Rhubarb roots, as reproduced in Root Demystified. One square equals one foot.

This is a new vocabulary word for me:

You’ve heard of grey water and black water–but what is green water?

Well, if you’re a sailor, it’s a term for the water swamping the deck during a storm. That’s not what I’m talking about here. Amongst sailors of the soil (i.e. gardeners), green water is the water supply held around the roots of the plants. Water from rain or irrigation which does not run off the surface of the soil, nor run down through the soil to ground water, but which stays with the plant for its use.

Green water is a plant’s envelope of life. It’s also a space of water storage which we don’t often consider. We’ll invest in a rain barrel, but we will forget the massive storage tank which nature has placed under our feet.

If we have healthy soil in our yards, our plants have a baseline supply of water. It’s held in the space between the soil particles and in the bodies of the microscopic creatures which live in healthy soil. How much water? I don’t know, but the real answer is, enough. Plants acclimated to your local climate (natives or similar), living in spongy, healthy soil don’t need supplemental irrigation. Not even in the summer. (Drip line doesn’t occur spontaneously in the wild, after all.) Conversely, in times of heavy rainfall, healthy, spongy soils also resist flooding, swamping and rotting.

By focusing on healthy soils, and allowing rain water to percolate into the soil, we empower the plants to take care of themselves. That’s better for them, and less work for us!

It’s easy to have healthy soils and deep green water reservoirs. We just have to take some commonsense steps to allow life to develop in the soil:

• We stop adding fertilizers to our yards, even organic ones. They actually collapse the soil structure and make the plants into fertilizer junkies. Mulch, compost and worm castings are all a yard needs.
• We design our yards so they capture and hold rain water rather than ejecting it straight to the street.
• We leave the leaves. We keep our clippings and fallen leaves on our land, and let them return to the soil. Mulch is is vital to living soil, while bare soil is dead soil.
• We make our yards lush. Soil life occurs around the root zones of plants, so more plants means better soil.
• We plant trees, which the founder of TreePeople, Andy Lipkis, calls “living cisterns.”