I found this skirt, and REALLY like it. It's comfy, denim, got it cheap BUT I don't like the slit. This slit was above my knee, so it was pretty long. Here is how I filled it in! I used the pant leg of an old pair of hubbys blue jeans.
This is what it looked like, laying on the table. You can see how long the slit is.
1. The first thing I did, was but a piece of denim (from some of hubbys old jeans). I made it in a triangle shape, be sure to make it long enough to attach at least at inch above the top of the slit and below the skirt hem. It's easier to trim extra later, than add more. I laid the slit open so there would be plenty of room for moving. Once finished, my added piece is almost 6" along the hem.
2. I used tailors chalk (it irons off) to draw my finish line. I than used my serger to finish the edge of the insert piece. If you don't have a serger, run a straight stitch and zig zag to finish the edge. Be sure to make it larger that the slit.
3. I than found a matching thread and pinned and topstitched it over the original stitching. I did both rows on each side. Be sure to do across the top, following the orig. stitching.
4. I opened a few inches on each side of the hem, to blend the new hem with the old. I trimmed the hem and stitched it as one.
The finished product.
Here is an inside view to show you how much larger the inserted piece is.