Walking into the small Florida City warehouse, Blair Blacker pauses to survey the towering pyramid of canvas bundles, each about the size of a punching bag, that contain the stock-in-trade of his business: human hair.

About 15 tons of it on a recent day, imported from China, neatly pressed into mats and ready to ship to farmers and nursery growers who swear by the horticultural benefits of Blacker's hairy wares.

"If you had told me when I was flying combat helicopters in Vietnam that one day I'd be sitting on 30,000 pounds of human hair," said Blacker, a retired Army colonel-turned-entrepreneur, "I'd have said you were crazy."

The mats stored in southern Miami-Dade County are part of a world marketplace for human hair. Uses range from the obvious, such as false eyelashes and wigs, to the more obscure: it's a common raw-material source for l-cysteine, an amino acid frequently used in baked goods such as pizza dough and bagels.

China and India exported more than $154 million worth of human hair last year, according to United Nations trade statistics. They are Blacker's main suppliers.

"It's not processed or dyed like a lot of hair we have here," said Blacker, whose own hair is silvery and neatly cropped.

The product, marketed as SmartGrow, is effective in keeping out weeds, and has even shown signs of increasing yield in crops like tomatoes, according to University of Florida scientists.

"It's really exciting. The first trial was just outstanding," said Aaron Palmateer, an associate professor of plant pathology who has conducted tests on the SmartGrow product at UF's Tropical Research and Education Center in Homestead.

There is an admitted yuck factor to using hair in lieu of herbicide, but Palmateer points out that common agricultural methods can be similarly unappetizing.

"For people who say, 'Oh my God, this is hair' and think it's disgusting, they should know these farmers put manure on tomatoes like its going out of style," said Palmateer.

Luis Naranjo, owner of one of the largest wholesale nursery operations in South Miami-Dade, swears by the hirsute stuff.

"In the beginning, we were saying, 'Human hair? What is this?"' said Naranjo. He now expects 80 percent of his nearly 1 million plants, like ground orchids, at Octavio Taylor Nurseries will be cozily blanketed with the mats by this spring.

The hair mats saved him $45,000 in pesticides last year, and $200,000 in labor. "We can't raise our prices the way the market is today, so we need to keep expenses down," said Naranjo, who has been a grower for two decades.

The mats range in size from 25-foot sheets that can be custom-cut for row crops like tomatoes to golfball-sized cubes to tuck around the roots of potted ficus trees.

Wal-Mart began selling the mats for home gardeners last spring in about 60 stores in central Florida. Dollar General just signed on to sell the smaller-size sheets at 1,000 of its stores.

SmartGrow relies on two hair brokers — in China and India — to procure the hair, which is boiled in 120-degree water, dried, loaded onto 40-foot boats and shipped via waterway to a port city in China. Then it is transported to the small town of Zhaoyuan, home of the SmartGrow factory.

The mass of strands is loaded onto an old-style needle-punch machine, formerly used to make carpets.

A hopper blows air through the hair to loosen it, and the strands are then woven into a loose felt-like mat of mostly dark and shiny follicles, with the occasional gray strand peeping through.

SmartGrow began as the brainstorm of Phil McCrory, an Alabama hairstylist, nearly 20 years ago. McCrory was watching television coverage of the massive oil spill in Alaska caused by the Exxon Valdez in 1989, when he noticed oil-covered otters swimming to shore.

"I noticed how their fur soaked up the oil, and it just clicked," said McCrory, who used the clippings from his Huntsville salon — and his wife's pantyhose — to develop a prototype.

A few years later, Blacker was running a company in Alabama, World Response Group, that specialized in oil and chemical remediation products when a colleague walked into his office with a matted wad of McCrory's making.

Blacker bought the patent from McCrory — but found the oil industry wasn't interested. Then he started getting calls from growers wanting to buy his product in bulk.

"That blew my mind," said Blacker, who was surprised to learn that hair had a folk-remedy reputation for repelling deer and fertilizing plants.

"It was sort of an old wives' tale," said Blacker. He shut down the business, boned up on the science of hair, and decided to relocate to the Homestead area to be closer to the agricultural industry — and potential customers.

McCrory gave up hairstyling to sell what he used to sweep into the garbage. He also stands to make royalties if SmartGrow takes off.

The company's sales team has been met with a few raised eyebrows.

One grower in North Carolina, after hearing the sales pitch, "asked if he was on Candid Camera," said Mike Foley, executive vice president in charge of sales.

The hair mats recently received certification from the Organic Materials Review Institute allowing it to be used on farms complying with USDA-approved organic methods. Another group of UF scientists at the Gulf Coast Research and Education Center in Balm, Florida, are studying the hair mats' effect on bell peppers, blueberries and other crops.

Palmateer, the UF scientist, is now examining why the mats are increasing plant growth and crop yield.

"It's still one of the unknowns," said Palmateer, who said he's noticed a "significant" increase in the yield of tomato plants grown in containers.

The original use for the mats may be making a comeback, too.

The oil-capturing hair mats, marketed by Blacker's company as Ottimats, were used after an oil spill off the coast of California in November.

A video of activists using the hair mats to swipe the tarry mess off a San Francisco beach has been posted on YouTube.

"It seemed to work pretty well, and it's bio-neutral," said Lance Contreras, San Francisco's operations commander for the clean-up effort.

Which is good news for Blacker, who is considering broadening sales beyond the Southeast to the West Coast.

"Here we are in little ole Florida City," said Blacker. "And we're going to help the world go green."