A small but increasing number of growers have found that grafting a desirable scion tomato variety onto a hearty rootstock helps them manage disease without fumigation.

One Pennsylvania farmer using high tunnels boosted his yields by 20 percent through grafting, according to a news release. A North Carolina State University researcher determined that grafting organic and heirloom varieties can increase profits by 38 cents per plant.

Organic and heirloom varieties are well-suited to the technique because growers can't use conventional pesticides in organic production.

Heirloom varieties originally weren't bred with disease resistance in mind.

In a trial in western North Carolina, 100 percent of the plants grafted onto a rootstock resistant to bacterial wilt survived whereas 90 percent of the ungrafted plants died.

In addition, yields of the grafted plants were twice as much as from the surviving ungrafted plants.

To help growers and researchers learn how to graft, the U.S. Department of Agriculture's Sustainable Agriculture Research and Education program released a new fact sheet.

The sheet includes step-by-step grafting techniques, instructions for building ahealing chamber and an economic analysis of grafting under different conditions.