Haven't had one of these plants myself, but it sounds like there may be a solid ball of hydrophobic peat as the rootball. If so, it's much easier to remove after a soak in a bucket of water so it can accept water again. It make take 30-60 minutes to soak to the inside if it's really hard/solid. Usually the peat will crumble away easily at that point. But sometimes it won't, in which case I might decide it's easier on me and the plant to first cut off the bottom third to half of the root ball. Then remove as much excess peat from the top as possible. Cut a slit from top to bottom on each side of the remaining mass. Repot with some room on the sides as well as putting a little new soil to replace that taken from the top. This should give the plant a good shot at growing some new roots, and help keep the inner ball from drying so fast in the process. When you repot next time, you should be able to remove most of the remaining peat without tearing so many roots. The ones I see in pots in this area are always in shade but a little morning sun might be preferable in PA, IDK...

Late spring is usually the best time to divide JPF, but can be divided in the fall also. A 3G plant from a nursery most likely contains several individual plants, as they are usually grown from tissue culture plugs. In any case, they are easily divided, usimg a sharp knife to sever the connecting rhizomes. Be sure that each division has some roots and a crown or growth point, with some foliage. They prefer a moist, but well drained location and slightly acidic soil. Prepare the planting holes by mixing organic compost or peat moss with the soil. They prefer shade or a partially shaded location. In your Zone, they will tolerate more sunlight, than in the southern US. Best color is developed with a few hours of sun each day. Wait until the soil temperature cools down, usually after frost, to mulch. Mulching now will keep soil warm and promote growth, when they should be preparing to go dormant. You can fertilize in the spring, using a 2-3" layer of compost or a timed release chemical fertilizer at ½ the recommeded rate for perennials. They thrive when supplied with adequate moisture and high humidity. After the first year of growth, you can again divide them in the spring, which is the easiest way to generate more plants! After a few years, you will begin to see sporelings appear all around the area. They may or maynot be an exact replica of the parent plant. In any case, they will be an attractive addition. Good luck and enjoy :-) Rb Here is a link that might be useful: Japanese Painted Fern

Here's a follow-up. I pulled my foxtail fern out of the pot. I dusted as much loose soil from the roots as would easily fall away. I then cut the root ball in half with a pruning saw. It was actually rather easy to cut. I then root-pruned each half until I could them nicely and easily into the center of their respective new pots. They turned out pretty good. Carol

Bagged potting 'soils' ARE peat moss, with a few other ingredients (perlite, vermiculite, for example) added for improved porosity. You do not need to add any more. Ferns can be very challenging to grow inside. Your images are very fuzzy, but this fern looks dead, to me. Or, at the very least, all of the existing fronds seem to be dead. Cutting it all the way to the crown is a good first step. Do you know if it's ever been fertilized? If not, it would be worth while to do so. Potting medium does not have nutrients in it, unless it has been added by the manufacturer. It will be clearly labeled, if so. Even if all of the fronds are deader than a door nail, ferns can regrow all new leaves as long as the root system isn't dead. Indoor ferns do best in a cool, bright room away from all drafts. Keep an eye out for scale insects....which may be part of the problem from the very beginning.