Despite the swirling snow and blustery wind outside, Pat DeFillippo's tomato plant is flourishing. He also is growing basil, rosemary, marjoram, and even, a little fig tree that's just starting to show buds.

DeFillippo owns Home Hydroponics in Lawrenceville, and is never without fresh tomatoes. "Spaghetti sauce at my house is always fresh," he boasted, picking a couple of red plum tomatoes off the vine. "They taste better when you grow them yourself."

Hydroponics is a method of growing plants without soil. In climates with cold winters, it's the best way to cultivate plants, until they can be planted in soil.

"You can grow just about anything that you would grow in your garden," DeFillippo said.

But don't ask him about that. It's no secret that hydroponic machines have been used illegally, to grow marijuana.

"That word never comes up in here, and if they are doing it, they're not getting their supplies from me," DeFillippo said.

Gardeners use the hydroponic machines to start their plants indoors under fluorescent lights during the winter, and then plant them outside when the ground thaws, he said.

It's possible to maintain a hydroponic plant without soil indefinitely, and to re-use the soil substitutes.

At Full Bloom Hydroponics on the South Side, owner Mike Landstrom sells AeroGarden, a starter kit he calls "growing for dummies." AeroGarden comes with a machine the size of a toaster, a packet of seeds, a timer, and the light and irrigation system already installed. Simply plug it in.

"You can set it to different settings for herbs, tomatoes or flowers, and it will time the lights, and keep the right amount of water in the roots," he said. He's already started to see sprouts on basil and chives he started on an AeroGarden in his store a week ago.

"It even comes with a DVD to help you get started," he said. "It's pretty foolproof."

For those who want to build their own hydroponic system, a little research is in order. First, find out how much and what kind of light, and how much water the plant you want to grow needs. The growing medium can be as simple as dried coconut husks. For the novice, DeFillippo recommends rock wool -- rock which is baked at 3,000 degrees, then spun like cotton candy into an almost spongy consistency. "It will hold the roots well, and keep them moist," he said.

A separate power source might be necessary for certain types of lighting systems, DeFillippo added.

Lettuce is a good starter plant for a beginner, Landstrom said. It's easy to grow and maintain, and is ready to harvest in about three weeks.

Landstrom said hydroponic plants grow faster and their roots take up much less space than plants in soil.

The benefits of hydroponic gardening include a lack of pests, a reduced need for pesticides and a longer plant life. "I think they taste better," DeFillippo said of his hydroponic tomatoes.

Other popular hydroponic plants include all variety of herbs and bonsai trees.

DeFillippo said he gets a lot of customers who grow orchids, and Landstrom has a large, purple orchid plant in the entry of his shop. "They are a lot easier to grow than people think," Landstrom said.

"I'm not big on flowers personally, but a lot of people like to get them started now," DeFillippo said. "It's a great hobby in the wintertime, and gets you thinking about the warm weather that's not that far off."
The growth rate on a hydroponic plant is 30-50 percent faster than a soil plant, grown under the same conditions.

The extra oxygen in hydroponic growing mediums helps stimulate root growth, and plants with ample oxygen in the root system absorb nutrients faster. The nutrients in a hydroponic system are mixed with the water and sent directly to the root system, so the plant doesn't have to search in the soil for nutrients. The hydroponic plant requires very little energy to find and break down food, and this saved energy allows the plant to grow faster and produce more fruit.