As I learned from my reading, vegetables may be grafted onto a different rootstock to improve resistance to soil-borne diseases or to encourage more vigorous roots. This year several catalogs are offering grafted vegetables. Members of the nightshade family (tomatoes, eggplants, peppers) are being grafted, as are cantaloupes, cucumbers and watermelon. The grafting is done when the seedlings are still young.
Grafting is done largely by professional greenhouse operators and large field-crop producers. This year, many of the seed and plant catalogs are carrying the grafting materials and grafted plants. I thought about trying to graft some tomatoes, but the rootstock tomatoes are varieties I have never heard of. In some cases, two different tomato varieties are grafted onto one rootstock, a boon for the small-space gardener.
Last spring, I ordered three grafted tomatoes: ‘Japanese Trifle,' ‘Roman Stripe' and a third one whose name I have misplaced. The ‘Japanese Trifle' tomatoes ripened at the end of August and were excellent. ‘Roman Stripe' also was excellent, ripening its first fruit on September 8. The third variety finally had ripe fruit on September 10, but it was not tasty, and the plant itself limped along and turned brown.
I planted all three in a bed separate from my other tomatoes. Before planting, I laid black plastic on the soil to keep it warm and moist, then made holes for the plants. I put up tomato cages and, after planting the tomatoes, put Bubble Wrap around the cages. In fact I put Bubble Wrap around all my tomato cages to capture heat during the day and keep cooling breezes away from the plants at night. I secured this insulation with clothespins. Until the top leaves peeked over the plastic and flowers were blooming, I left the wrap in place.
I was so taken with the taste of ‘Japanese Trifle' and ‘Roman Stripe' that I saved seeds from them to plant this year. The tiny seedlings are just showing through the top of the soil mix.
One catalog (Johnny's Selected Seeds) compares the yield of grafted to non-grafted tomatoes grown in a hoop house. The grafted plants produced as much as 30 percent to 50 percent more over the season than non-grafted plants grown in the same area.
The process of grafting vegetables for improved yield started in Europe and Asia and has now spread to the United States. The University of Washington has published a paper (cru.cahe.wsu.edu/CEPublications/FS052E/FS052E.pdf) that explains in detail the different types of grafts used on tomatoes and eggplants. If you are an experimenter like I am, you might want to try it.
This summer, I plan to grow a grafted eggplant and my own ‘Rosa Blanca' eggplant from seed. I've also ordered a grafted green bell pepper and will grow a similar bell pepper next to it. Then I can determine by my own independent, if not necessarily scientific, test whether the grafted vegetables produce more and better fruit.
If you are interested in trying grafted vegetables, order them soon. Nurseries have cut-off dates for shipping, and you must order about six weeks before the delivery date. Search online for grafted tomatoes and you will find many choices. These plants are more expensive, but remember, you're doing research.
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. Napa County Master Gardeners (http://napamg.ucanr.edu) are available to answer gardening questions in person or by phone, Monday, Wednesday and Friday, 9 a.m. to Noon, at the U. C. Cooperative Extension office, 1710 Soscol Avenue, Suite 4, Napa, 707-253-4143, or from outside City of Napa toll-free at 877-279-3065. Or e-mail your garden questions by following the guidelines on our web site. Top navigation link - Garden Questions?
