The 2022 grafted tomato experiment has just about come to an end. Unfortunately, like many parts of the country, we had an unusually hot summer. We set an all-time record high temperature in Sacramento. It is generally pretty hot here without setting all-time records so I'd describe the summer as "sweaty."
In general, the grafted tomatoes did pretty well in growing the plants despite their late start and less than optimum planting location. I had grafted different heirloom varieties on the rootstocks and noted one variety did not perform as well as the others. That variety was "Mexico." Although those plants grew well, there was some unidentified malady that made the stems turn a somewhat dark color and some branches to die back. The plants didn't die, but they didn't thrive as well as the others. Interestingly, the two Mexico scions were grafted to two different rootstocks, so it appears to be the scion variety rather than the rootstock variety. I'll skip that variety next year.
Even with the hot summer, the grafted tomatoes grew into nice tomato plants, but set very few tomatoes. The Master Gardeners informed me that tomato pollen goes sterile above 90 degrees, and speculated that was likely the problem. When temperatures finally dropped below triple digits, the tomatoes started setting fruit. But the plants had been through the wringer and were not doing well as October approached.
I examined the plants and if it looked like the plant didn't have a chance of producing an edible tomato before cool fall temperatures arrived I pulled the plant rather than continue irrigating. (We are encouraged to minimize water use with our extended drought.) At this point (November 2) I only have one tomato plant left. It has some pretty nice tomatoes on it and I'm hoping they develop enough that I'll be able to pick them and ripen them in the house if needed.
I also grew many of the same heirloom varieties without a grafted rootstock. It is hard to make a direct comparison because of several variables (planting date, soil quality, cage used, etc.) but I believe the grafted tomatoes were healthier overall than the nongrafted tomatoes. I also experimented with planting two tomatoes in the same hole and that had mixed success. It worked fine for cherry tomatoes, not as well for larger sized tomatoes.
So the grafted tomato experiment was a mixed bag. I greatly improved my grafting technique this year, I will get the rootstocks and scions started earlier next year, I'll avoid the Mexico variety, and I'll keep slugging away at it. I'm going to give the grafted tomatoes another try. Next year is just around the corner. We already got our first seed catalog! Which is horrifying and exciting.
