Repotting a Boston Fern–what Do I Need to Know to Do This?
My Boston fern appears to be dying. Might this be a root-cramped problem?
Certified GKH Gardening Expert
While Boston ferns typically prefer to be kept a little pot bound, if it is getting difficult to water, especially if the water doesn't seem to be penetrating the soil well, or if you see roots coming from the pot, then it is probably a good time for repotting. In this case, you would go up a couple inches in diameter or two pot sizes. You can also remove any old or dead growth during this time.
Here is an article that you may find helpful: https://www.gardeningknowhow.com/houseplants/hpgen/learn-more-about-repotting-houseplants.htm