New Grafted Tomatoes Promise Increased Harvests

Last weekend I attended the San Francisco Garden Show and saw a vendor selling grafted tomatoes.  In this posting, I'll describe this new type of tomato and its proposed benefits.

Grafting is the process by which two different plant varieties are fused together.  One variety is chosen for the "root stock" and the other for its fruit, flowers or leaves.  By combining two varieties in this way, it's possible to garner the desired benefits of both varieties in one plant; more specifically, the benefits of a strong root stock (disease and pest resistance, hardiness, growth habit etc.) with the benefits of offered by the second variety (usually type of fruit). 

Grafting is used extensively by fruit growers.  Most dwarf varieties of apples, plums and other fruit are created by grafting the fruiting variety on to a root stock that encourages compact growth.  If you've seen "fruit salad" trees that grow several types of fruit on one tree, these are also created by grafting. 

Below is an illustration of a grafting technique called cleft grafting.  This type of graft is accomplished by cutting off the top of the root stock plant and then creating a vertical slit in the stem. (steps 1-2)  Then the grafted top is cut from the fruiting variety and trimmed so that it is shaped like a wedge.  The wedge is inserted into the vertical slit in the root stock and the two plants are held together with a clip until they have fused together. (Steps 3-4)

Grafted Tomatoes

While at the San Francisco Garden show a few weeks ago, I found a vendor selling the Mighty 'Mato, a grafted tomato.  The root stock is a variety used by commercial growers of hydroponic varieties and is reputed to offer increased vigor, higher yields and resistance to early and late blight and blossom end rot.  Onto this root stock is grafted an indeterminate tomato variety.  Mighty 'Mato grafts include: Green Zebra, Costoluto Genovese, Jetsetter, Sunsugar, Yellow Mortgage Lifter, Momotaro, Big Beef, Brandywine and Pineapple.  Mighty 'Mato can also be double grafted so that two varieties exist on the same root stock. Mighty 'Mato plants can be purchased from Garden Life.com.

Another source for grafted tomatoes is Territorial Seed Company.  They offer grafted Brandywine, Big Beef, San Marzano, Japanese Trifele, and double grafted Sungold/Sweet Million, Koralik/Legend, San Marzano/Viva Italia, and Brandywine Super Marzano.

Neither of these suppliers specifically states which root stocks are being used for their plants.  However, there are a number of common root stocks that are being used commercially for hydroponic tomatoes and it is likely that the root stocks for home gardeners are the same.  Below is a table of common root stocks and their disease resistance properties.

I grow tomatoes in containers and hydroponically.  I will do a non-scientific test of these grafts to determine if they produce better results than non-grafted plants.

If you have grown grafted tomatoes, please leave a comment so we can all learn from your experience.

Comments

[L.D. Johnson]

Sounds like snake oil to me, or at best a novelty for someone. With the extra cost, is it worth it? In a fruit tree the extra cost is spread over many years. I doubt that even they claim twice the production, so why not plant twice as many which should be cheaper and still get more tomatoes?

[H. Mark Delman]

Hi LD, thanks for your opinion. The right approach is to test for yourself and come to your own conclusions. The best results may be for those that grow hydroponically. My understanding is that this is the way it is done in Australia and Japan. I dont have an opinion or vested interest in the outcome.
-PlanterTomato

[Eugene Davis]

I have ordered grafted tomatoes for this season, one from MightyMato and three from Territorial. I will let you know how they do compared to the other, standard tomatoes, which are a combo of purchased plants and seed grown.(they do not ship for a week or two)

The science does support the use of these - it is not at all snake oil. Plus they are really not THAT costly compared to regular greenhouse or big box store plants. We are only talking a 10 buck or so difference. I can't speak for others, but that is pretty insignificant money unless you are buying dozens and dozens of plants.

[Mark Delman]

Thanks for your thoughts on grafted tomatoes. Let me know how it works out for you.

[Laura]

There is also another economical option for gardeners who grow their own tomato plants from seed at Betterheirlooms.com website. Rootstock seed, tube grafting clips (which is slightly easier then cleft grafting) and other supplies for starting and grafting are all available in small quantities.

If you never have problems with soil borne disease or low yield, then LD is right -- it probably isn't worth the time, trouble or extra cost. But heirloom tomatoes can really benefit from grafting for added vigor. Good luck!

[Eugene Davis]

More information on grafted tomatoes. The person that is sending my grafted tomato from Gardenlife.com called just now. It turns out that both Gardenlife and Territorial get their grafted plants from a wholesale greenhouse called log house plants. It is also in Cottage Grove Oregon (same as Territorial).

Also, she mentioned two points of information on grafted tomatoes:

1) They do better with lots of soil as the root growth is mega-vigorous. Small containers will restrict the yield. She said that "whiskey barrel" size for each plant would be OK but much smaller will shrink the yield.

2) They have found that they do much better in the fall. They told me that the same tomatoes, ungrafted, right next to the grafted version were failing last fall, from the cold, while the grafted plants soldiered on much longer.

[Norma]

I live in southern Oregon, can I overwinter a grafted tomato. I plan to cut the plant back and place the root and main stem with the grafted part into a suiteable container and place in an unheated area.

[H. Mark Delman]

Yes, I believe tomatoes are actually perennial. However, they suffer from many diseases and it is probably best to treat them as annuals.

-PlanterTomato

[KHULUMA SPEAK NCUBE]

im glad to hear people talk about the resaerch im trying to do. i think grafted tomato's can resist soil born diseases and blights which are common hear in zambia. please i also need your support during my research(school project). im doing a diploma in horticulture sciences.u can find me on facebook and my user name is KHULUMA SPEAK NCUBE. all the best.

[H. Mark Delman]

Unfortunately, we had some of the worst weather this year -- very cold and rainy. So all of our tomato plants did poorly. It was not possible to determine if the grafted tomatoes did better or worse than standard tomatoes. However, I will try to test them again next year. Good luck with your project and thank you for visiting my web site.