I personally never starch. Even IF I prewash fabric I do not starch. Even fabric from WalMart and Joann's have starch in them. You are washing the starch out and then putting starch back on it. The only time I prewash is if the fabric is black or red. And you can prewash a swatch to see if the fabric is going to run. I also prewash my batiks, but I use a Shout color catcher which works great. I still do not starch the batiks. I know I am going against what many of you do, but I don't want to do more work than I have to.