PSA: That $40 fern from the plant shop off Route 9 in Rhinebeck died in 9 days and I know why
I got a beautiful maidenhair fern on a Tuesday from a little place in Rhinebeck, kept it on my kitchen sill, and watched it turn brown by the next Thursday. The problem was not me, it was the shop, they had it sitting under a drip line in full shade and my bright kitchen cooked it alive. I went back and the owner admitted they mist it 4 times a day in a climate controlled room, which nobody can copy at home. So here is my stance, if a plant shop cannot tell you the exact light and water it had last week, do not buy it. Anyone else get burned by a nursery that keeps stuff in conditions no normal house can match?
Four times a day? That is not a house, that is a greenhouse fogger on a timer. I am not surprised your fern fried in a day or two because a plant raised in that kind of wet air gets spoiled fast. The minute it hits normal room air and a sunny window, it cannot keep up. What gets me is the owner just told you the truth after the fact, like that fixes anything. A shop should tell you what conditions it was raised in before you pay, not after the thing is brown. I would bring it back and ask for my money, because no one can copy a misting schedule like that at home.