The idea for the business came to Greg Vetter shortly after a friend swiped a two-liter bottle of his mom's homemade lemon-garlic salad dressing from his refrigerator.

Inspired by the lengths someone would go to for a dressing by "Tessemae," his mom's nickname, Vetter challenged her: If he got Whole Foods to sell the dressing, she would go into business with him.

"She said, 'That's never going to happen,'" he recalled.

Five years later Vetter, 31, is CEO of an Essex-based company — Tessemae's — that makes the top-selling dressing in the produce department at Whole Foods. What started as a mother's ploy to get her three rowdy boys to eat vegetables has grown into a $25 million a year operation making a line-up of dressings, ketchup, mustard, garlic spread and marinades.

Whole Foods carries the whole line-up, Safeway sells all seven salad dressings, and Costco is launching the Soy Ginger flavor dressing, in economy size, later this month.

The dressing maker now employs about 150 full- and part-time workers, including 45 at the "Tree Fort," the nickname given to a manufacturing facility in Essex, with a sales and marketing workforce nationwide.

The brand's growth comes at a time when Americans crave "all natural" products as part of healthier eating trends.

"Everything is moving toward clean eating, whether farm to table or paleo or vegan, people just want unprocessed food, and we make that," Vetter said. "We have a five-year head start on the current food trends."

Five years ago, Vetter brought a romaine salad with his mother's dressing in a Tupperware container to a meeting with a manager of the soon-to-open Whole Foods in Annapolis.

The dressing had no name or packaging, but it was a hit, Vetter said. After a review at Whole Foods' regional level, he was asked to become a store vendor.

He settled on the Tessemae's name, found a bottle distributor, designed and printed labels at a copy center and applied the labels by hand. Meanwhile, his mother whipped up the dressing in her kitchen at home and they handpoured the bottles.

When the store opened in May 2009, the four 12-bottle cases the grocer ordered sold out in 30 minutes, Vetter recalled. He rushed home to help his mom make more and they sold 55 cases in less than a week.

Caught by surprise, the business major from Washington College remembered Googling, "how to be a food manufacturer."

He needed to learn fast. He convinced the owner of Adam's Ribs restaurant in Eastport, whom he knew and who is now an investor, to let Vetter and his mom make salad dressing in the kitchen at night. For two years, they worked 11 p.m. to 5 a.m. shifts on weekends and paid the owner in salad dressing. Vetter also worked full-time as an employee benefits broker in Annapolis, playing professional lacrosse for the Bayhawks and doing in-store demonstrations.

"He and I would be whipping up salad dressing every other weekend," recalled Teresa Vetter, who said she had always made large batches of the dressing for her sons' lacrosse tailgates. But at the restaurant, they would make 50 cases in 24 hours, lining up hundreds of hand-labeled bottles and hand-pouring the mixture, repeating the routine twice a month.

Distribution grew from the Annapolis store to four Whole Foods. In May 2010, Vetter convinced his brother Brian, also a professional lacrosse player, to quit his day job and become Tessemae's general manager. Their mom eventually bowed out.

As sales grew, so did the number of stores, from four to 18 in Maryland, Washington and Northern Virginia, and the varieties of dressing. Whole Foods began supplying products through its mid-Atlantic distribution center, and the store count jumped to 42.

Consumers have been willing to pay a premium for the dressing — it sells for $5.99 a bottle — and put up with having to let it sit out or run it under water before use. Because it's all natural, with no thickening agents, the dressing can congeal when kept cold.

"It's not cheap; it's not easy to use; it's just good for you," said Brian Vetter.

The dressings, which come in seven flavors including the original Lemon Garlic, Cracked Pepper, Zesty Ranch and Soy Ginger, have been a good fit for Whole Foods, which views locally sourced and produced products as core to its business, said Matt Lamoreaux, produce coordinator for Whole Foods Market Mid-Atlantic, in a statement.