the ferns just choked my 'poly'! i had to repot to save it. which i did. the ferns are fine too.
now i bought a bromeliad last december that had i little maidenhair fern sprouting in it (tiny thing) - well, it's still small, but going.
so take a deli container with a lid (clam-shell), lay some moistened LF sphag in it and sprinkle some spores. provided it's in a warn place for a tropical fern and bright indirect light (spring-summer would be best), you should have it going quite easy.
i posted a pic in the database - the whole multi-gen family (that was 1.5 years ago).
