- Author: Jeannette Warnert
Facing costly water bills and stringent municipal water limits, some Fresno County residents and businesses are opting to replace their lawns with synthetic grass. However, research by UC Cooperative Extension environmental horticulture advisor Janet Hartin has found that fake lawns have significant drawbacks.
To begin with, synthetic lawns are superheating what are already urban heat islands like those found in Fresno County. In the City of Fresno, for example, the average summer temperature is 4° F higher than in rural areas due to the urban heat island effect. (CalEPA)
Hartin conducted her research in Palm Springs and Redlands. While average summer temps are 5 to 10 degrees higher in Palm Springs than in Fresno, temperatures in Redlands are very similar. Hartin measured the surface temperatures of synthetic lawns, black mulch, asphalt and plants between 3 and 3:30 p.m. on several dates between May and August for the last three years.
“The surface temperature of asphalt, synthetic lawns and black mulch were more than 65° hotter than plants in Palm Springs and 60° higher in Redlands,” Hartin said. “The highest temperature I recorded was 173 on synthetic turf in Palm Springs. Black asphalt adjacent to the synthetic turf got as hot as 170°.”
The surfaces of plants she measured for comparison – groundcovers, vegetables and turfgrass lawns – hovered around 90° to 95° in Redlands and 95° to 100° in the desert.
“Plants are so much cooler because of their transpiration, the process in which the plant releases water vapor back into the atmosphere, cooling plants and their surroundings. Non-living surfaces don't transpire, so they will never be as cool as a living surface,” she said.
The surfaces of concrete and light-colored mulches were warmer than living green areas, but not nearly as hot as surfaces of darker-colored materials.
More and more, sports fields are being converted to synthetic turf because of its durability and lower water and maintenance needs. However, the hotter surface when the weather is warm, and rigid base compared to the sponge-like quality of natural turf, has led to an increase in injuries, Hartin said.
“Managers of schoolgrounds, parks, playgrounds and sports fields in inland and desert communities should choose living grass over synthetic materials,” Hartin said. “Because of California water woes, the days of wall-to-wall grass in front and back yards should be behind us, but we don't want to get totally away from grass. Other alternatives to consider are drought-resistant groundcovers.”
Another concern is disposing of the fake grass when it is removed. According to the synthetic grass industry, the product is expected to last for 20 years. (Synthetic Turf Council) After that, it is difficult to recycle, so typically ends up in landfills.
Grass, on the other hand, is easy to recycle. Throughout California, mowed grass clippings – along with other green waste like leaves, prunings and leftover food - are being picked up separately from garbage and composted. The grass clippings play a key role in the quality of the compost produced by municipal recycling programs.
“Compost is best created when ‘browns,' like fallen leaves, are combined with ‘greens,” like fresh grass clippings, in a 50/50 ratio. After adding moisture and regular turning, the product is ideal for nurturing soil,” Hartin said. “Or, the clippings can be used as a mulch on the surface of soil to reduce weeds, conserve water and keep plant roots cool. You can't do that with fake grass.”
Grow plants instead
Hartin believes the best surfaces in front and back yards are living plants. Green living surfaces not only cool the environment, they provide habitat for pollinators and food for birds. Earth worms and healthy microbes break down organic matter under turf and groundcovers, which improves soil quality. Climate-appropriate plants also help reduce stormwater runoff and reduce soil erosion.
"The cooling and ecosystem benefits of growing plants outweigh their water and maintenance requirements," she said. “What we plant today is going to benefit the community for decades to come."
Read more:
In the valley, 'heat islands' of asphalt and fake lawn reach 170 degrees. What you can do, Janet Hartin, The Desert Sun
Once hailed as a drought fix, California moves to restrict synthetic turf over health concerns, CalMatters
Synthetic sports fields and the heat island effect, Sonia Myrick, National Recreation and Park Association Magazine
- Author: Saoimanu Sope
Earlier this year, officials in Southern California declared a water shortage emergency resulting in restrictions such as limiting outdoor water use to one day of the week. While mandatory restrictions vary across the region, Amir Haghverdi, UC Cooperative Extension specialist and associate professor of agricultural and urban water management at UC Riverside, is using research to pinpoint irrigation strategies that will help communities reduce their demand for water and increase supply.
Haghverdi and his team are responding to a hotter and drier California by working to identify changes that can make a substantial difference in water savings.
While behavioral changes such as preventing leaks and turning the faucet off while brushing teeth can help, Haghverdi's research focuses on methodical changes like stressing green spaces, planting drought-tolerant plant species, using non-traditional water sources, and investing in technology to better control water use.
Testing a lawn's limits
For six years, Haghverdi and his team have performed stress tests on turfgrass to identify the lowest percent of evapotranspiration rate (ETo) that it can withstand and still survive. To do this, Haghverdi's team applies different percentages of ETo, obtained from weather stations, and monitors the performance of each landscape species over time.
While both cool-season and warm-season species can be stressed and still maintain their aesthetic value for a few weeks to several months, Haghverdi's results showed that warm-season turfgrass species require less water and can withstand water stress better.
The actual duration that people can apply less water depends on the type of turfgrass, the weather conditions and the stress level. For example, results showed that hybrid bermudagrass (a warm-season turfgrass) during summer in inland Southern California could keep its aesthetic value above the minimum threshold for 30 to 50 days, depending on the weather conditions, with irrigation application as low as 40% ETo.
In contrast, tall fescue, a cool-season turfgrass, even with 20% more water, showed signs of stress after only a few weeks and could not maintain its minimum acceptable quality.
Plant drought-tolerant species
Haghverdi's work demonstrates that when water conservation is the goal, alternative groundcover species are clearly superior to all turfgrass species and cultivars that they have tested so far. In fact, his team has identified drought-tolerant species that can maintain their aesthetic values with a third to a quarter less water than cool-season turfgrass (as low as 20% ETo) and can even withstand no-irrigation periods.
Furthermore, extensive field trials showed that new plant species from different regions could be as resilient as native species in withstanding drought and heat stress while maintaining their aesthetic beauty and cool canopy. Occasionally, they have outperformed native species, underscoring the advantages of drought- and heat-tolerant species that are non-native.
Based on Haghverdi's preliminary results for minimum irrigation requirement in inland Southern California, creeping Australian saltbush, a non-native species originally from Australia, and coyote bush, native to California, were top performers. Considering cooling benefits, drought tolerance and sensitivity to over-irrigation, creeping Australian saltbush performed the best.
Counties are already using recycled water
Although he recommends renewing your landscape with drought-tolerant or low-water use greenery and identifying how long your green spaces can live without water, Haghverdi acknowledges that, while contradictory, the cooling benefits of landscape irrigation are essential in Southern California.
“This is one of the tradeoffs of water conservation,” said Haghverdi. “If the only goal is to conserve water, maybe people will conclude that we don't have enough water to irrigate landscape.”
Water conservation efforts could influence counties to stop or reduce landscape irrigation. The consequences, however, would result in hotter environments due to the heat island effect. The loss of landscapes means that the sun's energy will be absorbed into the ground, instead of prompting transpiration in plants, which helps keep environments cool.
Thus, stressing green spaces and investing in drought-tolerant plant species help reduce the demand for water, but increasing water supply is just as vital. Haghverdi urges Southern California counties to prioritize a supplemental water supply such as recycled water – an approach already implemented in Ventura, Orange and San Diego counties.
The Metropolitan Water District of Southern California's Pure Water Southern California Program, formerly known as the Regional Recycled Water Program, aims to do just that. In partnership with the Los Angeles County Sanitation Districts, the program will further purify wastewater to produce a sustainable source of high-quality water for the region.
According to the program's website, this would “produce up to 150 million gallons of water daily when completed and provide purified water for up to 15 million people, making it one of the largest water reuse programs in the world.”
Smart controllers save time, money and water
Making the best use of the water you already have relies on efficiency. Sprinklers that are poorly placed, for example, are not as effective as they could be.
“What I see often while walking my dog in the neighborhood is that there's a lot of runoff, bad irrigation and bad timing like when it's windy,” Haghverdi observed. “People usually set their irrigation timer and then forget it, but they don't adjust it based on the season or weather parameters. That's not going to help us conserve water, a precious resource, in California.”
Thankfully, Haghverdi and his team have done extensive research on smart irrigation controllers, which, simply put, are irrigation timers with a sensor built in. Generally, there are two types of smart irrigation controllers: weather- and soil-based controllers.
Weather-based controllers use evapotranspiration data to automatically adjust their watering schedule according to local weather conditions. Soil-based controllers measure moisture at the root zone and start irrigating whenever the reading falls below a programmed threshold.
Smart controllers that have flowmeters can detect leaks and be activated automatically, whereas rain sensors can stop irrigation during rainfall. Although both additions are ideal for large irrigation landscapes such as parks and publicly maintained green spaces, rain sensors are easy to install and effective for residential areas too.
When asked about cost being a hindrance, Haghverdi responded, “Not a lot of people know that there are grants for smart controllers – some that will pay either all or a majority of the cost.”
To check if grants are available in your area, interested individuals are encouraged to contact their local water provider.
“We need to move towards autonomous and smart irrigation [strategies], and water management in urban areas. That's the future. If we can build autonomous cars, why can't we build smart water management systems that apply the right amount of water to each plant species, can detect leaks and prevent water waste?” said Haghverdi.
To learn more about or stay updated on Haghverdi's research, visit www.ucrwater.com.
- Posted by: Lauren Fordyce
Knowing what weedy grass you have in your lawn or landscape is very important in being able to properly control it. Dallisgrass is a common perennial weed that is easily identified and grows in uneven clumps in lawns and turf. This growth pattern creates a tripping hazard as well as a poor playing surface for parks, front lawns, and athletic fields. Clumps must be dug out to prevent its growth. Solarization with clear plastic can help control dallisgrass.
For more details about the biology of dallisgrass, management methods, and extensive information about herbicides, see the newly updated Pest Notes: Dallisgrass, authored by UC Cooperative Extension emeritus advisors Michelle LeStrange and John A. Roncoroni.
For information on other weeds, see the UC IPM web page on weed resources and weed identification tools at http://ipm.ucanr.edu/PMG/menu.weeds.html.
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- Author: Pamela Kan-Rice
Nearly 170 turfgrass professionals, academics and scientists met at the Turfgrass & Landscape Research Field Day at the UC Riverside Agricultural Operations Research Station to learn about the latest research on turfgrass on Sept. 15.
Topics included drought management, drought-tolerant species and cultivars, weed control, salinity management, reclaimed water use and more.
New drought-tolerant cultivars that better retain green color during winter – UCR 17-8 and UCR TP6-3 – developed by UC Riverside's Turfgrass Breeding team were featured. Fifteen exhibitors showcased their services from irrigation supplies to fertilizer to seeds.
“This grass we're about to release — they meet the state's water requirements,” Jim Baird, UC Cooperative Extension turfgrass specialist, told the Los Angeles Times, which referred to Baird as “the state's Mark Twain of turf. Our LeBron of lawns. The Ira Glass … of grass.”
The new cultivars use about half as much water as most Southern California lawns and are soft to touch.
Participants visited bermudagrass demonstration plots and discussed them with the researchers.
“There are 24 bermudagrass hybrids developed by our breeding team and six commercially available cultivars as checks – ‘Bandera', ‘Bullseye', ‘Celebration', ‘Midiron', ‘Santa Ana' and ‘Tifway II',” said Marta Pudzianowska, UC Riverside postdoc researcher.
The Turfgrass & Landscape Research Field Day is held every year in September. More information about the 2023 event is online at https://ucanr.edu/sites/turfgrassfieldday.
- Author: Jeannette E. Warnert
The safety of the weed killer glyphosate, the active ingredient in some well-known Roundup products, has been the subject of attention recently because of lawsuits that connected the chemical to cancer in humans.
Based on extensive scientific research, U.S. regulatory agencies have not banned glyphosate, but the publicity has increased interest in alternatives to the herbicide, which is the most widely used pesticide in the world.
“Everybody is really clamoring for information,” said area integrated pest management advisor Karey Windbiel-Rojas. “Efficacy of organic herbicides is one of the most popular talks I am giving at the moment.”
Windbiel-Rojas and former UC Cooperative Extension environmental horticulture advisor Maggie Reiter launched research projects in 2019 to help fill knowledge gaps on the effectiveness of organic herbicides in urban landscapes – such as lawns, golf courses, parks, cemeteries and school grounds. (Reiter has since taken an extension educator position at the University of Minnesota.)
Organic herbicides are pesticides made of compounds that occur in nature; and synthetic herbicides are compounds developed in laboratories. While both can be more toxic or less toxic to people and the environment, some people prefer using organic methods or chemicals.
On a small scale, a variety of organic solutions to weeds are readily available – such as hand pulling, hoeing and mulching. For larger jobs, professional landscape managers prefer applying an herbicide and look to UC Cooperative Extension scientists to know how well different options will work.
Reiter set up a study on at Ridge Creek Golf Course in Dinuba, and Windbiel-Rojas set up a study on a landscaped area with a mix of grasses and weeds in a parking lot at Sacramento State University.
In the Dinuba experiment, Reiter applied organic herbicides on 25-square-foot plots in four replications. The active ingredients of the organic herbicides included such naturally occurring chemicals as citric acid, clove oil, orange oil, acetic acid (vinegar four times stronger than that found in most home pantries), soaps, and caprylic acid, which comes from coconut and palm kernel oils.
The plots treated with citric acid and clove oil remained as green and lush as the grass in the control areas, which hadn't been treated at all. The areas sprayed with the other organic herbicides showed significant injury two days after treatment. However, 19 days post-treatment the plots treated with caprylic acid and herbicide soaps had completely recovered. The plots treated with orange oil and acetic acid recovered after 28 days.
In the Sacramento State trial, Windbiel-Rojas used some of the same organic compounds, plus others with different natural ingredients, such cinnamon oil, pelargonic acid and ammonium nonanoate, which are drawn from fruit, vegetables and other plant sources.
Many products burned down both grasses and broad-leaf weeds after a few days, however, a couple weeks later, the weeds began to regrow or recover. In addition, some of the organic treatments are more acutely toxic to people than glyphosate.
“While organic, 20% acetic acid is very toxic to the person applying the herbicide,” Windbiel-Rojas said. “It will burn one's skin, hair and eyes so the applicator must wear more personal protective equipment than with some other herbicides. This material is also problematic to use in a public space because any bystanders could be exposed to drift during application.”
The research was published in the February 2020 issue of CAPCA Adviser Magazine. The findings of the research on organic herbicides for turfgrass are preliminary and UC IPM researchers will continue to investigate options.
Windbiel-Rojas will present “Glyphosate Alternatives and Organic Herbicides in Landscapes: Efficacy and Tradeoffs” at the Pesticide Applicators Professional Association Zoom webinar Dec. 2. View the agenda here: https://www.papaseminars.com/uploads/Seminars/11643.pdf. For more information and the registration link, visit https://www.papaseminars.com/seminars.