Location: northern Arizona, USA, 6,000 feet elev, zone 5b
posted 2 years ago
Does anyone have any actual experience with throwing dishwashing water on yard/garden/compost pile? We live in a somewhat arid climate (northeastern Arizona, 6000 feet) and would like to conserve water wherever possible. I did some research on using dishwashing soap such as Dawn and it seems that in this type of dilution it shouldn't be a problem for the plants but I'm concerned about the effect on the soil life.
Ana Edey of the Solviva books designed and used a toilet system, also used the same system for the kitchen water of a big restaurant, where the black water went through a compost worm bin. She intentionally used all kinds of commercial cleaning products to see if they would harm the worms, and she has been using it for 20 years and says nothing has harmed the worms yet.
Personally in my greywater system I try to avoid too much sodium and table salt, but I use moderate amounts of soap and dish detergent and the soil microbes and plants don't seem to mind. We've had our bathing black water go to willow trees for almost 20 years and the trees love it, though there are no earthworms in the area anyway so I can't speak to that. That's the washing waste water from 50 - 100 teenagers who use god-know-what-all kinds of "products" on their hair, skin, etc.
Works at a residential alternative high school in the Himalayas SECMOL.org . "Back home" is Cape Cod, E Coast USA.