Ultimate Guide to Soap Nuts: directions, tips, and tricks for organic, zero waste laundry, bug repelling, and truly compostable cleaning

You’ve probably at least heard of soap nuts and are interested to try them but have questions about how to use them, what they’re good at (and not good at), and how truly sustainable they are. In this article, we’ll try to answer all these questions and more.

That’s me, next to a soapberry tree in the Hoomaluhia Botanical Garden (Kaneohe, HI)

Soap nuts are very well named–they’re soap-generating nuts that come from (not kidding) the soapberry tree (genus: Sapindus, and in latin, sapo is soap, so the family is aptly named). The tree lives in tropical regions, where, given good soil and climatic conditions, it can produce seeds (the soap nuts themselves) after about 8-10 years of growth.

The nuts contain saponins, a surfactant substance that, when combined with water, produces a dirt and bacteria fighting soap (and even suds!). It’s the fruit pulp that has been used by indigenous cultures for thousands of years to clean, so when you buy soap nuts, what you get is the fruit of the nut, dried, with the pit/nut removed. The soap produced by soap nuts is gentle (so it’s great for delicate fabrics) yet effective (I’ve been using them for about six months on workout clothes, gardening clothes, biking clothes…it gets out sweat, dirt, etc.).

Among the best benefits of soap nuts, they are free of any chemicals, toxins, fragrances, etc., which are common in store-bought laundry soap. They’re also hypoallergenic, low suds (which make them great for high efficiency washers), and have a very small carbon footprint, because they weigh so little that shipping is easy (especially when compared with liquid soaps, which are very heavy and therefore require a lot of fossil fuels to ship).

Tips for using soap nuts to do your laundry

The primary use of soap nuts so far is laundry. You can hand wash fine fabrics just by adding some soap nuts to a large basin or bowl, soaking them for a few minutes, and jostling the water to extract as much soap as you want. Soap nuts will not leave much of a scent at all…even though they’ll be run through the primary wash cycle AND the rinse cycle, there will be a very light clean and maybe a little apple-ish scent, but barely detectable. Just…clean.

You’ll want to use about 5 nuts in a load of laundry. You can reuse these up to 10 times! As long as the nuts get adequate water (so see below for not overfilling your laundry), they’ll get your stuff clean.

Using a washing machine, follow these tips:

Use a muslin bag – you can grind the soap nuts down and just use them as powder, but they won’t disappear, meaning that little grinds will be in your wastewater or on your clothes. Better to just get a reusable muslin bag and keep the nuts whole in it, then re-use again and again.
Use cold water – yes soap nuts work great in cold water, and there is literally no reason to use hot water except if there’s grease in your clothes, or you want a higher electric/gas bill. Up to you. Soap nuts will release more saponin / soap in warm and hot water, meaning you’ll also get less uses out of your nuts and spend more on them than you need to. But if your soap nuts are getting close to done, maybe pre-soak them in a cup of hot water to really extract the last of the soap, then throw that cup of water in the laundry before running a load.
Add extra nuts if you have hard water – you will know you have hard water if you have trouble in your shower keeping soap suds on your body. Hardness of water is basically a measure of how much soap the water can dissolve.
Be realistic – soap nuts are great…but they are a nut. If you expect the same level of stain-fighting as a harsh toxic bleaching chemical that was distilled from crude oil, well…your expectations might cause you to be unhappy with the results.
Don’t overfill – soap nuts need water circulation in order to agitate and generate soap
Pre-treat stains – soap nuts will not get out many stains (believe me, I tried with red wine on a white shirt…the soap nuts were unable to remove that). So pre-treat stains before loading your laundry.
Use nuts up to 10 times, but checking them after 5 uses and judge how much soap is left – you’ll know your soap nuts are done when they’re dried, cracked, lose their sheen, look greyish, crumbly, and get thin. So just open the muslin bag and give them an inspection before running loads after you’ve used them 5 or so times.

Other uses, tips and tricks for soap nuts to clean your house or for personal care

Soap nuts can be used for a lot of other things. You can boil them in some water and use the resulting concoction (after cooling) for carpet cleaning, an all purpose cleaner, glass cleaner, stainless steel, and even jewelry. Similarly, generate some suds and spray the mix onto plants to deter pests. You can wash your car with it. You can also make some personal care products from soap nuts. The mild detergent is great for a body wash alternative, and also works great for people with eczema or other skin conditions.

So how many nuts do you use in how much water to create soap nut cleansers? That depends on you and how strong you want the resulting soap product. For an all-purpose surface cleaner (one of the stronger desired soaps in the home), I boil 5 nuts in about 4 cups of water for about 2 minutes, then let it cool, and use it for a number of things. I then re-use those 5 nuts in my laundry 4-5 more times after. If you’re looking for a much more concentrated cleanser, boil 10 nuts in 6 cups of water for about 20 minutes. Those nuts will be done-zo, so just chuck ’em in the yard after this. But you’ll be left with about 4 cups of concentrated soap liquid.

I keep any resulting soapy liquid (after I’m done cleaning) in the fridge to extend its shelf life. Remember – be realistic…these are nuts, not petrochemicals that nature doesn’t know what to do with. So when you make a soapy broth, it will “go bad” at some point.

Check out other soap nuts recipes here

The best part about soap nuts?

Use them again and again, and when you’re done, throw them in your garden where they will become food for soil microbes and nutrients for plants.

Here, we tried to provide as many answers about soap nuts as possible! Let us know in the comments if you have others, and we can always update the post. If you’re just ready to get going, buy your soap nuts here, which includes a storage bag and a wash bag!

Soap nuts picture from Pixabay

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Tags: compostable, eczema, healthy, laundry, soap nuts, truly

About the Author

Scott Cooney Scott Cooney is a serial eco-entrepreneur including being the solo founder of Pono Home, HomeEfficiency.com, and CleanTechnica; author of two books; former sustainability consultant with clients including Johnson & Johnson, Eastman Chemical, Wal-Mart, and Duke Energy; former Adjunct teaching the first course in sustainable business in the MBA program at UH Manoa; lover of local, healthy food and especially vegan nachos. Find Scott on Twitter