First, when the curtains are hanging up, take a safety pin and pin the bottom up to the length that you want. Just a few safety pins will do, just to get an idea of where it should be. Pin it with the right sides of the fabric together. Take the curtains down and head to your sewing machine.
The trick to this method is in the math. Anyone who knows me, knows I'm mathematically challenged but if I can do it, anyone can do it! Laying the curtain flat on your ironing board measure from the fold to the hem (the curtain should still be pinned at this point). In my example below, it was 7 inches.
We need to take this number and divide it by 2. In my example, that would be 3.5 inches. Remove your safety pins and fold up the bottom of the curtain to be your divided number, again not including the original hem in your measurement. Press and pin as you go along.
Now it's time to sew right along the edge of the finished hem. I like to use my zipper foot - it presses against the original hem nicely.
Once it's sewn, it's time to cut off the excess at the bottom. If you're not sure that you measured correctly now is the time to hang up your curtain and check. But trust me, it will be perfect. I like to cut off the excess leaving about a half inch seam allowance. I just eyeball it.
If you want you can leave it like this, ironing it flat, but I prefer to sew down the seam allowance so there's no chance of the hem rolling up. It's never happened before, but I think it looks a bit neater. It's also helpful if the fabric tends to fray. I just use my regular foot and just sew along the edge of the hem.
That's all there is to it! Honestly, it took me about 30 minutes to hem 2 curtains. And did I mention it works great on jeans too? Yep!
|Closeup of the new hem on the left. Curtains hung on the right.|