How to Water The Garden

At this very moment, somewhere on our vast planet, it’s raining. But at the MOTHER EARTH NEWS EcoVillage garden, we’re in the middle of a typical summer dry spell . . . so I’ve been busy soaking the bases of our tomato plants with a watering wand.

Most of us — with the twist of a spigot — can turn a garden hose into an umbilical cord linking us to vast (yet not inexhaustible) underground rivers. And since many of us don’t need to worry about the availability of water, being blessed with adequate supplies, we can often afford, instead, to fret about when to water . . . how much moisture to put down . . . what implements and techniques are most appropriate to use . . . and how to conserve as much water as possible while still nurturing the crops.

These are the concerns we’ll address in this article. But first, let’s review some fundamentals about . . .

Soil and Water

Water provides more than just liquid to a plant; it’s also the medium that enables nutrients and minerals to enter the roots. (Roots don’t digest dirt — they’re not “woody earthworms” — but instead obtain their nutrients only in solution.) What’s more, through the process of photosynthesis, some of water’s hydrogen is split off to become a constituent of the carbohydrate compounds that make up most of the body tissue of growing plants.

Interestingly, water also enables plant roots to obtain nutrients that are beyond their physical reach. At varying depths below our feet lies the water table. Above that is soil containing minute, air-filled vestibules. When enough moisture surrounds each soil particle to create a continuous film from roots to water table, plants can, by capillary action, draw water and thus food from places far beneath their roots. (When this happens, the soil is said to have reached field capacity.)

If, on hot summer days, the crops use more water than is replaced, dry air spaces are created within the soil, and the bridge to the water table is broken. Conversely, if a real downpour hits and the air spaces become flooded to the point of excluding oxygen altogether, plants can literally drown — because roots must have air available, as well as water.