By Alex Markels
Green with tomato envy, Rod Williams stood over a plastic container filled with two tomato plants heavy with red fruit as its owner boasted of his gardening prowess. "He was bragging that he had so many tomatoes he'd been giving them away," recalls the Westminster, Colo., resident, whose backyard plants were far less generous. "It was already August and I only had two measly tomatoes."

Hit the deck. "We're becoming a nation of patio gardeners," says the National Gardening Association's Bruce Butterfield, who notes that the $1.4 billion market for container-gardening products is growing at a 20 percent annual clip, twice as fast as the overall gardening market. On-the-go types love the newfangled, self-watering containers, which only need a drink once or twice a week. For apartment dwellers and older folks with limited mobility, container gardens can grow anywhere there's direct sun--an outdoor deck, a patio, even a windowsill. Propped up on a $15 wheeled plant caddy, they can even be moved around to soak up the most light.

Such advantages inspired horticulturist Rose Marie Nichols McGee and her late mother to experiment with containers. An accomplished gardener, McGee's mom had trouble navigating the stairs to her Albany, Ore., backyard because of severe arthritis. "We set up a container garden on her deck," says McGee. Soon her mother was harvesting strawberries, tomatoes, and herbs. "People would come along and say, `Oh, she's still such a great gardener.' "

"Anything that can be grown in the ground can be grown in a container," says McGee, who used her mother's deck to test container-gardening techniques. She published her findings last year in McGee & Stuckey's Bountiful Container: A Container Garden of Vegetables, Herbs, Fruits, and Edible Flowers.

Bigger is better, says McGee. The largest container possible lets the plant grow deeper roots to soak up water and nutrients. She also likes lightweight potting soil (better for root growth and oxygen) and time-released fertilizer. Because container plants depend on you for water, use self-watering containers or drip-watering systems that can be hooked to an automatic timer. "These are great little gadgets," McGee says of the digital water timers and other automatic systems. "Once you set them up, you can pretty much leave them be all summer and never worry about coming back from a weekend away to find your plants wilted."

Container gardening has its own set of dilemmas. Wondering what kind of beans would best climb a ladder to her Brooklyn apartment's roof, Cheryl Willems put out a call on a gardening forum--gardenweb.com. She received a slew of suggestions that helped her choose a suitable scarlet runner.

But you needn't work too hard to succeed. New to his New Jersey neighborhood, Harry Green put his ZIP code in the "Floracle" survey at windowbox.com. For both a sunny and shady sill, the suggestion was petunias. "The guy next door is impressed with how much I've fixed up the house so far," says Green. "And I'm thinking, `That's pretty cool,'cause all I did was put up those window boxes.' "

Our flowers and plants won't feel boxed in by these containers.

Self-Watering Tomato Success Kit includes a rectangular, self-watering planter as well as container-friendly soil mix, organic fertilizer, booster mulch, and tomato support cage. $65. www.gardeners.com; (800) 427-3363.

DIG Battery Timer can be programmed to water one to four times daily, using a 9-volt battery. $40. www.dripworksusa.com; (800) 522-3747.

Windsor flower box planters can be custom fit to any windowsill over 18 inches. $90 and up. www.windowbox.com; (888) 427-3362.

High-rise ceramic strawberry pot features six ascending nooks. Berries or herbs tumble down over the edges. $48. www.smithandhawken.com; (800) 940-1170.

Zinc planters add Eurostyle. The plant sits in an insert that can be pulled out for watering. $49-$169. www.restorationhardware.com; (800) 762-1005. -Alex Markels