A large rip in this sheet - perhaps from too many washes? I bought these organic cotton sheets on sale a few years ago. They get softer (and thinner) with every wash. They are my son's favorite though, so something had to be done.
First I hand stitched the rip together.
Then just covered the rip with a patch of fabric. I suppose you could do both sides, but this is the fitted sheet, so the underside won't show.