ROY -- Rick Madsen figures you can grow just about all the vegetables your family would ever eat and do it without stepping outside the walls of your own home.

Two or three kinds of lettuce in the front room, maybe? How about a crop of tomatoes and radishes in the kitchen?Add some cucumber and zucchini squash in the family room. Any other herbs or vegetables you may need could be raised in the basement or under a stair.

Madsen figures this because he's already growing a bumper crop of fresh veggies inside his Roy pet store, Fantasy Aquarium at 5508 S. 1900 West, using hydroponic gardening techniques -- a method of growing plants without soil, generally using chemical nutrients.

Not only is he growing green food for the store's own veggie-munching critters, but there's always enough left over for a nice green salad at lunch time for himself and store workers.

And in a few weeks, he'll be able to pop a spaghetti squash in the microwave oven or "nuke" some red cabbage or Brussels sprouts in case he has to work late.

Granted, it does sound strange.

A pet store, of all things, where home hydroponics growing kits are sold alongside a full inventory of kangaroos, albino boa constrictors, fish, rats, bearded dragons, hamsters and Savannah monitors.

But for Madsen, a free-thinking '60s-child kind of a guy with long, gray hair gathered behind his head by a rubber band, it just makes good business sense.

As far as he's been able to determine from telephone books and talks with major national hydroponics suppliers, there aren't any other Utah retailers selling home hydroponic systems.

So pet store, schmett store.

Madsen has just renamed his business "Fantasy Aquarium and Hydroponic Gardening."

"You can grow a hydroponics garden in your house 365 days a year," says the pet shop owner, who began dabbling in growing his own food without soil about four years ago.

"I like the idea of eating freshly grown tomatoes in January . . . but I don't like California tomatoes," said Madsen. "And why should I buy food for my animals when I can grow it?"

Hydroponics may be one of the world's oldest agricultural sciences. The Hanging Gardens of Babylon and the Aztec floating gardens are believed to have used hydroponic-type techniques.

In modern times, however, hydroponics gardening has been a viable method of raising food since the 1930s when the University of California began researching how to grow food with chemicals instead of soil.

Large commercial greenhouses have been selling hydroponically grown vegetables to food stores for years, but Madsen says home hydroponics is still relatively new in the Beehive State.

"Basically, you can set up a hydroponic garden for anywhere from $100 to $1,200 depending on the size, the kind of light used and the system," he said. "There are a lot of variables."

There are floor-space-saving vertical systems that can be attached to a wall. Rectangular horizontal layouts, like the one in the front of Madsen's pet store, are more conventional looking.

Madsen's 2-by-4-foot layout is deceptive, however, because it is packed with "growth sites" now busily producing Romaine lettuce, Swiss chard, ruby lettuce, tomatoes, cherry tomatoes, red cabbage, Brussels sprouts, spaghetti squash, kohlrabi, cucumbers and banana squash.

"The yield, compared with food grown in the soil, is astronomical," he said.

Each site is served by a PVC pipe that carries a plant nutrient mixture pumped from a plastic reservoir below the system, using a timer to determine when the mixture is supplied to the plants, potted in a gravel-type material.

In the back of the pet store is a second 2-by-5-foot hydroponic system where Madsen is growing okra, more lettuce and cabbage, and a loofah plant.

Loofah plant? "Yes," said Madsen, "we're even growing our own sponges. Why not?"

Whether his new business endeavor takes off or not, Madsen will continue to grow his own food and experiment with different kinds of lighting and other hydroponic technology.

He also figures it's probably a no-lose proposition, given the public concern over the so-called Y2K problems that many fear will accompany the arrival of a new millennium.

"Hyrdoponic gardening can be done without electrical power or by using standard electricity and 12-volt power sources," Madsen said. "And you don't have to use special hydroponic seeds, either.

If things fall apart in the year 2000, he said, "you're not going to lose your garden."