Years ago when we were living in Martinez (zone 15), we had a Thompson grape. It was rather old and we were building a shop and so decided we would take the grape out....but it bore so well that we ended up building the shop around it...literally.

Thanks for posting. For the grape experts here, I have a question: does it take weather nearing 90 deg for grapes to blossom or is this more due to the vine becoming ready to bear?

Also, a local nurseryman told me that Flame will do well here. I have planted Perlette based on information that it needs "less heat" than others. I tried researching for temperatures optimal for each variety but only could get vague mentions of "hot summers" and "less heat" etc. Exactly what range of temperatures is required to ripen them optimally?

Congratulations. I had Flame and Perlette on an arbor, but I finally managed to kill them. A friend has Perlette on her back slope and it gets hundreds of bunches- more than all of the birds can eat. Amazing. They are sweet as can be, too. She lives in the San Fernando Valley.
Renee

Our red flame seedless looks to be loaded this year, and it produced pretty heavily last year. We've now got grape trellis halfway around the house.

Took a bunch of cuttings that are pretty well rooted and leafing out nicely if anyone is interested. We are in Tujunga, north central L.A.