KETCHUM - The "Trout Friendly Lawn" sign outside Bill and Jeanne Cassell's Ketchum home has spawned a host of questions.

"Where are the trout?" youngsters want to know.

The Cassells had to meet criteria to get the sign. They replaced some of their lawn with bark, reducing the amount of water they use. They water only between 10 p.m. and 6 a.m. - and only every other day.

They use native and drought-tolerant plants to reduce watering. They leave grass clippings on their lawn to fertilize the soil. And they've reduced their use of synthetic fertilizers and herbicides - all in an effort to protect the health of the Big Wood River and the fish within it.

These practices are growing - and not just to protect streams and fish. Increasingly, people are worrying about the effect of pesticides and herbicides on humans and pets.

"I have an infant, and pretty soon everything she picks up will go in her mouth. No way am I going to put herbicides on my lawn," visiting speaker Paul Tukey said.

Tukey has more reason than many to be wary of herbicides. He owned a million-dollar landscaping business in Maine when a doctor told him that 2, 4-D weed killer was causing his recurrent headaches, nosebleeds and blurred vision.

"He told me I had acute chemical sensitivity and that if I continued to use the chemicals I was going to wind up dead," Tukey said. As he researched the issue, Tukey began learning that 2, 4-D was also being linked to Parkinson's disease, prostate and other cancers, rashes, attention deficit disorder and immune suppression.

"It's very toxic to dogs," he said. "Dandelions or cancer: You decide."

Tukey began experimenting with organic lawn care, eventually taking over the care of the National Mall in Washington, D.C. And he wrote "The Organic Lawn Care Manual" and started a show by the same name on HGTV.

In October, the Sawtooth Botanical Garden brought Tukey to Ketchum where he screened the new film "A Chemical Reaction." The documentary tells how the Canadian town of Hudson, Ontario, banned pesticides in 1991 after a doctor began noticing a connection between her patients' health and the use of lawn chemicals. Today, the sale of pesticides is banned in Canada, Denmark and Norway, according to Tukey. And Connecticut has made it illegal to use weed killer in schoolyards.

But chemical companies got laws passed in most states, including Idaho, that make it impossible for local municipalities to ban pesticides across the board, as Hudson did.

America's obsession with treating lawns chemically began in 1967 when the Masters Golf Tournament was televised in color, Tukey said. Today, however, people are realizing that it's possible to have beautiful lawns using organic methods that their grandparents may have used.

One of the keys is to compost with decayed matter that used to be alive. The compost should have a sweet, earthy smell to it, he said. And you should rake a half-inch layer across your lawn so you don't suffocate the grass.

Vermicompost, or worm poop, is the greatest fertilizer you can use on your garden, he added.

"A lot of people think going organic means you will be overwhelmed by dandelions and insects. But weeds simply indicate that your soil is not healthy and needs nourishment. And insects appear as response to fast growth spurts caused by synthetic fertilizer," he said.

Organic lawns don't need to be mowed as often. And they need 70 percent less to water to stay green.

"Your goal is to water once a week, if that," Tukey said.

Some lawn companies, such as TruGreen in Twin Falls, offer customers a choice of organic products, as well as more conventional treatment. Company spokeswoman Amy Simpson said the company is also utilizing new technologies that allow landscapers to spot-treat weeds rather than blanket a lawn with chemicals.

"Absolutely, you can have a nice lawn without using chemicals," she said.

Bill Pereira, a third-generation farmer, said he started Big Chief Organics, a fertilizer business, after nearly 40 years of farming and landscape work in Hagerman.

"There's tons of information about the downside of synthetic fertilizers - cancer rates going through the roof, dogs getting sickened, the problems of nitrates ending up in our water," he said. "But, unfortunately, so many people are more interested in what's cheap and quick, rather than what's safe."

One customer that has pursued "safe" is the city of Hailey, which has been using Pereira's Big Chief Organics fertilizer on its parks for the past two years. The fertilizer is derived from such products as bird and bat guano and fish emulsions.

"I believe that certified organic fertilizers is the only way to go when it comes to taking care of your home turf, parks, school grounds, even alfalfa fields," Pereira said. "Not only is it safer for the children and dogs who run on the lawn, but it can be less expensive than many of the chemical lawn services. And it can reduce the amount of water your lawn requires, as well."

Karen Bossick may be reached at kbossick@cox-internet.com or 208-578-2111.