Last May I worked with an educational group called Grey Water Guerrillas to run a workshop at our home to teach people how to design and install a simple grey water irrigation system.
The system uses our laundry grey water to irrigate two areas of the front landscape using 1" supply lines and half inch barbed outlets, all available from DripWorks USA. Each outlet has a small adjuster valve and the water is distributed over a mulch basin. The mulch basin is between 6 to 10 inches deep and the diameter varies according to the space available and plant size. The mulch filters the grey water and allows the soil microbes to work on the water and purify it. The mulch we used was just plain old wood chip. Nothing fancy - the cheapest and easiest to get hold of at the time.
The biggest change we faced was choosing the right laundry detergent. The first thing is to switch to liquid over powders as powders often contain sodium based bulking agents. Secondly, read the labels and avoid products that contain sodium, chlorine and boron.
Sodium is a salt that changes the pH balance and structure of soil, and since our soil is already quite alkaline, we do need to keep it to a minimum. Best not to try growing those finiky acid loving plants in our grey water irrigated area - azaleas and gardenias.
Chlorine is used in laundry detergent as a bleach, and it should really be avoided anyway since it is harmful to the environment. Hydrogen peroxide is a slightly safer alternative.
Boron is considered a plant micro nutrient, required in only very, very small amounts. Most soils provide adequate amounts of this chemical. Concentrations only slightly higher than those considered beneficial can cause severe injury or death to plants.
The recommended detergents include the following:
Dirty Dozen' include things like antibacterials, coal tar, and DEA which can affect hormones and cell functioning and development.
When we were looking for these grey water safe products we found we had to visit a number of stores before we found the right ones. To save you the trouble, I put together this store with Amazon where you can have the products shipped directly to your door.
For further reading, check out these great web sites:
- Brad Lancaster's wonderful Rain Water Harvesting site is an inspiration for those of us wishing to use less water in our landscapes
- Art Ludwig is a pioneer in the field of grey water, and his site is a wonderful resource
- The Campaign for Safer Cosmetics is has an eye opening set of articles about what ingredients are in our personal care products.
Diane E Downey is the owner of The Yard Fairy Inc, a North San Diego County based award winning landscape design and installation company creating low water, low maintenance landscapes that are as functional as they are pleasing to the eye. To arrange your consultation with The Yard Fairy, please call 760-814-1266 or email info at yardfairy.com today.