My husband asked for plain curtains for his narrow little office where one wall is a door and a window. He wanted privacy and climate control and nothing fussy (read: black rectangles).
I picked up a bundle of fabric at the creative reuse store for a couple bucks, only to discover it was knit fabric when I got it home to wash. I have had mixed success sewing knits so that the seams do not bubble. I have tried the faux serger stitches on my machine on various projects. I think the deciding factor is how the knit itself behaves with sewing, which I don't know how to predict. This black knit turned out fine. I used a small zig-zag stitch and pressed the hems firmly when I was done.
I clipped the rectangles to the wire and clips my husband got at Ikea. He is pleased, and I am pleased to have a curtain success!