The urge to grow plants, especially ones that feed us, can be charted back to ancient peoples recording their efforts on cave walls, and yet it’s annually new — visible in the delight of a child making daily visits to the garden to discover the first pea vines poking up through the cold soil. Perhaps it’s no surprise, then, to see increasing numbers of urban people turning back to growing edible gardens as a way to reconnect with their roots.

“Each year, the vegetable gardening keeps getting stronger,” says Cyle Eldred, long-time show designer for the Northwest Flower & Garden Show, the second largest such show in the U.S. (behind one in Philadelphia). “I think it’s the future of gardening for the X and Y generations.”

The 22-year-old show fills the Washington State Convention & Trade Center Wednesday through Sunday (Feb. 3-7). Purchased last year by O’Loughlin Trade Shows of Portland from founder Duane Kelly, the show reflects the regenerated interest in “edibles.” The trend will be fed in display gardens such as “A Family’s Little Farm in the City,” unusual exhibits including an old pickup converted entirely into a vegetable garden (vegetables in the engine compartment and bed, chickens in the cab), and in a host of seminars on various aspects of growing your own food.

“Functionality” is one of the show’s themes. Beauty is the other, and elegant fantasy gardens, replete with massive stones and water features, will certainly draw crowds as in years past.

But last year, Eldred says, industry contacts told him “vegetable seed sales were way up, up to 30 percent depending on who you’re talking to.” Nurseries told him “the vegetable starts just fly off the shelves when the season gets going.” In Seattle, new land is being sought for P-Patch community gardens, existing ones have long waiting lists, and similar demand spikes have been seen by organizations that offer food gardening classes.

The maritime Northwest, with a climate conducive to year-round gardening, might be boosting that trend.

“By every Gallup poll I see, the average size of the vegetable garden continues to decline,” observes Roger Swain, well-known author, former host of public television’s "The Victory Garden," and one of three judges for this year’s display gardens. But he also notes a “perfect storm of interest” caused by such things as the slow food movement, “food scares” over tainted produce that sickens people and the urge to reduce the carbon footprint.

“I try to remind people that raising things to eat is why we started in horticulture,” Swain says. “One of the reasons it’s so satisfying is that it’s an ancient ritual.”

One national study shows that more than one-third of gardeners grow food, and more new gardeners are trying it. The annual survey by the Garden Writers Association found that 38 percent of U.S. households (41.6 million) grew a vegetable garden in 2009, and 7 percent of those were new to growing edibles. Moreover, 37 percent of respondents said they planned to increase their edible-garden space in 2010.

“We’re trying to make it so not only the new gardener but the casual gardener can come to the show and take something away from it,” says Terry O’Loughlin, show manager.

“I’m a perfect example,” he says. “Last year we started a 10-by-20-foot vegetable garden ourselves,” and his kids, 5 and 8 years old, “went out and checked it every day.” This year, he says, “I want to learn how to grow pumpkins.”

The inter-generational act of sowing and growing is another aspect that he wants the show to provide, he says. “We want the parents and the kids to come together.”

Two changes to the show, which O’Loughlin notes has a “passionate” following, are to attract those kids with an interactive live butterfly exhibit, and to coax their parents into bringing them along by offering free entry for kids up to age 12, up from age 5 in previous years. Teens up to age 17 get in for $5.

“When do you want somebody to learn about gardening and their yard?” he asks. “When they’re 28 and have just bought their first house?” Rather, he says, “The yard, the garden, the flowers should be a family event.”

O’Loughlin says he was “most surprised by the passion that people have around this show,” and that when his company bought it, “people were expecting big changes.” Attendees come by buses from B.C., fly here from Arizona, and flock to it by the tens of thousands, and he says “this show belongs to the public. I think it’s wrong to change the show.”

Support from the area gardening industry was equally meaningful to him. In the ownership transfer, Kelly told O’Loughlin that more than 80 nurseries helped pre-sell tickets to the show. “I thought it would be OK if I could do half of that, because they’ll look at me and say, ‘Who are you?’” he recalls. “And yet, we did the same. The second the word got out that the show was going to happen, the phone rang and rang for two weeks.” From a business standpoint, he said, that validated the purchase.

The fourth-generation company operates 14 shows in the West, including the Portland Home and Garden Show, with which they’ve been involved for 46 years, and the Tacoma Home and Garden Show. So he expects the “economies of scale” to help him make it profitable, whereas Kelly found the profits dwindling, and pointed to aging Baby Boomer gardeners who just aren’t as engaged in the show — or spending as much — as in the past.

Hence the butterflies and the edibles.

“The boomers were about the aesthetics,” says Eldred. “The X and Y generations are about pulling food out of your garden, having your friends over. Vegetables are just more entertaining.”

Eldred is seeing the trend in his own family. His 18-year-old daughter just started at the University of Washington and moved into a house with four friends. “She’s asking me about getting her compost going, wants to get worms out of my worm bin, and wants to know about getting soil for her vegetable garden.”

Perhaps if her dad’s too busy for that advice right now, she should get a ticket to the garden show.

If you go: The Northwest Flower & Garden Show runs Wednesday through Sunday (Feb. 3-7) at the Washington State Convention & Trade Center, 800 Convention Place, Seattle. Hours are 9 am-8 pm through Saturday, 9 am-6 pm Sunday.

Highlights: Six display gardens will feature edibles, and 124 seminars and how-to demonstrations will be spread over the show’s five days, including 73 sessions for new gardeners, 33 “green living" seminars and 26 edible garden seminars. One session, Thursday evening, will teach how to feed fresh veggies to a family of four all summer for $25. A complete seminar schedule is available here.