DRY Laundry Soap:
This is by far the least amount of ingredients when it comes to homemade laundry detergent. Three key ingredients that you can get from Amazon, Wal-Mart, or Smart & Final definitely year round: Zote Soap Bar / Washing Soda / Borax. Yes, I know the history of Borax and that is why I end up adding more washing soda than borax in the end. In reality it is a 1:1 conversion; one cup of borax and one cup of washing soda.
Step 1: Grate your soap; I have a separate grater solely for this. Cleaning it after is a pain so, I just let it soak in hot water for a while before I wipe it clean.
Step 2: Add the washing soda and borax cup by cup mixing with a metal spoon as you go to break up the lumps and coat the soap pieces to ensure they do not stick together. Keep adding and mixing until you have the amount of soap you want. I make around 5 lbs worth at one go and it lasts me months.
Use 2 tablespoons per regular wash or 3 tablespoons per heavy or full load. I add it when the water is starting then I grab the first piece of dirty laundry and swish it around to mix it all up. I have never had any issues with this blend clumping and it is safe for both lights and darks; no color fading issues either.