Okay, I know you will probably think I'm nuts when you read the subject line of this post. But I have been making my own detergent for about two years now and I LOVE it! It saves so much money, cleans as good as the stuff you get in the store and it totally rinses out of your clothes (unlike store-bought detergent) so I don't have to use fabric softeners.
I think I've seen all the ingredients at Kroger, but I chose to order the grated soap from http://www.soapsgonebuy.com/ because I make a big batch that lasts about a year and I don't want to grate all that soap. These instructions are from Mary Hunt (Everyday Cheapskate).
Powdered Laundry Detergent
1 cup grated Fels-Naptha soap
1/2 cup Arm and Hammer Super Washing Soda (not baking soda)
1/2 cup 20 Mule Team Borax
Mix and store in airtight container or bag. For light loads, use 2 tablespoons. For heavy loads, use 3 tablespoons.
Big Batch: To make a large batch, grate 6 bars of Fels-Naptha Soap and then add 3 cups of Super Washing Soda and 3 cups of 20 Mule Team Borax. Mix well and store in covered container.
TIP: Homemade detergent will not make suds in your washer, so don’t be alarmed. Fels-Naptha Soap is a pure soap and typically makes little or no suds in the water. This makes it perfect for use in the new HE washers as well as traditional washers. You will also notice the need to either reduce your laundry softener; in most cases you can even eliminate the use of softener completely.