I recently plumbed my washing machine to greywater feed 3 trees in front of my house, one of which is a fruit tree.
I bought "Honest" detergent, supposedly plant-based and "eco-friendly", but... who trusts advertising?
Any commentary on what even these "eco-friendly" detergents can do over time to the soil in the outlet area?
Are there better commerically-available detergents out there?
I am just "filtering" by having the outlet subterrainian in an upside down put in a trench that it mulched 6" deep and leading around each tree.
Some greywater-safe detergents have been talked about in this thread.
Soap Nuts by NaturOil come from trees that produce seeds with a lot of saponins. Basically, saponins give the nuts a sudsy quality along with the ability to inhibit the growth of other organisms. If you're up for it, I found a great powerpoint online about the chemistry behind saponins.
Here's a nice video from the Survival Training School of California on saponin producing plants:
The music in the background is rather melodramatic for my taste, but nonetheless it is a nice presentation.
Plants For a Future and Mother Earth News both list plants that you can grow to make your own soap or detergents.
I have no idea what any of the "eco-friendly" detergents would do to the soil. The cleanest detergents and soaps I know of are the ones nature has made: saponin-producing plants!
The MOST important thing is not what the products will do to your plants, but what they do to the soil. SALTS of any kind are BAD!.
"Greywater is a fantastic way to save water, however, the products that we use to clean ourselves and our household items can be detrimental to the soil and plants that are watered with it. To minimize future soil problems, one must be a bit discerning when choosing cleaning products. Many products like bleach or other chemicals can kill plants outright. Even if a product is labeled as “biodegradable,” “natural,” or “eco-friendly” , this does not mean that is good to use for watering your yard. Due to low rainfall and high evaporation rates in San Diego many ingredients that would be perfectly fine in wetter climates can build up in our soils and cause long term problems. To ensure healthy plants and soil, keep these three ingredients to a minimum:
Salt or Sodium anything (examples include sodium lauryl sulfate, sodium hydroxide)
Boron or borax
For a full list of ingredients to watch out for and to learn more about greywater friendly soaps and detergents check out this site."