How to make your own Borax-free laundry soap

Guest post by Melissa
How to make your own Borax-free laundry soap
Laundry Soap Vinyl Label from

Without going through the rant about how a lot of commercial laundry soaps have really brutal chemicals, allergens, strong perfumes, and so on, they also are bad for the environment. There are lots of great eco-friendly soaps out there, but the best and cheapest soaps can be made at home from a handful of really simple ingredients.

This recipe is Borax free, Naptha free, perfume and dye free, and about as gentle as it gets. It’s great for babies, people with allergies or sensitive skin, and doesn’t leave residues.


  • 1 bar of soap (unscented, home made is best, but any natural soap is great)
  • 1½ cups baking soda
  • ½ cup citric acid
  • 3 tablespoons epsom salt

And that’s it!

bake the baking soda

Step 1: Bake the baking soda

“Wait, what?!” Yeah, I know… What you need to do is convert the baking soda to washing soda. You can buy washing soda, but it also typically has perfumes and dyes and such, and it’s super-easy to make it yourself.

For the science-inclined, baking soda = sodium bicarbonate, and washing soda = sodium carbonate. By heating it, carbon dioxide is released, and the extra carbon atom goes with it. SCIENCE!

So, take one cup of the baking soda, and spread it on a pan. Bake for 2 hours at 400°F, stirring halfway through. Let it cool. Keep the other 1/2 cup unbaked. Because this takes some time, and a lot of oven time, it’s a good idea to do this in bulk, and save the rest.

GIGANTIC WARNING: Once you’ve baked this into washing soda, it is a caustic cleaning agent and cannot be eaten. Don’t let its innocent, white, powdery appearance deceive you into thinking it belongs in cookies. It now has the same pH as ammonia so OMG DUN EAT!

Step 2: Grate the bar of soap

Take a very fine grater, and grate the bar down to nothing.

Bring in the super food processor if its clumpy

Step 3: Mix the ingredients together

Mix the cooled washing soda, soap, salt, remaining 1/2 cup of baking soda and citric acid together in a bowl. If you don’t let the soda cool completely, you will melt the soap, so don’t do what I usually do and just assume you can throw it in warm. You get a soupy mess. Just let it cool first.

Because the soap is soft, and citric acid is clumpy as fuck, if you don’t store it right. It’s a really good idea to run this whole thing through a food processor. I use this little Cuisinart food processor, because it’s wickedly powerful, and you don’t have to store this massive, insane appliance in your house. I use it all the time.

All declumped, and ready for storage
All declumped, and ready for storage

Step 4: Store it

Because this is a natural soap, it has a tendency to clump up. Store it in an airtight container, and add a pouch of dessicant to keep it dry. (Dessicants are the little silica gel packets you get in a lot of products. Just hang on to them, because they’re really useful.)

Natural laundry soap is great for hard and soft water towns, and won’t leave a residue on your clothes. It costs five times less than commercial detergents, and you can use less of it!

This post originally appeared on Urban Homesteader

Comments on How to make your own Borax-free laundry soap

  1. This looks so easy to do! Very cool. Definitely bookmarking to do sometime.

    I know there are lots of reasons you might want scent-free laundry soap, but for those of us who like a nicely scented load of laundry, can you add essential oil to this? Or would that somehow chemically ruin the soap. (Or maybe the scent wouldn’t linger anyway…) Input from those who use these sorts of recipes is appreciated!

  2. Thank you for this! I’ve been making my own laundry detergent for about a year (so much cheaper!), but I absolutely HATE the strong scent of the Fels-Naptha. I’ve tried it with Dr. Bronner’s, but I felt like it didn’t clean as well. Maybe this recipe will do the trick!

    • I made a batch that called for Fels-Naptha, but I used Ivory soap instead. An artist friend recommended cleaning your acrylic paint brushes with Ivory soap, so I had extra bars. Thank you for the warning about the smell of the Fels-Naptha!
      The only thing that that recipe doesn’t clean well is athletic quick-dry type clothing. It’s great for everything else, though.

  3. Hi there,
    I just wanted to leave a word of warning, not for those who already use this sucessfully, but for first-time users. While I have never tried this recipe (or any home-made detergents) I am a student of textile technology and know quite a bit about washing clothes:
    Firstly, please check the pH-value before you use this for wool (wool detergent has an acidic pH, because that’s least damaging to wool). I’m guessing this detergent is alkaline.
    Secondly, make sure you know how much it foams before leaving your machine unattended (I have no idea what washing machines you use, but there are some that move around a lot, those cannot handle too much foam and will eventually flood). If you have a newer model/front loader this is more of a danger. In Germany we have these models and all our detergents have formulas which include de-foaming agents.
    Thirdly, while there are ingredients in this recipe that are supposed to bind the limestone (? the Ca+ and Mg+ ions, they are bound by the baking soda) in your water, I am not sure how effective they will be. This also depends on the amount of those ions in YOUR water. Hard water can damage your machine in the long run (years!). On commercial detergent there are usually (at least in Germany, I don’t know about America) different amounts of detergent listed for different water hardnesses (and amounts of dirt). Check with your wate-supplier and make sure you use the right amount of detergent.
    I really love making my own stuff (especially soaps), so I totally get making my own detergent. Please don’t take this as criticism, just a bit of a safety-instruction.

    • I’ve used this recipe on regular and front load washers, and it doesn’t foam at all – if anything it foams less than any commercial detergent I’ve used.

      As far as pH, I haven’t tested it, but I suspect you’d be right in that it would be somewhat alkaline.

    • Nothing new to add here, I just wanted to thank you, sommerkind, for your interesting comment. Now I want to go read my detergent bottle to see what information it imparts, as I don’t think our US labels have nearly as much info as your German ones do… 🙂

      • I think it’s really interesting how they handle labelling in different countries. I’ve used Thai detergent this summer on holiday and it foamed like crazy, we had a bit of a mess afterwards 🙂 And I’ve heard that American detergents usually have a lot of Chlorine compuonds to kill more bacteria at lower temperatures.
        You see, I may be a little bit nerdy about my washing 🙂

  4. This sounds great, but do you know how well it works in hard water? I can’t use washing powder here as our water is as hard as it gets without having rocks in it! Have to use liquid detergent.

  5. This is cool! I’ve been interested in making my own laundry soap for some time, but don’t have access to borax (they don’t seem to sell it in my country). Just one thing I’d like to clarify- when you say natural soap, what ingredients are you screening for? SLS? Thank you!!

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