Jul 10, 2008
Water the Plants, Feed the Soil
My youngest assistant, seen here, hasn't quite got the concept down, but you can: the most efficient way to irrigate (especially in these hot dusty times) is to put just as much water as needed as close to the plant's root zone as possible. This is the principle behind drip irrigation, and it can work equally well with attentive hand watering (for which 4-year-olds are not known).
The other half of the equation is the nutrition your plants are getting. It's tempting to toss a handful of Osmocote or Miracle-Gro (did you know they're both made by the same company?) at the bases of your plants. But this only supports root development at the base, where the roots already are; it does nothing to encourage them to spread out into new ground, which in turn increases the plant's ability to take up water (especially in these hot dusty times).
A great way to enrich the soil on a broad scale is with consistent and generous applications of compost mulch; aim for 2-3" every 6 months. Added bonus: a healthy layer of mulch also helps prevent your precious water from evaporating, which keeps your efficient irrigation practices efficient.
(By the way, you'll notice the mulch is conspicuously lacking in my photo. Just do as I say, not as I do.)