The Last Irrigation

The only plant activities happening this time of year are food storage and some root growth. That means you can turn off your irrigation system and let your landscape go dormant.

The end of October is traditionally when we turn off the irrigation system and let plants naturally go dormant. Landscapes that are dominated by native plants and adapted non-native plants can go without supplemental water because it’s normal and natural for these plants to go dormant.  Even semi-evergreen and evergreen plants go into dormancy, albeit a little later in the fall than deciduous plants.

The median rainfall over the past 30 years for late fall and winter has been about 5 ½ inches. This is more than enough water for plants that have stopped all food production and reproduction. The only plant activities happening this time of year are food storage and some root growth.

So, is there a need to water weekly or even every other week in fall and winter? No way! Even in exceptionally dry winters, we may recommend a deep soaking every 45 days or so.

Why not try my holiday method? Pick three holidays – any three – from November to March (I like to use La Posada, MLK Day and St. Patrick’s Day). Use only those days to water your landscape. This also prevents you from having a high sewer bill for the following year since you are not using water during the Winter Averaging Period.

Rely on winter rainfall and add supplemental water only when absolutely necessary. Save water and money.

Picture of Mark Peterson
Mark Peterson
Mark A. Peterson was a conservation project coordinator for San Antonio Water System before retiring. With over 30 years of experience as an urban forester and arborist, Mark is probably the only person you know who actually prunes trees for fun. When not expounding on the benefits of trees and limited lawns, you're likely to find him hiking San Antonio's wilderness parks or expounding on the virtues of geography and history to his friends.
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