The First Lady isn’t the only one breaking ground for a vegetable garden this spring. According to a recent survey by the National Gardening Association, an additional seven million households plan to grow their own fruits, herbs and vegetables in 2009, up 19% over last year. Gardeners spent $2.5 billion on seeds, plants and garden supplies in 2008. Now publishers are hoping to channel some of an anticipated increase in spending into how-to gardening books.

Three publishers with strong outdoor titles, all owned by Workman Publishing—Algonquin Books, Storey Publishing and Timber Press—are participating in their first large-scale joint promotion. In May, they will kick off a four-month Get Gardening! tour of independent bookstores across the country. “Our authors will travel the country as gardening evangelists—teaching people how to plant an abundant vegetable garden in a small space and how to create plant combinations that are easy and awe-inspiring,” said Timber publisher Neil Maillet.

To date, more than 15 stores have signed on, starting with an event on May 5 with garden photographer Saxon Holt, Grasses (Storey) and Hardy Succulents(Storey), at Books Inc. in Palo Alto, Calif. Participating authors include Scott Calhoun, owner of Zona Gardens and author of Designer Plant Combinations (Storey), Amy Stewart, author of Wicked Plants(Algonquin), and Lee Reich, author of Uncommon Fruits from Every Garden (Timber).

Even before the promotion begins, Storey has noticed an uptick in sales. “We’ve certainly seen huge sales in our gardening books both in 2008 and so far this year,” said publicity director Amy Greeman. “Ed Smith’s The Vegetable Gardener, first published in 2000, is consistently in the top ten in sales at chain bookstores.” In addition, the press sold out of its first printing of 20,000 copies of The Backyard Homestead (Feb.), edited by Carleen Madigan, in the first four weeks. Storey has gone back to press for another 8,000 copies.