By KRISTINA SHEVORY

Given the chance to accompany a team of botanists on a plant-collecting expedition to South America, most gardeners would probably be satisfied with the experience. They wouldn’t come home and try to recreate the rain forest in Manhattan.

But Michael Riley isn’t like most gardeners. Mr. Riley, a former commodities trader turned plant expert who went on to become assistant director of the Horticultural Society of New York, was eager to move beyond potted plants in a way that hadn’t yet occurred to many others. It took a number of expeditions, a lot of research and more than a decade and a half, but by 2003 he had figured out how to grow a wall of plants inside his Manhattan apartment.

“In the rain forest, I realized that plants didn’t need to grow in pots with labels,” said Mr. Riley, 64. “I wanted to grow plants in ways that were natural to them.”

These days, Mr. Riley’s project isn’t that unusual. Vertical gardens - which began as an experiment in 1988 by Patrick Blanc, a French botanist intent on creating a garden without dirt - are becoming increasingly popular at home. Avid and aspiring gardeners are taking another look at their walls and noticing something new: more space. And a number of companies are selling ready-made systems and all-in-one kits for gardeners like Mr. Riley who want to do it themselves.

In the last few years, companies that sell green wall supplies have seen a jump in sales. ELT, an Ontario company that specializes in green roofs, began selling living wall systems a little over three years ago and is now one of the biggest suppliers to the United States. Greg Garner, the company’s president, said that its green-wall sales have increased 300 percent since 2008.

“We’ve turned living walls into something anyone can do,” Mr. Garner said. “The walls have gone from zero percent of our business leads to 80 percent of our business, and it’s happening all over the place, from the Middle East to North America to Europe.”

Many of the modular systems - essentially plastic trays filled with dirt and attached to a wall, with a sprinkler or drip irrigation system installed above - differ dramatically from Patrick Blanc’s living walls, which can be seen in commercial and institutional buildings around the world, including the Athenaeum hotel in London and the Musee du Quai Branly in Paris.

Peter Kastan, an unemployed movie location scout in Miami, had never grown anything when he decided to install a vertical garden in a friend’s loft. The apartment, which his friend offered to him as a laboratory since it was vacant and he couldn’t rent it, had abundant light and high ceilings, and Mr. Kastan, after reading about Mr. Blanc’s living gardens online, thought it would be an ideal environment.

He contacted living-wall creators around the world for advice, and then drove all over Florida visiting nurseries to find plants. He bought 650, including bromeliads, hoyas, begonias and ferns, favoring those that were local and “the most interesting to look at,” he said. And one weekend last November, he and his wife, Mai Tran, and a friend put up the 3.7-meter-by-3.7-meter plant wall.

Kastan used matting affixed to a metal frame bolted to the wall. He bought most of the materials from local hardware stores or online suppliers. About $10,000 later, he has a large, vibrant green wall. He recently completed a smaller one in the kitchen, with herbs and mini-tomatoes.

But it took a lot of work to get the irrigation, the lighting and the plants right. The first month, he lost several plants near the bottom of the wall, where water was collecting. He realized then that some plants were getting too much water and needed to be moved to a different spot on the wall; others he had to get rid of.

“It’s like having a large poodle,” Mr. Kastan said. “You have to take care of it, feed it, walk it. It’s intensive care for plants.”