I recently made my own laundry soap. I've been cloth diapering for awhile and I do enough laundry that I thought it would be fun to try it. It turned out to be really easy and I love the finished product! I used peppermint soap so I think it actually makes laundry smell fresher and seem cleaner than using conventional laundry soap.
1/2 cup 20 Mule Team Borax
1/2 cup Arm and Hammer Super Washing Soda
1/2 bar Dr. Bronner's Pure Castile Peppermint Soap
4 quart pot
1/2 cup measuring cup
Grate 1/2 of the bar of Dr. Bronner's Pure Castile Peppermint Soap. Bring 4 cups of water to a boil and stir in the grated soap until dissolved. Add the 1/2 cup washing soap and 1/2 cup borax and stir until dissolved.
Fill a container with 1 1/2 gallons of water. Pour the soap mixture into the water and stir until combined. Set aside and allow to sit undisturbed for 24 hours.
The resulting mixture may be slightly globy, but after a stir it's ready for use! I use 1 cup of homemade detergent per load of laundry. It works perfectly! Edit 7/24/14: I switched to using 1/4 cup per load based on the comments below and that works just as well. I'm sure you could use even less but I like my clothes (and the cloth diapers) to come out extra clean!
I stored my homemade detergent in an old apple juice container and a smaller food storage box. If you double the recipe and store the detergent in a 5 gallon bucket, you'll make enough detergent to last for a few months.
I can still make alot more laundry detergent from my remaining ingredients. If you try this yourself, let me now how it goes for you. Happy laundering!