We had a full house a couple of weeks ago at the Tomato Grafting Workshop, graciously hosted by Tasha Dunning and Greg Berger of Spring Ledge Farm in New London. This was a true “farmer to farmer” workshop where Tasha covered how she grows and grafts tomatoes during the late winter months. Grafting tomatoes has been done for many seasons at Spring Ledge, and it took them a number of years before they dialed in on an efficient and successful system. For those that have tried to graft and failed, or those that are still working out the kinks of their system, Tasha shared a lot of tips for success. Some of the critical ones are listed below, as well as some resources at the bottom!
- Plant rootstocks and scions of different ages so that you are sure to have some plants that are a good match (the same diameter). Tasha suggests starting by seeding Maxifort rootstocks, waiting 3-4 days and then seeding both Maxifort and scion cultivars together, repeating in another 3-4 days, and so on – finishing by seeding scion cultivars alone. Plan on extra plants, even though seed is expensive, so that you have plenty of seedlings of the same stem diameter.
- Tomatoes are ready for grafting when they are 2-3 weeks old (it depends on growing conditions). Compare the stems with your grafting clips to see when they will fit well.
- Remove the top of rootstock and bottom of scion varieties; aim to slice slightly below the cotyledons (seed leaves). Many fact sheets suggest slicing on an angle, but Tasha finds that slicing straight across (horizontally) works just fine and makes it easier to line up the seedlings to get a good union.
- Seedlings should be VERY WELL WATERED before grafting. This helps prevent the scion from drying out before the graft union is healed.
- Don’t graft in direct sunlight. Again, this helps prevent scions from wilting.
- Before grafting, pinch off cotyledons and remove the 1-2 biggest true leaves from the scion (this reduces water needs of the scion, again reducing the chances of wilting).
- Move plants into the healing chamber right after grafting. Tasha waits until she has finished a tray – if you are slower, you may want to move them in more often than this.
- Keep tomatoes in the healing chamber in the dark for 1 day; then turn on lights. The tomatoes are kept in the healing chamber for one week total, and then moved out into the greenhouse.
The healing chamber is a very important part of the process. A photo of the healing chamber at Spring Ledge is shown here. Each layer has fluorescent lights, and a misting system on a timer. Flaps or greenhouse plastic and shadecloth roll down over the front of the chamber to keep it moist and dark inside. The lights inside keep the temperature to be roughly 80-85F.
Here are Tasha’s favorite links for more grafting info, the mister controller, and grafting supplies. For the misting nozzles for the chamber, check out pages 216 & 217 of the Griffin catalog.
A few other resources offering different perspectives on grafting:
Grafting Greenhouse Tomatoes, University of Vermont
Vegetable Grafting: Eggplants & Tomatoes, Washington State University
Tomato Grafting Project, Ohio State University