It's October - just in time to gather what you need to make your own FREE laundry detergent!
If you stroll the neighborhood, you're bound to run in to a tree that looks like this:
You might see spike-covered balls dangling from the tree or on the ground below. Inside these pods are a seed - the Horse Chestnut or Buckeyes as we call them in the US. (Conkers if you're in the UK). The Horse Chestnut is not an edible seed, but it contains compounds called saponins that can be used for washing things! As the seeds ripen, the spiky shell usually pops off, leaving the smooth brown seeds on the ground.
Saponins are named for their ability to form a soap-like foam when mixed with water. These compounds consist of a hydrophilic (water-attracting) and hydrophobic (water-repelling) part, which gives them detergent-like properties. In addition to horse chestnut, saponins are also found in yucca root, soapwort root, and soapnuts. Saponins act as natural surfactants. This means they reduce the surface tension between water and oils or dirt, helping to emulsify and remove grime. When mixed with water, they create a lather or foam, acting as a natural soap or detergent.
Horse chestnut trees are native to Eurasia, but many have been planted all over North America. Keep your eyes out for the distinctive leaves. They're often planted in parks and neighborhoods. If you notice a neighbor with a horse chestnut tree, offer to clean their yard for free - in return you get a bunch of saponin-rich seeds!
To Make the Liquid:
The general ratio for making horse chestnut laundry liquid is 1 part horse chestnuts to 2-3 parts water by volume. That ends up being about 5-6 horse chestnuts (1 cup when chopped) to 2-3 cups water.