Several mail order plant and seed sources are selling grafted tomatoes this year.

Should you buy grafted tomato plants even though the prices are much higher than ungrafted plants?

If you buy plants locally, you can be assured they’re acclimatized to our area and are not bringing in diseases. Some sources claim the root of the graft may be resistant to soil-borne disease, whereas the top, fruit-bearing part of the plant may have heirloom tomato flavor. “Resistant to” soil-borne disease doesn’t mean the plant cannot or will not get the disease, it’s just resistant.

It is true that many nonhybrid tomatoes haven’t been formally tested for disease resistance, but if they were especially susceptible, folks wouldn’t have saved seeds for generation after generation. It costs money to have plants tested for disease resistance, so it hasn’t been feasible for any seed seller to pay for testing open-pollinated varieties. Also, keep in mind the soil-borne diseases tend to be fungal, such as verticillium and fusarium wilts and damping off, for instance.

Even a grafted tomato cannot withstand curly top virus unless it’s a resistant variety, which is not likely since those tomatoes are not especially tasty. The plant also could come with early blight or any other bacterial disease that’s slow to show up.

A major problem with grafted tomato plants, discovered by Boisean Stella Schneider last year, is that you must plant with the graft above soil line, and if the root system is not sufficiently developed to sustain the plant, it fails to thrive or produce fruit.

If you plant it deeper, the plant above the graft may root and yield its fruit regardless of the root portion of the plant.

If you want a large tomato plant to transplant, buy or grow a large ungrafted plant and plant it as deep as you can. Those bumps along the trunk, when buried, will develop into additional roots, invigorating the plant.

By the way, a “new” grafted plant on the mail order market is said to yield tomatoes above the graft and potatoes below the graft. There have been offers of this kind of plant about once per generation for many years; had it been a successful project, we’d all have been growing it. I think it will yield substandard tomatoes and poor potatoes. If you’re growing for food, don’t bother. If you’re just curious, try it.

•••

I accidentally learned of a new gardening book co-written by Boisean Mary Ann Newcomer, entitled “Rocky Mountain Gardener’s Handbook.” It’s a large paperbacked book with beautiful color photographs, and concise growing instructions on a large number of ornamental and edible plants.

Both Newcomer and co-author John Cretti are knowledgeable and experienced in matters horticultural. They focus on the Rocky Mountain states: Colorado, Wyoming, Utah, Idaho, Montana — and Nevada, for some reason, not part of the Rocky Mountain cordillera — but omitting New Mexico.

Since the book covers a lot of ground, literally, there’s no emphasis on soils disease or destructive insects. All three aspects will vary widely over this geographical expanse, so it’s hard to generalize. Most of this country is high-altitude, and that means, necessarily, very short growing seasons. The time between last frost and first frost in places such as McCall may be only one month, for instance.

This book looks like quite a useful quick reference and a nice gift for gardeners.

Send garden questions to melauter@earthlink.net or Gardening, The Statesman, P.O. Box 40, Boise, ID 83707.