Upside-down gardening, primarily of leggy crops like tomatoes, cucumbers and peppers, is more common partly because of the ubiquity of Topsy Turvy planters, which are breathlessly advertised on television and have prominent placement at retailers like Wal-Mart, Walgreens and Bed Bath & Beyond. According to the company that licenses the product, Allstar Products Group in Hawthorne, N.Y., sales this year are twice last year’s, with 20 million sold since the planter’s invention in 2005. Not to be outdone, Gardener’s Supply and Plow & Hearth recently began selling rival upside-down planters. “Upside-down gardening is definitely a phenomenon,” said Steve Wagner, senior product manager for Plow & Hearth.

Image Donald Rutledge, in New Braunfels, Tex., put his buckets on pulleys to protect his plants from deer. Credit... Erich Schlegel for The New York Times

The advantages of upside-down gardening are many: it saves space; there is no need for stakes or cages; it foils pests and fungus; there are fewer, if any, weeds; there is efficient delivery of water and nutrients thanks to gravity; and it allows for greater air circulation and sunlight exposure.

While there are skeptics, proponents say the proof is in the produce.

Tomato and jalapeño seedlings sprout from upside-down planters fashioned out of milk jugs and soda bottles that hang from the fence surrounding the Redmond, Wash., yard of Shawn Verrall, a Microsoft software tester who blogs about gardening at Cheapvegetablegardener.com. Mr. Verrall turned to upside-down gardening last summer as an experiment.

“I put one tomato plant in the ground and one upside down, and the one in the ground died,” he said. The other tomato did so well, he planted a jalapeño upside down, too, and it was more prolific than the one he had in the ground. “The plants seem to stay healthier upside down if you water them enough, and it’s a great way to go if you have limited space,” he said.

While horticulturists, agronomists and plant scientists agree that pests and blight are less likely to damage crops suspended in the air, they said they are unsure whether growing them upside down rather than right-side up will yield better results.