Hi Mike, we tried to grow large tomatoes at 5th street in 2018-2021 and ran into the same thing. It's so nice to see a beautiful photo and description of something like a Berkeley Tie-Die (found at Davis Food Co-op) and had high hopes of a delicious heirloom slicer. Who could not resist? We had salt and local olive oil all ready. But nope. In 2021 there were three days in a row when it was 112-114F in Sacramento and Davis and when that happened was that it appeared to have cooked the large nearly ready fruit on the vine. We saw very large amount of the same damage in other plots and then the compost bins filled up quick with burned tomatoes that should have been beautiful. So many beautiful heirloom giant fruit destroyed by the heat. When this happened we noticed that our cherry tomatoes did fine. While we are not pros and kind of just plant by putting the fuzzy end down, try to remember to water and hope for the best, we decided to plant only cherry tomatoes.
For 2023 we visited Morningsun Herb Farm in Vacaville (which is like Disneyland for plant lovers) and picked up 24 types of cherry tomatoes.
Here is their website:
https://morningsunherbfarm.com/
Those 24 plants grew in three raised beds at 5th street like monsters and produced thousands of tomatoes. We were harvesting them by the grocery sacks full, telling other gardeners to please take as many as they can eat and giving them to co-workers at UC Davis and there was no way to use all of them. The heat did not appear to damage many if any of the small fruit. No science involved, just guesswork and watering maybe every three to five days in raised beds with soil from Redwood Barn (
http://redwoodbarn.com/) supplemented with kitchen scraps. Simple cages, no training or even slipping suckers at all. Totally lazy.
This year we went with just 10 cherry tomato plants and this heat as 4PAM has mentioned hasn't damaged them so far. They are producing more than we can eat. If you want to taste sample any of them they are located at plot i6, the password to the green bike chain is the same as the tool shed so help yourself. We have all of the plant tags and can identify them visually. The orange ones are succulent and we have made pasta sauce with those. They crazy looking purple and orange ones are called Brad's Atomic and while they look bizarre they have thick skins so are best suited for a salad where you can chomp down on a whole one and get the juice explosion in the mouth.
I spoke with Diane today who is plot h6 I believe and she is using heat shield canopies and showed me some other examples of their use. Those are apparently working quite well.
There are also other garden plots showing massive success with large tomatoes and I'm trying to ask those people what their secrets are when I can catch them there. We use above ground beds only, just because we got them cheap and they are easier on my back by a bit, but it seems all the huge fruit to be seen now and planted directly in the ground.
In summary, we have found that small cherry tomatoes, in the last five years and with all the heat, simply won't or at least have yet to fail at 5th street. Even with some really questionable and spotty (lazy) watering patterns before we install drip irrigation just this season. Hope that helps.
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