It only takes three ingredients: Borax, washing soda (NOT baking soda) and Fels Naptha laundry soap. I've heard of people using Ivory soap in their recipe, but I can't tell you how that works since I've never tried it. These three items took a bit of searching for me to find. My beloved Target only carried the Borax - say it isn't so, Target! But after searching a few grocery stores, I found one that carried all three.
You'll need to grate the bar of soap first. Everywhere I've seen this recipe online I've seen people hand-grating the soap. A little something I learned: Those people are crazy! Unless you're up for a strenuous arm workout, don't try it. This soap is really dense and doesn't grate easily! I took out my handy-dandy food processor* and grated it that way. Just cutting the soap into slices to put into the processor was arm workout enough, thankyouverymuch.
I then dumped the grated soap into a plastic tub (Why yes, that is a giant Red Vines tub I'm using. I'm not addicted to Red Vines. I can stop at any time. I just don't wanna.) and added 3 cups of washing soda and 3 cups of Borax. Mix well!
Find yourself a scoop you can use. Mine is an old coffee scoop that holds about a tablespoon. For a regular sized load of laundry, you'll only need to use 2 Tbsp. of soap. Yup! That's all you'll need! And since this soap won't get all foamy, it can be used in front loading washers, too. I've given some to both my mom and sister to use in their front-loaders and there hasn't been any problems.
This soap recipe will last you a good, long time, too. The ingredients cost much less than commercial detergents out there, and who doesn't love a bargain? I've been really happy with how well it cleans, too. The first thing I ever washed with it was my dog's very dirty bed cover. Ick. I was shocked to find it came out looking like new! If you have stained items you're going to be washing, you'll still want to pre-treat them like you normally would. This stuff is good, but it's not a miracle worker. I like it just as well as I did the Tide I used before, so that's saying something.
So, happy laundering! And remember, stay away from the grater. You'll be a happier person that way.
* If you have a light-duty food processor, you'll want to be careful if you try to grate the soap in it. Like I said, that soap is dense. You don't want to burn out your processor's motor!