L.A. at Home

Design, Architecture, Gardens,
Southern California Living

« Previous Post | L.A. at Home Home | Next Post »

Dry Gardening column debut


Lawn  

Each week, Home contributor Emily Green (author of the blog Chance of Rain) will write about low-water issues for The Times. In this week's column, she breaks down the meaning of evapotranspiration and how that informs the way we water our plants.

"Until new city drought restrictions began in Los Angeles on June 1, the Metropolitan Water District estimated that our garden hoses and sprinklers applied roughly 84 inches of water a year on our gardens. That's four times the rainfall rate for Honolulu," she writes.

Read the full column after the jump:

Most of us learn about evapotranspiration in school. Rain or snow falls. As it forms rivers or soaks into the earth, a certain amount of it evaporates into the atmosphere. That's the "evapo" part. Then the roots of plants also absorb water from the earth and feed it to their leaves. During photosynthesis it is released back into the atmosphere. That's the "transpiration" part.

How fast evapotranspiration occurs and how much water is involved depends on a place and its plants. Tropical flora, flushed with steady water, grows in a fast, lush and often continuous fashion. Landscape designers would say it has an high ET rate.

Plants in dry Mediterranean climates such as ours use water sparingly. Faced with bone dry summers, Mediterranean plants typically become dormant in late spring through fall to conserve water.

These plants have low ET rates.

But in Los Angeles, we tend to use plants with high ET rates in a region naturally suited to plants with low ones. Because the climate is simply too hot for most plants with high ET rates, we are forced to water them at many times over the already high rate they would naturally require.

Until new city drought restrictions began in Los Angeles on June 1, the Metropolitan Water District estimated that our garden hoses and sprinklers applied roughly 84 inches of water a year on our gardens. That's four times the rainfall rate for Honolulu.

Most of that went on lawn, which has such a high ET rate that it typically goes brown in summer even in cold and rainy England. Were we less lawn-proud and closer to the sources of our water supply in Southern California, we might have made more regionally appropriate landscaping choices. But the networks of aqueducts serving us travels hundreds of miles north and east. We're all but unaware that we've pumped three of our major water sources near the point of collapse. To make matters worse, many of our local stores offer mostly high-ET plants such as turf.

To deal with the gathering crisis, Los Angeles issued its ordinance limiting how often we may water our lawns starting June 1. We could, water managers estimate, save a quarter of our total water supply by merely upgrading and turning down our sprinklers.

How do the water wonks know this? The steady ribbon of overflowed sprinkler water running through our gutters all summer is a clue. Yet the calculation mainly derives from looking at the E -rates of turf grass, then looking at how much turf there is and how much water it actually needs.

Suffice it to say that your average L.A. lawn does not need four times the annual average rainfall of Hawaii to survive, even in hot, dry Southern California.

Rather than confuse us with water math, Los Angeles and its Department of Water and Power have decided that our lawns will do just fine being watered twice a week for 15 minutes at a time.

As the restrictions kick in, water companies are also offering incentives for us to upgrade old, wasteful irrigation systems. The L.A. Department of Water and Power has more information.

For other rebates, go to the Metropolitan Water District member agency page and follow the links to your supplier.

Photo credit: Spencer Weiner

 
Comments () | Archives (7)

The comments to this entry are closed.

A large portion of our water is consumed in gardens. Today when fresh water levels in Southern California have dropped alarmingly, it is very important to spread awareness on water wise gardening. For instance California friendly plants use lesser water as compared to foreign species. Using mulch saves soil moisture and reduces the need to water plants regularly. In fact BeWaterWise has designed a calculator to figure out how much water a garden would need every week. Check it out at http://www.bewaterwise.com/calculator.html

There are many beautiful plants that happily survive in Southern California without much, or any irrigation at all. The desert gardens of the Huntington Library are stunning, and some L.A. Homeowners have already switched to succulents, which make for a much more interesting and colorful display than grass. See http://www.plants.am/wiki/Xeriscape for more info/photos on low water gardening.

Surfrider Foundation has an excellent program on Ocean Friendly Gardens with which we encourage people to use plants appropriate for our region and to capture what rainfall we do get with their landscaping. For info check out http://www.surfrider.org/ofg.asp.

And for info on free monthly workshops on Ocean Friendly Gardens sponsored by the Malibu/West LA chater check out http://surfriderwlam.org/

Surfrider Foundation has an excellent program on Ocean Friendly Gardens with which we encourage people to use plants appropriate for our region and to capture what rainfall we do get with their landscaping. For info check out http://www.surfrider.org/ofg.asp.

And for info on free monthly workshops on Ocean Friendly Gardens sponsored by the Malibu/West LA chater check out http://surfriderwlam.org/

Surfrider Foundation has an excellent program on Ocean Friendly Gardens with which we encourage people to use plants appropriate for our region and to capture what rainfall we do get with their landscaping. For info check out http://www.surfrider.org/ofg.asp.

And for info on free monthly workshops on Ocean Friendly Gardens sponsored by the Malibu/West LA chapter check out http://surfriderwlam.org/.

Surfrider Foundation has an excellent program on Ocean Friendly Gardens with which we encourage people to use plants appropriate for our region and to capture what rainfall we do get with their landscaping. For info check out http://www.surfrider.org/ofg.asp.

And for info on free monthly workshops on Ocean Friendly Gardens sponsored by the Malibu/West LA chapter check out http://surfriderwlam.org/.

My wife and I are on a mission to show that drought tolerant must not mean only rocks, cacti and succulents by planting flowering trees, bushes, sages and groundcover, very colorful and lush. We use only 33% of the new water allotment and have eliminated the need for mowing grass. Highly recommend the Surfrider Course; should have taken it a year ago! Olof


Connect

Recommended on Facebook


Advertisement

L.A. at Home in Print

In Case You Missed It...

Hot Property

Video

Recent Posts
New home for L.A. at Home |  July 17, 2012, 3:45 pm »
The Scout: What's new on Pico Boulevard  |  July 13, 2012, 8:22 am »
Review: Insteon remote-control LED light bulb |  July 10, 2012, 8:28 am »

Categories


Archives