Landscaping Chemical Whets Curiosity : Drought: Vendors say adding polyacrylamide to a lawn keeps it lush and green with 60% less water. Critics are skeptical. The results are mixed.

True believers are calling it the wonder drug of landscaping.

All Southern California residents need to do, they say, is to add something called polyacrylamide to their yards to keep them lush and green for years while using up to 60% less water.

In an era of water rationing, the potential appeal is enormous. Even its proponents say it seems too good to be true.

But the critics who challenge its effectiveness are calling it a case of drought-induced merchandising.

Mostly confined in the past to behind-the-scenes uses, the water-absorbing chemical recently has become a hot topic. From Los Angeles County’s high desert to San Diego, vendors have persuaded many public agencies to try it.

The results have been decidedly mixed.

The Rose Bowl in Pasadena quietly used it two years ago and ended up with turf so wet it had to be removed. Caltrans says it has helped keep freeway trees alive but also caused some problems. But officials at UCLA say it has been a water-saver for their baseball and soccer fields.

In Beverly Hills, city officials said they have used the chemical to save water on flower beds in the median of Rodeo Drive and plan to add it at Will Rogers Park. But at Los Angeles International Airport, officials said one brand of the product hasn’t worked well, so they’re looking for another.

Los Angeles city parks officials are planning their first test at Serrania Park in Woodland Hills later this year. San Diego city parks officials also are about to begin a test at four parks. And Lancaster is considering requiring it for most new landscaping.

The next marketing target will be homeowners. In the past, there was no practical way to use the chemical on established lawns. It had to be tilled into the ground before planting. But new injection machines may breach that barrier.

“People are just going nutso over this little product, and rightly so, because it works,” said Mike McWilliams, owner of Sand Castle Hydroseeding in the Antelope Valley. After persuading city officials in Palmdale, he was paid to inject the chemical into areas of the city’s golf course.

But enthusiasm for polyacrylamide is hardly unanimous. Some turf experts say the injection machines can harm lawns by severing roots. Others say claims of water savings appear unproven and wildly exaggerated. And the cost can range from hundreds to thousands of dollars for a typical yard.

“My feeling is they’re not useful,” said Jim Downer, a state researcher based in Ventura who complained that too many articles on the substance have read like ads. “We can save water and do so much more with mundane conventional things. But people want miracles. That’s why they’re so popular.”

Whether polyacrylamide works or not, the small granules, which resemble rock salt, are intriguing to observe. Part of a broad group of chemicals called polymers, which they’re often called generically, they swell rapidly into marble-sized balls of a gel-like material by absorbing and holding water.

Mixed with soil before planting or injected several inches underground afterward, the granules can hold up to 400 times their weight in water for five to 10 years, vendors claim. They say water is saved because the granules release it to the roots but prevent it from evaporating or seeping below the root zone.

“I’ve never been involved in something that does so much good,” said Bob Burdick, a spokesman for San Diego-based Broadleaf Industries Inc., which sells a polyacrylamide product called Broadleaf P4.

Other polyacrylamide or similar polymer-based brands include Drought Busters, Agrosoke, Hydrosource, Water Crystals and Terra-Sorb, according to state records. Store prices run about $10 to $12 a pound. Suggested application rates range from five to 40 pounds per 1,000 square feet.

But critics claim polyacrylamide loses much or most of its water-holding capacity when exposed to California soils, some fertilizers, and salts and minerals commonly found in municipal water systems. And, they argue that product claims and water savings have not been independently verified.

Downer, a landscape specialist with the University of California cooperative extension, said a test he conducted on grass last year showed no benefit. And Richard Evans, a researcher at UC Davis, said his research with plants also showed no advantage.

While disputing the quality of the testing, C. Dean Piper, Broadleaf’s chief research official, said that minerals make the chemical less effective and that he wouldn’t use the current injecting machines on his lawn. But he insisted that the chemical works and says better machines are forthcoming.

Even proponents agree that the chemical is being hyped. And new sellers are popping up like weeds.

“There’s a lot of variation associated with how effective these materials can be. The environment you place them in has a lot to do with it,” said Steve Wong, an official with the state Department of Food and Agriculture. It has licensed about a dozen distributors for such products since 1988.

Apart from a few tests that have drawn mixed results, probably least known about polyacrylamide is how well it works when injected into existing lawns. Those who have used it are more optimistic about its effectiveness when applied before planting.

Drought Busters

The drought has spurred a growing campaign promoting the use of a chemical polymer called polyacrylamide that suppliers claim can reduce the need for watering of residential or other landscaping by up to 60%. But its merits is being debated, and some researchers say the claims are exaggerated and unproven.

SOWING POLYMERS The polymer starts out as small granules resembling rock salt. It can be tilled into the ground before planting or injected under existing landscape using new machines. Suppliers are pitching the product to homeowners as a way to maintain lush grass and shrubs in an era of water-use restrictions.

ABSORBENCY Once in the soil and watered, the chemical supposedly can absorb and retain several hundred times its weight in water, and turns into a gel that nurtures plant roots. Suppliers say one application of the chemical, mostly used by nurseries, can remain effective for years.

THE DEBATE Some researchers who have studied polyacrylamide contend that salts and minerals in water supplies and the soil can drastically reduce its effectiveness. They argue its use on lawns can be counterproductive. And it can cost the typical homeowner hundreds of dollars to apply.