If you really love a pair of jeans and you don't want to get rid of them when they get a hole in the knee, or you don't want to spend more money on clothes for a crazy little boy after he tears up his jeans, here's how to fix them.
Step 1: Materials
You will need a sewing machine, thread that is close in color to the denim, scrap denim*, scissors, pins, and an iron.
*Alternative fabrics that work for patching jeans include most bottom weight fabrics such as twill and poplin. Poplin is especially good for patching stretch denim. Do not use light weight cottons such as broadcloth and calico. They are not strong enough and will tear in a short amount of time.
Step 2: Make the Patch
Cut out your patch from the scrap denim. The patch should extend at least 1" beyond the edge of the hole or worn area. Rounding the corners of the patch reduces tension points so the jeans are less likely to tear along the edge of the patch over time.
Step 3: Iron
Turn jeans inside out. Using your iron on a medium high setting, press the area of the hole so there are no wrinkles or puckers.
Step 4: Overcast
Using the zig zag setting on your sewing machine, overcast stitch around the edge of the patch to hold it in place and prevent fraying. Remove pins. Then, turn right side out.
Step 5: Zig Zag
Zig zag stitch around the hole, then fill hole stitching the same direction the exposed white threads are going. Continue zig zag stitching in a spiral pattern around the hole until the patch area is secured.
Step 6: Finished
Now you're done!