Grafted tomatoes give gardeners luscious taste with healthier plants

Published 12:04 am Sunday, June 2, 2013

The great horticulturist Luther Burbank might be astounded with the tomato trend sweeping the world. Many decades ago, he experimented with grafting tomatoes onto potato roots in hopes of creating better disease resistance and fruiting. Now, thanks to efforts of plant breeders in Japan, Europe and Australia, his dream is a reality — by grafting desired varieties onto other very disease resistant tomato roots.

Why bother? Because it’s now possible to enjoy great tasting heirloom varieties like Cherokee Purple, Black Krim, Mortgage Lifter and many more, without many of their common diseases. Now gardeners can have the best of both worlds — luscious taste and much healthier plants.

“Grafting is changing the way America gardens,” said John Bagnasco, horticulturist garden communicator, and a developer of these newcomers, he and his associates are selling as SuperNaturals Mighty ‘Mato.

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He’s so excited about this gardening revolution that he says it’s “my new calling in life.” At his Fallbrook, Calif., home, he has been testing by growing and tasting, more than 36 different grafted tomato varieties. Studies have also been made during the past three years at various university growing grounds in Hawaii and the mainland U.S. The consensus is that grafted tomatoes offer definite advantages.

“Our SuperNaturals grafted vegetables are resistant to soil-borne pathogens and pests and have increased disease resistance including early and late blight and blossom end rot,” Bagnasco said. “Plus they have greater tolerance to environmental stresses such as poor soils and extreme temperatures.”

Thirty-nine different varieties are available at nurseries and various mail order firms. Mail order sources include Burpee, Territorial Seed Company, Gardens Alive and Jung Seed Company.

According to Chelsea Fields, vegetable product manager for Burpee, Inc., grafted tomatoes help gardeners “get disease resistance without sacrificing flavor.”

She supervised testing of 120 different varieties during a four-year period at Burpee’s Doylestown, Pa., gardens.

While she feels they won’t completely replace seed-grown tomatoes, she said, “they are a nice planting tool.”

Here are a few fun varieties:

4 Pink Berkeley Tie-Dye — port-wine colored beefsteak-style (about 8 to12 ounces) with metallic green (turning silver) stripes; possesses a fabulous sweet, rich dark tomato flavor. Indeterminate/70 days to fruit.

4 Jet Setter — Tall, large beefsteak-style. Indeterminate/65 days. Carmello — Smooth red crack-resistant variety is a favorite in European markets for its delicious balance of sugar and acid. Productive even in cooler weather. Indeterminate/75 days.

4 Sun Sugar — Abundant candy-sweet orange cherry tomatoes with high levels of sugar and vitamin A. Indeterminate/60-65.

4 Pineapple — Huge golden beefsteaks, marbled in cherry-red, have mild fruity flavor. Indeterminate.

4 Big Zac — Maybe the biggest tomato of all! This gigantic and very delicious tomato normally reaches 3 lbs., and can reach 5 to 7 lbs., with luscious, meaty fruits growing on a hearty, disease-resistant plant. Indeterminate/85 days.

4 Brandywine — A beloved heirloom from 1885, is problematic because of its tendency to be stingy with fruit and susceptible to diseases. Grafted makes a mighty difference with large, pink beefsteak-type fruits to 2 pounds with intense tomato flavor. Indeterminate/85 days.

How to grow grafted tomatoes

There are several key points in growing these types of tomatoes.

Never plant graft below soil line. Gardeners have been encouraged to transplant conventional tomatoes at least several inches below the soil line so they develop more roots. But this defeats the purpose of buying grafted ones because roots will emerge from the grafted scion. So Bagnasco says place in the ground at the same level as it in the pot.

Trim off suckers and prune back vining Indeterminate types to control their growth.

Be sure to provide strong supports.

Do not overfertilize. Avoid liquid fertilizers such as Miracle Gro because they cause rapid plant growth and discourage fruiting. Fertilize with organics instead. They provide nutrients in the soil that tomatoes absorb as needed.

Insects like hornworms can attack grafted tomatoes. Inspect plants often and pick off and discard them.

Smaller growing, Determinate varieties produce all their fruit in one crop. These varieties can be grown in gardens or containers. Bagnasco advises using containers no smaller than 15-gallon because of their strong root systems.

Water as needed and harvest when fruits are fully ripe to enjoy that just-picked flavor.


Karen Dardick is an Adams County Master Gardener.