- Author: Dennis Pittenger
[From the August 2015 issue of the UC IPM Green Bulletin]
A. Landscape irrigation accounts for only about 9% of total statewide developed water use, but the percentage varies widely among communities. Water applied to landscapes is estimated to account for about 50% of residential water consumption statewide, but the amount varies from about 30% in some coastal communities to 60% or more in many inland suburban communities.
Q. Does a landscape have to be re-planted with specific drought resistant, native, or California- Friendly plants to save significant amounts of water?
A. No. Field research studies indicate that traditionally used landscape trees, shrubs, and groundcovers have considerable drought resistance and perform acceptably with about 40% to 60% of the water required to maintain the average lawn in good condition. This is comparable to the water required by so-called drought resistant, California Friendly, and native plants to perform acceptably in landscapes. The common perception is that plants traditionally grown in landscapes are not drought resistant, so they are usually over watered.
Q. How much water can be saved by removing a lawn?
A. Water savings depends on how effectively the lawn has been irrigated, the type of turfgrass removed, which plants and how many will replace it, and how effectively the water applied to new plants is managed. If a lawn is removed and plant material is changed but the irrigation system and water management practices are not improved, then little water savings will be realized. If the lawn has been over watered and irrigation was poorly managed, then maximum water savings are possible by removing the lawn. However, in such situations keeping the lawn and simply improving irrigation management and improving or replacing an inefficient irrigation system will also generate substantial water savings without the trouble, cost, and the loss of aesthetics and functions that occur when removing the lawn.
A. As with lawns, it depends on the amount of water currently being applied. Plantings that have been maintained with high soil moisture content can usually maintain acceptable performance with a 20-40% reduction in irrigation by extending the interval between thorough irrigations as described above. Additional 10- 20% irrigation reductions to theses plantings or to plantings that have already been irrigated below optimum will usually allow plants to remain functional, but they will grow less, possibly wilt and drop some leaves. It is important to gradually reduce water over a few to several week period by extending the interval between irrigations and applying enough water to wet most of the root system at each watering.
A few deep, root-zone wetting irrigations spaced 3 to 6 weeks apart from spring through fall can be enough to keep most trees and shrubs alive when water is in short supply. Many tree and shrub species will drop leaves, wilt, or suffer dieback of some branches under severe water shortage, but will survive.
Q. When should trees, shrubs, and other landscape plants be planted in a dry year or if drought is expected?
A. Hold off planting until fall or winter to take advantage of cool weather as well as fall and winter rains. The planting site may be prepared in spring or summer, however.
To access this article in it's entirety, see the August 2015 issue of UC IPM's Green Bulletin or visit the UC Center for Landscape and Urban Horticulture
- Dennis R. Pittenger, Area Environmental Horticulturist, UC Cooperative Extension Los Angeles County/UC Riverside, dennis.pittenger@ucr.edu
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- Author: Gerry L Hernandez
Make every Drop Count
- Mulch
- Repair leaks and broken sprinklers
- Reduce overspray areas
- Adjust the system frequently to the season
Benefit:
- Conserve water
- Save money
- Urban landscape water use can be reduced by 50%
- Author: Gerry L Hernandez
Irrigation System
- Use an automatic controller on your irrigation system
- Use drip for your flower beds
- Replace old sprinkler heads with high efficient ones. If your system is over 10 years old check out the new sprinkler heads at your local garden center
- Use multiple run times if you have a lot of run-off before the timer shuts off. For example; you should irrigate every other day for 20 minutes but after 15 minutes the water is running off the lawn. Instead run the system for 10 minutes, wait 1 hour and run for another 10 minutes. This works especially well on slopes.
Benefit:
- Limit evaporation and run-off
- Limit disease
- Limit weeds
Remember, Master Gardeners do not recommend specific stores or products. You can purchase supplies any where.
- Author: Jeannette E. Warnert
“Landscape irrigation represents well over half the water use in the average household,” Ingels said. “There are many proven ways to reduce high summer landscape water usage and these strategies will be especially critical this year due to the unprecedented drought in California.”
An expert in environmental horticulture, Ingels has maintained research and education programs for the University of California for 22 years on water conservation, deficit irrigation, sustainable landscaping and alternative turfgrass species. He also coordinates the UC Master Gardener program in Sacramento County.
In the spring, when the air temperature is in the 70s in much of California, lawns need about one-half to three-quarters of an inch of water per week, Ingels said. In the heat of the summer, water needs increase to about 1 inch to 1.5 inches per week. Knowing how much water to apply is half the battle. The other half is figuring out how much water is delivered by your irrigation system.
To calculate your home sprinklers' output, Ingels recommends conducting a catch can test. Place small cans with straight sides, like pet food or tuna cans, on the lawn in several places and run the sprinklers for 20 minutes. Use a ruler to measure the water in each can and determine the average. Multiply by three to get an hourly irrigation rate. Detailed information about various lawn species' water needs in different parts of California is outlined in the free UC Division of Agriculture and Natural Resources online publication Lawn Watering Guide for California. The document gives watering guidelines for warm season and cool season grass species growing in 10 climate regions in the state.
Loren Oki, UCCE specialist in the Department of Plant Sciences at UC Davis, a landscape horticulture expert, has conducted research on a wasteful but common residential lawn-watering problem in California: runoff.
“Much of the water that is applied to lawns runs directly into the gutters,” Oki said. “Not only is this wasted water, but we have found that the runoff carries pollutants – including pesticides and fertilizers – into the gutters and, eventually, into waterways. The problem is that typical sprinkler systems apply water faster than the soil can absorb it, which leads to runoff.”
To prevent runoff, use “cycle and soak,” a setting available on many irrigation controllers.
“This means the sprinklers come on for short periods with breaks in between to allow water to move into the soil,” Ingels said. “You'll still want to apply the full amount of water each of the days you're allowed to water, but you'll need a few hours between waterings to be sure it all soaks in.”
Sprinklers that spray a mist over lawns are another cause of water waste. Much of the water evaporates before it reaches the ground.
“You can save water by converting to rotary nozzles,” Ingels said. “The nozzles shoot out streams of water that provide very uniform watering. They have been shown to improve efficiency by 10 to 20 percent.”
In landscape borders, homeowners can save water by using a drip irrigation system. Drip irrigation will target water directly where the plants are growing, so no water is wasted wetting ground in areas where plant roots cannot reach. For optimal efficiency, the system must be carefully monitored throughout the growing season.
“Drip can be a great water saver, but it can also waste water if the system is poorly designed, if it's allowed to run too long, or if lines are accidentally cut with a shovel or other tool,” Ingels said.
Another water-saving strategy is preventing evaporation at the soil surface. Ingels suggests topping the soil with bark, wood chip, straw or other mulch.
“Bark and wood chips provide a long-lasting barrier to water evaporation from the soil,” he said. “Straw mulch works well in vegetable gardens. It saves water, keeps down weeds, and helps cool plant roots in the heat of the summer.”
Whatever irrigation system is used, Ingels said it is essential to check soil periodically throughout the year to determine how wet or dry it is and adjust the irrigation schedule as needed. The easiest way to check soil moisture, he said, is using a screwdriver.
“Just push a screwdriver down into the soil,” he said. “When the soil is moist, it will go all the way down. If the soil is moist only a few inches, the screwdriver will only go down that far.”
A more expensive soil sample tool, which pulls out a soil core, can be purchased at some nurseries and irrigation supply stores. Soil sampling provides more information about the soil, which is useful for making irrigation decisions.
UC Cooperative Extension and its Master Gardener program have abundant information on water conservation in the landscape:
- UC Guide to Healthy Lawns http://www.ipm.ucdavis.edu/TOOLS/TURF/
- Water use on Turfgrass and Landscape Plant Materials http://ucanr.edu/sites/UrbanHort/Water_Use_of_Turfgrass_and_Landscape_Plant_Materials/
- Drought: Gardening Tips http://cagardenweb.ucanr.edu/Drought_/Drought_Gardening_Tips_/
- Drought: Irrigation Tips http://cagardenweb.ucanr.edu/Drought_/Drought_Irrigation_Tips_/
- California Master Gardener programs (by county) http://camastergardeners.ucanr.edu/California_Counties_MG_Websites/
University of California Division of Agriculture and Natural Resources is celebrating 100 years of UC Cooperative Extension researchers and educators drawing on local expertise to conduct agricultural, environmental, economic, youth development and nutrition research that helps California thrive.
Media contacts:
- Chuck Ingels, UCCE advisor, Sacramento County, (916) 875-6527, cell (916) 835-7458, caingels@ucanr.edu
- Loren Oki, UCCE specialist, Department of Plant Sciences, UC Davis, (530) 754-4135, lroki@ucdavis.edu
- Author: Mary B. Gabbard
This past Saturday with the temperature hovering near 95 degrees, I was able to complete all my errands without breaking a sweat, thanks to a very effective air conditioner in my Honda CRV. Pulling into my my driveway, I was reminded by my wilting garden, that a Honda air conditioner can only do so much. A quick check of my sprinklers revealed they weren’t working, and hadn’t been on all week. (So much for the 16 year old son as the gardener,... what do they say? “You get what you pay for...”) Anyways, what does this mean to a gardener, well, a full day of hand watering. I actually don’t mind this because it gives me a chance to see what’s going on in my garden, as well as providing some much needed “me” time. Today, as I sprayed my Hummingbird Sage (Salvia spathacea), up popped a Praying Mantis! These are my favorite insects! They have triangular-shaped heads with a compound eye on each side.
The Praying Mantis is the only insect that can turn their head a full 180 degrees. They are named for their front legs, which are bent and held together as if they are praying.
The one I saw today, was brown, although on other watering-days, (my sprinklers break a lot), I have seen beautiful green mantis. A mantis is considered a predator that will eat all kinds of insects, good and bad. Most unfortunate recipients of unwanted mantis attention are moths, crickets, grasshoppers and flies. I also search for the egg case of the Praying Mantis when I water. Females regularly lay hundreds of eggs in a small case that is typically attached to woody stems, tree branches, or as in my yard, under the eaves.
Very cool!