tomato grafting: a tactic for heirloom success?

ICOUNT TOMATO GRAFTING AMONG MY NEWEST OBSESSIONS. I know, I know; did I need another obsession—and particularly one that offbeat? But after a season of widespread tomato troubles and my generally leery feelings about counting on a plentiful crop from heirlooms in particular, why not considering turning to grafting for an edge? Growing a desired though perhaps less vigorous variety on tougher rootstock has been the trick in many crops (think roses, fruit trees, and many other ornamentals). Tomatoes, it turns out, are no exception. Into the world of grafted tomatoes we go…

It was a recent email from Johnny’s Selected Seed, which sells not just seed for tomato-rootstock varieties but also grafting clips to hold the freshly connected plant parts in place, that piqued my interest.

It alerted me to what is apparently a commonplace tactic in greenhouse tomato production, where soil infected with fusarium, for instance, would otherwise have to sterilized in a costly manner before planting again. By grafting the crop whose fruit you want (called the scion) onto resistant rootstock, you can limit the effects of such troubles as corky root, verticillium, and crown rot, plus most common nematodes—and also just get bigger yields from relatively weak-growing but favorite varieties.

“Grafting is an increasingly popular technique among tomato growers who have had disappointing yields and disease problems,” said the note from Di Cody of Johnny’s. “It’s especially helpful for heirloom, greenhouse, and hoophouse tomatoes.”

The note linked to a 2008 article in the trade publication “Growing for Market,” in which one farmer said: “I will not grow an heirloom tomato that is not grafted anymore,” and that grafted rootstocks are an “heirloom grower’s best friend.”

For heirlooms, choose the tomato rootstock Beaufort, said Di’s email (others are better geared to greenhouse production of hybrids). One thing that scares me, even more than the slice-and-dicing itself with a razor or Exacto knife: the price of seeds for the rootstock. Fifty seeds of ‘Beaufort’ cost $20.95, and I still need the grafting clips. Hmmm…what price tomatoes? But I remain fascinated.

I read about how to graft by three methods in “Grafting Tomatoes,” Johnny’s useful pdf, and watched the University of Vermont Extension how-to grafting video (above).  Soon, in typical Margaret fashion, I started even farther down the research rabbit hole, and was reading things like these:

grafted tomatoesIn Hanoi, where the hot, wet months mean tomato diseases flourish, grafting is a tactic used to produce a valuable cash crop anyhow. In Japan, an Ohio State project reported, about 95 percent of watermelons, oriental melons, greenhouse cucumbers, tomato and eggplant crops are grown as grafts.

Also at Ohio State, there was information (and even a video, up top) of the advantages of grafting for field-grown tomatoes—not just those in the greenhouse. Even Wikipedia has a good page on tomato grafting, with various photos (including the one a bit above).

I even found grafted tomato plants for mail-order sale—but in the UK. So what do you think? Would you try your hand at grafting in the pursuit of a heavy crop of your favorite tomato, or maybe start nudging your local nursery to press for grafted plants from their supplier? I have a bumper crop of sauce in mind over here.

chopped tomatoes for making sauce

83 comments
January 7, 2010

comments

  1. Brian G. says

    That is VERY interesting. How the rootstock protects the grafted plant from pests and disease is a mystery to me (like math). I will definitely have to research this.
    Regarding the cost of the rootstock seeds, if you share with an equally adept gardener or two (or three) you can offset the cost. Even if only one of you are successful, the winner can share good results with the losers.

  2. says

    Wow! Scarcely know where to start. Got interested more or less the way you did, via Johnny’s, in my case by noticing those special seeds. Continued researching, etc. etc. Realized that I was never going to be as punctilious about keeping everything sterile as instructions said the pro’s are. So I decided I’d try it when the plants were pencil thickness, thinking those sturdy stems could be grafted like woody plants and might not be as vulnerable to pathogens.
    Ha! Very difficult to get the two stems to stay put long enough to bind together (have to tie w/rubber band or similar, no clips big enough). Anyway, managed to get 3 grafted plants – out of 13 or 14 tries, time has drawn a merciful veil. Two lived long enough to go into the garden. Where they not long after perished from blight, along with everything else.
    Don’t know if I’ll try again. I did use a disease-resistant hybrid for the rootstock, rather than the $$ seeds. Please let me know if you want to follow Brian’s suggestion and share an order. Also an order of clips, which if I’m remembering right (no catalog handy) come in lots of 1000.

  3. says

    Too much work for a casual gardener like me. If I were marketing tomatoes, maybe I’d give it a try. I have more room available to grow more plants than I have ready cash for the gear. Of course, tomatoes tend to grow really well here — if they didn’t, I might become a “try anything” person!

    And 50 seeds for $20 bucks…well, what would you pay for plants instead of seeds? Probably not so different.

  4. says

    Oh so very interesting. I like Leslie’s idea of using a disease-resistant hybrid or sharing an order of the rootstock seed. Hmmm. I’m taking the Master Gardening class this spring, maybe I can find some folks to experiment with me.

    I want to try the cucumbers, too.

  5. Linda From NC says

    What impact, if any, does grafting have on seed saving from the tomatoes? I think this is intriguing, but as with everything new, so expensive to do at this point for a home gardener. Thanks for the good information.

  6. Susan says

    I was always taught to plant the tomato plants really deep, especially if they had grown leggy under lights waiting for the last frost date to pass (Mother’s Day in our zone). Tomatoes will put out roots all along the stem that is underground, adding strength. I wonder, when you plant grafted tomato plants, is it important to keep the graft joint above soil level? Or, can both the rootstock and the scion put out roots?

    • says

      Welcome, Susan. You bring up a good point…I will go back and watch the videos again and clarify. I think generally you want the rootstock to be doing the rooting tasks, and keep the scion as just the foliage/flowers/fruit machine. But how deep you then plant these is a good question…probably addressed in the Ohio State stuff (video etc.) but I did not pick up on it. More later…

  7. says

    I’ve never grafted tomatoes, but when I was working in Japan and learning to graft magnolia, maples, and cherries, my boss told me a Japanese saying: It takes 500 tries to learn to graft! It isn’t really hard, it just takes a steady hand a confidence to make smooth, even cuts — and lots of practice!

  8. says

    Hi All,
    I am a graduate student at North Carolina State Univ. that has been conducting tomato grafting research team for the last 5 years. As I was scrolling through the comments above, I wanted to add that it is important to keep the scion-rootstock junction above the soil line when planting in order to avoid adventitous roots from forming a bridge from the scion to the soil. The increased soil borne disease protection that grafting provides rests heavily with the genetic make-up of the rootstock (a mix of the common tomato and a wild relative) so you don’t want the scion to form roots allowing the disease causing organisms to jump ship and avoid passing through the root to the shoot. Grafted plants also tend to be more vigorous so be prepared for taller and heavier plants to manage in your garden. You can also experiment using any type of tomato with root qualities you like as a grafting rootstock. We have worked out a grafting protocol that is similar but I believe easier than the one featured in the video above. You can take a look at our methods at my website or by searching ‘grafting heirlooms for disease resistance on the web’ – Have fun!

  9. Eileen says

    Oh no!!!!!!!!!!!!!!!!!!!

    Maxifort and Beaufort rootstock seeds are a product of De Ruiter seeds, which is a part of Monsanto.

    I cannot in good conscience support Monsanto intentionally, even with $20.

    • says

      @Eileen: Thank you for the information. I loathe Monsanto. I will keep looking for other rootstocks. :) Let’s research the origin of ‘Celebrity’ as another commenter recommends…hopefully not from the “M” word.

  10. says

    I learned of this technique from a Master Gardener Specialist training this past summer.

    While it has an expense initially, buying the clips and such, they can be reused and reused. After a while, the cost is minuscule

    The tomato rootstock we use most is ‘Celebrity’. It is very plentiful and cheap here, but I don’t know how available it is in other parts of the country. Seeds are very available at Johnny’s Selected Seeds, or at Totally Tomatoes Seed Company. ‘Celebrity’ is resistant to every impairment known to tomatoes, except one. I will have to look it up to know which is the one exception.
    ‘Celebrity’ is a very sturdy plant. I recommend it.

    The rootstock does not have to be exotic tomatoes. That kind of defeats one of the purposes of my vegetable garden; to deliver safe, fresh food to our table at a reasonable price.

    Also, tomatoes are not the only vegetables grafted. Squash, cucumbers, eggplant, peppers, and others can be grafted. They just take a larger size clip.

    As far as how deep to plant the tomatoes, we graft them in the ground. The rootstock is as deep as it is going to get, when we put the top on it. You don’t want the tops to make root, just as you don’t want the rootstock to put on shoots or suckers.

    I do love this kind of thing.

  11. says

    This is a very interesting topic. Just think… giving heirloom tomatoes at least some disease resistance! I love growing heirlooms, but have began growing more hybrids in recent years due to the lack of disease resistance in heirlooms. Grafting is something I would definitely love to learn more about, but it does bring up one question that I believe another commenter proposed – Will you be able to save the seeds from a grafted tomato plant and still end up with a “true” seed? Perhaps this is something that I will research a bit further. This is a great topic, and thank you for posting about it!

    • says

      Welcome, Tee Riddle. If the rootstock isn’t reproducing (making flowers and setting fruit) then it seems to me that the scion material (the desired crop) is what your seed would be coming from. It’s not as if grafting produces some sexual cross or hybrid; the fruit you get is the fruit you want, and true to its variety, no? I am betting on yes.

  12. Linda From NC says

    Botanical Interests carry Celebrity seeds. I’ve used their seeds before and have never had any problems. Hope this helps. I’m going to give it a try!

  13. says

    Margaret’s (as usual) right. Seed would come true – no worries about unwanted genes somehow migrating up from the rootstock.
    Actually back yet again just to weigh in on Celebrity, in case somebody reading this thread started getting the idea it might be good for something besides rootstock. To quote from my recent post on planning for next year’s tomatoes:
    ” In my 3 years ( I’m a slow learner) of growing ‘Celebrity’, it was always super-dependable. Drought or deluge, disease attack or simple neglect, it made huge numbers of firm, blemish-free, almost perfectly round bright red tomatoes that were as close to tasteless as it’s possible for a fresh fruit to be.

    • says

      @Leslie: Thanks for confirming the role of rootstock vs. scion. The only mishaps with grafted plants I have grown (not tomatoes but woody ornamentals like witch-hazel and crabapples and such…and a common experience with roses when the scion is killed in a harsh winter) is when the rootstock wants to overtake the desired plant. I remember one year when Martha ended up with a lot of red roses that she didn’t plant, because the rootstocks had survived a rough bout of cold and the pink beauties up top hadn’t. Oops.

      I am glad you point out on your blog how even though it’s a “do-er,” ‘Celebrity’ is a “don’t.” Who wants buckets of tasteless fruit? Ugh.

  14. says

    Another source of commercial tomato rootstock (and other veggies) besides DeRuiter in the U.S. is D. Palmer Seeds in AZ. The real trick is to identify what you major soil diseases are and choose a root contributing tomato (doesn’t have to be a commercial rootstock) that has resistance to it. If soil diseases are not a big challenge at your location, grafted tomatoes can still be a benefit with their extra vigorous growth which often leads to a longer season and greater fruit yields. mmm… I can’t wait for a summer tomato right now!

  15. says

    Thanks for the link, Margaret,
    and for emphasizing the issue of rootstock vs scion. I think that may be why pro growers graft their tomatoes when the plants are still tiny threads. Can’t remember for sure, but think – and those first pictures seem to confirm – that you cut the rootstock UNDER (good grief!) the cotyledons, presumably to remove every single node. For what it’s worth, my older rootstocks did keep trying to branch below the graft. Wasn’t a big deal to keep them pruned at the beginning, but it would have been if they’d lived longer.

    NOTE: Leslie corrected this comment (about where to make cut in rootstock) in another comment below.

  16. naomi says

    The uncommon freezing temperatures here killed my potted, two year old, blooming tomato plant, so your post is timely. I’m trying to figure out what heirlooms will make it in my tiny courtyard in humid, hot NOLA. I’ll be checking those links. Love your site; normally I’m a lurker, but this topic is one of great interest to me right now. Thanks for all the information in your posts, and your sidebars. One more day, then I’ll find out how much else died.

  17. says

    I was wrong! Went to the – daunting but exceedingly thorough – instructions at Eileen’s link and learned you make the graft above the cotyledon:
    “Locate the graft union above the cotyledon to prevent adventitious roots from forming and leading to infection of the susceptible scion tissue (Figure 5).”

  18. MichelleB says

    This is fasinating stuff. I was wondering if a determinate rootstock will effect the growth of an indeterminate top? I’ve already ordered my clips and can’t wait to give it a try. Thanks for the information.

  19. MichelleB says

    I emailed Cary, I’ll share information if he responds. I also have a question for Janie. How big were the the plants when you grafted after planting? How did you maintain the total dark and high humidity the 2 days after grafting under field conditions?

    I decided to use MichelleB since there’s already a Michelle here

  20. MichelleB says

    Cary said that the top (scion) seemed to determine the growth of the grafted plant. So an indeterminate heirloom would still be indeterminate.

  21. MichelleB says

    Cary responded yesterday. He said that plant size seems to be determined by the grafted top (the scion) rather than the rootstock. He welcomed any other questions.

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