Low 40s is probably not enough to harm them but any possibility of covering them during the cool nights if you don't want to move them just yet? Would your greenhouse have approximately the same light conditions as they are in right now?

Yes in fact they are next to the GHS. I use shade fabric in summer but that is removed now.

I am tempted to wait until I get a lot of leaf drop and then move them. A downside with the GHS is that if we get another day in the 80's like last Saturday it will hit over 90 in the GHS and that might send the wrong signals (time to grow) to the plants. I am looking to harden them off in the most efficient manner.

I also live in the San Francisco Bay Area San Jose to be exact and I am bringing my plants into the greenhouse this week I also use Christmas lights to help keep them warm during the winter in my greenhouse and when the temperatures get too low I use small kerosene heater to keep them warmer I think the days of 80s and 90s are over with last year I put them to bed about the same time and I cut the leaves off some of my plants and they seem to be fine with that

stu I think you have the right timing - I see Monday may rain again and temps hit a low of 39. I haven't used the Christmas lights yet, but have plenty I don't use anymore. I have used a soil heating cable buried in sand under small pots to keep things like coleus alive.

its amazing the difference that overhead cover makes. the last few winters have been milder than whatever normal is so what worked before may have been good fortune...

If plants are dormant they want to be on the dry side. On the other hand, water retains a lot of heat. Gardening is full of paradox's.

I also live in the Bay Area, it's a lot cooler here in Foster City, Stu and Chadinlg, some of my plumerias still have inflos that have unopened buds. Last couple of days has been so windy that I had to move the smaller plants to my covered patio area. This morning at 7:45 was 46. I have been wintering some of them in my south exposure living room and the bigger ones I keep them covered under my patio, close to the door. I'm glad you two are in my zone area and we can exchange notes!!!!

Igschroter and merkity what part of zone 9 are you ?

I myself still have two plants out of 24 that have inflows and are doing great in the greenhous at my house this morning at 7 it was 40 and has gotten down to 36 at its coolest point so far. This is great that there are more people in the Bay Area growing plumerias look forward to chatting with you all

I live in Hayward and have moved all of mine in to my unheated greenhouse now since we got to the low 40's. They're all still blooming!

Same here. cut all the leafs and they are happy inside the greenhouse. from Santa Clara home of 49ers!!!!