I was reading through one of the books that I purchased a while back "gardening when it counts" by Steve Solomon. Its a good book with some useful information, even for those who are more advanced.
Anyway on PG. 37
"For every 10 F increase in temperature, the speed of growth doubles, meaning the size increases from 1 to 2, then to 4, and then 8,16,32, etc."
It is then stated that the biological activity goes on very slowly once the temps are below 50f. I know many have talked about the warmer nights as a main contributor to growth rate. If this growth rate is accurate, it makes me want to get a green house . I have noticed first hand, the slow rate of growth for a 4 month period between mid October and late February in SoCal.
Time to brainstorm ways to increase night time temps passively, besides a green house.