Phosphorus def. or from the cold?

I have been having several nights in the 40's, and stems turning purple I know and have, but I'm not sure if the leaves are turning also, or it's from lack of P.
It is happening to the older fan leaves worse, and starting on some of the smaller fan leaves.
I only have a couple weeks left, so at this point I'm just curious......... I think it will make it until hack time.
I also noticed that the discoloration seems darker in the morning hours, but seems to get lighter in the afternoon/ evening.

Any opinions what this is?

P def. DUE to the cold.

I have a hunch, not a real opinion ... that it's just temps. However info (what strain? how close to done? what kind of nutrition? Maybe a whole-plant pic?) might help someone with more experience than mine pipe up. Just a thought. cn

Is the new growth yellow or yellowing?

cold, boggy, or alkaline conditions can lock up P

OK, here goes........ CN,- Bagseed, and I'm hoping it's only a couple weeks from the chopping block.
I have started bringing them in at night when I get down below 50, since I noticed with just a cold night here and there, she seemed to have growth spurts, but last week I had 6 consecutive nights of 40 degree weather, and that's when the discoloration started, and growth slowed quite a bit.
On this plant, I am using some 0-15-11 and 1 tsp molasses every other water.
On my Sativa dom. plant, I have been using the same, but occasionally adding some MG all purpose for N since that one is getting really light green all over. It really never got large fan leaves, just a bunch of small ones.

HotShot,-I haven't had much new growth on this one, aside from a couple new buds starting low down on the main stalk where I had previously lollipopped, but what leaves haven't turned the brownish/purple color are still a decent green.

scroglodyte said:

cold, boggy, or alkaline conditions can lock up P

Click to expand...

Then that is what happened.
Thanks Scrog.
Do you think I should continue regular feeding schedule? Or wait a bit and let it take up what is already in the soil now that I have started bringing it in at night?

I would for sure point more at the temps before adding anything just because its the first thing that you know without a dout is off. 40degrees is just to cold.