Bear--I wanted to mention also, that little seedlings are just like little kids--most times they just don't want to go to sleep! First year seedings will almost always stay growing a quite a bit longer than their parents and elders. Sometimes they need to be encouraged a little to put them in sleep mode. And exactly when that is becomes a judgement call that only you can make. I'll refer to the pictures of my seedlings in the greenhouse above. I put those in the greenhouse on Oct. 7th with a starting minimum nightime temp. of 55'F. letting daytime temps to reach about 75-80' F. I lowered the nightime temperature 5' F each week while daytime temps fell to 55-60. A week before those pictures were taken, I had the nightime mininum at 38-40'F. Based on what I saw last Sunday and the pictures show, I pulled the plug on the heater and opened the windows for good and in three weeks those leaves should be dry enough for me to almost blow them away. I really believe it's night time temps below 40'F within the next three weeks that will put them to sleep for good. Anticipating my timeframe, that puts me right around Dec 1st when I tip the pots and store them. That's right on target for me here.
During the time in the greenhouse it is visually evident what Rick says about the relationship of lowering the temp vs moisture relationship. Its one you can actually see at the soil surface. I see it even with each 5' drop. and is most apparent the first morning after the drop. Also, as Rick says, those in the picture and the ones you have could just as well go under a roofed over porch, etc. for the next three weeks or so for conditioning.
Many aspects of growing seedlings require some sort of judgement call--something I do all the time--things vary and there always seems to be a surprize twist or two along the way. By all means, if in doubt, ask!
