Just add water

No breeze blows, no birds chirp, and there is no earth to root in. But the two greenhouses on Hayden Rowe Street in Hopkinton are full of life. Beefsteak tomato plants are lined up like soldiers, loaded with blushing fruit.

The plants are being grown hydroponically, nourished by nutrient-rich water -- rather than soil -- in an environment that is carefully controlled, right down to the bees that are shipped in to pollinate them.

While heavy rains this growing season have caused problems for some farmers, it's been business as usual for American Hydroponics Inc., which annually produces about 350,000 tomatoes, or 180,000 pounds.

Most hydroponically grown food is produced in Colorado, Arizona, and New Mexico. Hopkinton residents Jeffrey Barton and Phil Todaro, owners of American Hydroponics, were determined to produce tomatoes that would have a shorter trip to local consumers' tables.

The two 43-year-olds have been producing the tomatoes for the past nine years. The operation makes a profit, they say, but not enough to let them quit their day jobs.

The idea for the company germinated when Barton took a trip to Disney World. He came back with a Mickey Mouse T-shirt and a business plan.

While spending the afternoon at Disney's EPCOT Center, Barton and his family toured the ``Living with the Land" exhibit, a display that includes a discussion of the science and techniques involved in hydroponics.

Barton was fascinated, and upon returning home shared his enthusiasm with Todaro, a childhood friend from Westport, Conn. The two had frequently spoken about starting a business together and had come close a few years before, when they toyed with technology that creates pellets for wood stoves out of waste cardboard. This hydroponics idea, they believed, was too interesting and doable to drop.

The friends flew to Arizona to take part in a weeklong class given by Merle Jensen, a retired professor from the University of Arizona who was the creator of the EPCOT exhibit.

Two and a half months later, after taking out loans, mortgaging their homes, and getting financial help from a friend, Barton and Todaro coordinated construction of the first greenhouse, which had 6,000 square feet of growing area. The first crop was harvested 3 1/2 months later.

As with any new venture, there were some unexpected adventures. When the partners were attaching the flexible plastic greenhouse roof, a breeze nearly lifted them both off their ladders and into the air.

And when Barton went to pick up the cardboard box containing their first beehive, he worried that the bees would get loose.

``I drove to Providence airport's cargo area to get the hive and placed it next to me in the front seat of the car. Listening to the frantic buzzing was very unnerving," Barton said.

New hives must be purchased every six weeks or so at a cost of $300. Fortunately, after nearly a decade, the partners have only one sting to report.

Another day, when Barton and Todaro went to check on the tomatoes, they noticed a few whiteflies buzzing around. He and Todaro had been warned about the pest in their Arizona course, but they figured it was no big deal.

``Two days later, when we went into the greenhouse to look, we felt as if they were picking us up and throwing us out," said Barton. ``There were so many whiteflies that we lost the crop."

Now, Barton and Todaro, whose operation is pesticide-free, use a species of parasitic wasps, Encarsia formosa, to control the whiteflies.

``We hang small packages of the tiny wasps on the plants preventively, they lay their eggs on the whitefly, and, when the larvae hatch, they eat the whitefly from the inside out," Barton said.

For the first three years, both men's families would gather to pick and package the tomatoes.

Now, the company has two greenhouses with 24,000 square feet of growing space and during peak season has six employees.

The process of growing tomatoes begins in a 20-foot-by-30-foot area in Todaro's basement, where humidifiers run to control the environment.

Barton and Todaro start the plants from seeds in 1-inch rockwool cubes, a type of volcanic rock that is melted and then spun into a substance that resembles cotton candy.

Rockwool has no nutritional value, but is very porous, which is important because the cubes hold the nutrient-filled water while giving plants a place to sink their roots.

After about a week, the first leaves begin to show. After two weeks, the plants are transferred to 4-inch rockwool cubes. As the seedlings mature, they are transferred to larger slabs of rockwool. The water in the slabs is tweaked nearly every day to keep the nutrients at the proper level.

One advantage of hydroponics is ``that we can mix the nutrient recipe to exactly what the plants need," said Barton. If the tomatoes are showing signs of yellow, for example, potassium level needs to be boosted. Sweetness and acidity can also be controlled by adjusting nutrients.

Readings from a temperature gauge, humidity gauge, and light meter all feed into a computer program that determines what minerals the plants need, the proper time to feed them, and whether cooling fans or heaters must be turned on.

On a very sunny day, when the plants give off more water vapor, they're fed nearly twice as much as on a cloudy day.

One of the challenges in hydroponic farming is maintaining greenhouse temperatures, which ideally should be kept in the low 70s. ``We don't want it to go much above 80 degrees or below 60 degrees," Barton said.

When temperatures rise above 80 degrees, the back wall of each greenhouse opens and a cooling system, called a wetwall, is activated. The wetwall is constructed of perforated cardboard covered by a waterproof film. Water runs down the wall, while air is pulled through it by a powerful fan.

While American Hydroponics produces tomatoes throughout the winter months as well, Barton says the production then is nowhere near their summer crop.

``Just as we would love to buy more lights and another eight bays, it's the funds right now," he said.

The cost of heating the greenhouse in the winter runs $10,000 per month.

The partners now have natural gas fueling their heaters, but during the first winter of operation they used propane. They ran out one night when the temperature dropped to zero.

``Phil called at 10 p.m. to say, `You're not going to believe this, but we're out of propane,' " Barton said. They summoned an emergency propane delivery, which arrived by 1 a.m., allowing them to blast the greenhouse with heat and save the crop.

The weather is so temperate inside the greenhouses in the winter that Barton has been known to head into them with a lawn chair and a magazine.

Now that they have the greenhouses built, the science down, and a strong client base, they are hoping to be certified as organic. According to Don Franczyk, with Bay State Organic Certifiers, even though the tomatoes are grown without pesticides, they cannot be labeled organic because they are grown in rockwool, which, he said, is partially a synthetic product.

But Barton said, ``We educate the retailers who educate the customers that we're pesticide-free."

Barton laughs as he recalls the early years, which he describes as a time of trial and error for the ``horticulturally challenged" partners.

Now, they've accomplished their goal of bringing fresh tomatoes to local consumers, making some money, and helping the environment.

Next on the wish list, the partners would like to expand into growing lettuce and peppers.

``We've always wanted to grow a salad," Barton said.