Science Project: DIY Liquid Laundry Detergent

Science project time! Looking at recipes and imagining the outcome is so much fun. Combine that with a simple science project that you can use to save money and you’ve got yourself a multi-tasker’s dream!

My family never used the powder detergent because it wasn’t as good (aka required a little more effort and care than liquid soaps not something a single mom of 3, and later a family of 7, would undertake!) So we used liquid and if Tide was too expensive, we’d grab Sun or some other good but cheaper brand.

I come from this same mindset, only I’ve tried Arm & Hammer and some other dirt cheap liquid detergents. They were terrible and not worth the sale price! I think I’ve only used powder detergent once but I didn’t like having to wait for the powder to dissolve in the water on top of waiting for the water line to be reached so I could put in the rest of my clothes. Liquid is just so much more convenience, even when you have to be mindful of getting the detergent on the fabric.

sarah vigue diy detergent organic homemade detergent recipe

For some reason, a lot of homemade recipes make big yields (10-12 gal.) The recipe below make just over 2 gal. so if you don’t need a vat of laundry detergent, try this recipe instead! Here are the ingredients for homemade laundry detergent that will work about at well as name brand detergent.


  • 1/4 bar (5.5 oz.) Fels Naptha soap (a stain remover)
  • 1/2 cup white or apple cider vinegar (optional)
  • 1/4 cup (4 T.) Arm & Hammer Washing Soda (not baking soda)
  • 2 slightly rounded T. Borax powder
  • 20 cups water (used in 2 sets)
  • 2 c water


Take the quartered bar of the Fels Naptha. Set aside the rest of the bar for future use. Dice or shred the 1/4 of the stain remover bar and put it in a large pot, containing the 2 cups of water, on medium heat. Continuously stir the mixture until the soap shreds are melted. Make sure to scrape the sides and the bottom of the pan to prevent burning. Add the Borax and the Washing Soda.

TIP: As the temperature rises, keep your face a slight distance away from the fumes. They smell good, but after a few minutes, your eyes start to feel sensitive so just give your project some space and be grateful that no onions are involved!

Next, stir in 10 cups of water. Turn off the heat then add the remaining 10 cups of water. Stir well, remove the spoon and cover the pot. Let it sit for around 8 hours or just set it aside overnight. [Avoid letting the detergent set for 10+ hours. The texture of the soap becomes too much of a solid and you will have jellyfish like pieces that will separate, even after breaking up the soap. If this happens, the soap will still work but you will have to shake the detergent container before dispensing the detergent.] The soap will congeal, so when you remove the lid, add the vinegar and stir the detergent again.

At this point, you can just divide the liquid detergent concentrate you made by using a funnel to pour the soap into two 1 gallon containers (I use two cleaned 1 gallon milk jugs.) To dilute the concentrate and make the liquid soap ready to use, fill the rest of the containers with water and shake/stir the mixture. Use the same measurements you would use with a store-bought, brand name liquid detergent; 1/4 cup to about 1/2 cup, depending on how soiled the clothes are.

Do you want to try this? What variations on this recipe would you use?

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