How’s that Tomato Grafting Project Going?


Back in the winter I announced my plans to graft my own tomatoes. I undertook the project more in a spirit of idle curiosity than necessity. We haven’t had the sort of soil problems that might require grafted tomatoes but I thought it would be fun to try.

To graft tomatoes you grow a hardy root stock (I chose Maxifort) and the tomatoes you want to graft them on to. You then make the graft and secure it with a grafting clip. For the grafting process I used the directions in the following video from Cornell University:

The next step is to put the grafted seedlings into a “healing chamber” consisting of a dark, warm and humid environment that gives the plant a chance to heal and the graft to take. You then slowly introduce light over a period of days to transition the grafted plant to normal growing conditions.

What could possibly go wrong?
Let’s just say that at Root Simple Labs mistakes were made.

  • The root stock grew a lot faster than the heirloom tomatoes I chose. When you graft you want similarly sized stems. It would have been good to stagger the days I started my seeds rather than planting them all at one time.
  • The healing chamber needs to be a carefully controlled environment. I improvised a greenhouse by putting my seedlings in plastic bags. This worked but I had trouble re-introducing light in a uniform way. Grow lights would make this easier. And it was a pain to open all the individual bags to mist the plants.
  • Because of my lack of stem sizes to choose from I ended up with graft unions too close to the soil level. Of the six plants that survived my horticultural incompetence, I think they all may just be growing from the graft union itself rather than the root stock. I’m hoping that I can tell when I pull the plants at the end of the season.
  • I used potting soil rather than a seed starting mix. That’s just plain stupid. What was I thinking?
  • Next time I’ll get a selection of grafting clips in different sizes. That would give some flexibility in when to graft the plants.

Despite my cascade of errors I still have tomato plants (though probably not grafted ones) and I learned some valuable lessons should I attempt this project again next year. I’m thinking that instead of tomatoes, which have done fine in our garden in the past, I might try grafting peppers or eggplants which we have had trouble growing.

How are your tomatoes doing this summer? Are any of you growing grafted varieties?

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  1. The deer have eaten everything. The young ones have even learned to stick their heads inside the tall, hog-wire cages to nibble. I’m at a loss, especially since I can’t recall a year with less blight (judging from other people’s tomatoes).

  2. You blog is always great reading and has inspired me in many ways.

    This Spring I grafted a half dozen tomato seedlings onto Supernatural rootstock. For me the challenge comes when the grafted plants come out of the humidity chamber. I lost all but two. Those two were Better Boy and Supersweet 1000 which are already pretty vigorous.

    In my Southwest Washington garden, tomatoes are not bearing yet. I got the first Sungold today. The grafted tomato plants do seem bigger and sturdier compared to others, but the comparison is not scientific. I may have pee-cycled too much, which I say because all of my tomato plants are very lush this year. It remains to be seen if they are more disease resistant during the rainy season, or bear more or larger tomatoes, once they get going.

  3. The grafting tomato thing was always strange to me. I have no problem growing tomatoes (other than occasional blossom end rot on the giant heirlooms) so I never really understood the need. I remember seeing a tomato & potato on one plant in I think the territorial catalogue and thought it was the worst idea ever. But that’s just me.

  4. I haven’t tried grafting tomatoes, but I remember when I used to work in a commercial hydroponic tomato hothouse, if the stem of a plant accidentally got broken, we would tape the surfaces back together by wrapping the stem with ordinary electrical tape. The plant usually survived. These stems were 1/2″ to 3/4″ diameter. (We also used the black tape as band-aids because the owners were too cheap to provide medically approved ones 😛 ).

    Another cool thing tomatoes can do is grow roots anywhere along the stem, so if cutworms cut down some of your plants in the garden, you can root the tops of the plants in a glass of water (with lower leaves removed below the water line). Set the glass in a warm, dimly lit place, and in as little as a week new roots will begin to form. To speed up the rooting process, use willow water in the glass. You can also root large suckers off large plants if you need extra tomato plants.

    How to make willow water:

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