I think that some of you are missing a key in lower temps!
It's not just the plant above ground but, the root system is just as, if not more important to get that day/night temp swing...
Inside while trying for lower temps in rooms. I quickly noticed that outdoor plants colored faster and could get very rich and varying in color expression.
Inside plants when supplemented with K2SO4. Colored a bit quicker but, still did not keep up with outdoor.
It is also noted that indoors expressed color (actual coloring and not yellowing) in late bloom. More so the later you run....
So, the cooling of the soil containing the root ball. Is a major player in coloring naturally in bloom. I say this for simple reasons.
In nature, the air cools quickly and begins acting on the plants. As time goes by the soil also begins to cool and that helps play into the coloring effect. Now the sun comes up, warms the plant fast but the soil slower. This means cooler soil and root conditions as the soil warms slower. The roots are now not just reaching a 10-15 deg F but in a sense. holding that for the same amount of time as the air. Thing is it takes longer to cool and longer to warm. Not just getting an equalibrium in time but an offset in time relative to each at the same points.
It will be less change over all in the soil. And as the season progress's. You get cooler plant to air contact over soil/root but, that too will progress to cooler..
Light can be important. Intensity levels need to be there.
I am not of the belief that cannabis coloring is greatly effected by root zone pH.....It's a plant family thing....
Bottom line....Those pot soil temps are just as, if not more important then air temps. In my observation.
