Soap nuts grows on the Sapindus tree which plays an important role in the eco system. The trees grow without any pesticide and creates a fertile soil. You need to use 3-6 shells depending on the water condition, if it is soft or hard water in your area. The shells washes efficiently without any phosphates and chemicals and are gentle to your skin and to your laundry.
We bought our soap nuts at Budgens in Islington, London. £7.75 for 225 grams of soap nut shells and it will last for 55 washes and 108 washes if you make it into liquid detergent (instructions to make liquid detergent is written on the box).