We were surprised to see how simple it is to make your own laundry detergent. No, you don't have to make your own, but hey- this is even a good recipe to keep on hand in case you run out of detergent and need to do your laundry in a hurry.
Here's Amanda Soule's recipe:
Homemade Laundry Powder
(Makes approximately 5 cups)
2 cups (finely) grated castile soap*
1 cup borax
1 cup baking soda
1 cup soda ash (washing soda)
Read her full post for the details on how she makes it here.