What is causing this?

[Gitane]

Leaves have been turning purple on three different clone strains over the past 10 days, : Girls Scout Cookie, Agent Orange, and White Widow Max. All in soil. Soil PH seems to be 6.5.
The three photos show the progression. New growth still seems to be okay. These have been vegging for 23 days growth has been less previous experience.
My guess is phosphorus deficiency. Yesterday I gave them all a strong dose of Earth Juice Bloom 0-3-1
Thanks to all who view and chime in.

 

[vastok]

Cold ...keep up your evening temps

 

[Gitane]

Thanks, but it's actually the opposite. The plants are outside during the day -lower 70's temp -and at night indoors where the temps are a little higher.

 

[iwltfum]

I think it could be multiple deficiencies or lock out. What were you feeding them before the earth juice bloom? and how what strength were you feeding them at?

 

[Gitane]

They were transplanted from 6 '' pots where they had been vegging as clones for 2 weeks. They then went into the present 1 gallon pots with a complete organic potting soil. They were fed with 1/2 strength earth juice grow, catalyst, micro blast, and meta k one time about a week after they were re-potted. I didn't think I could get a nute lock out with my ph being in the 6 range.

 

[iwltfum]

They were transplanted from 6 '' pots where they had been vegging as clones for 2 weeks. They then went into the present 1 gallon pots with a complete organic potting soil. They were fed with 1/2 strength earth juice grow, catalyst, micro blast, and meta k one time about a week after they were re-potted. I didn't think I could get a nute lock out with my ph being in the 6 range.

I'm not really familiar with soil pH test kits or probes so I just disregarded that piece of information. From what I do know, The probes are a little in accurate. I'm assuming you are affecting the pH of your nutrient solution?

What kind of water are you using?
What is the NPK of the soil?
When do you decided they need water?

 

[Gitane]

Not sure the NPK of the soil but it's a well balanced organic potting soil, like Fox Farms. I use a test kit for the soil (fill a jar 1/2 way with soil, top it off with Ph'd water at 6.5, mix, let it sit for 1/2 hour, then drain the water and test it)
I always ph my tap water to about 6.2-6.6. Regular tap requires a ph down(lemon juice) and with the Earth Juice ph up (sodium bicarbonate).
I water when the tip 2 inches dry out (about every 5 days)

 

[iwltfum]

Not sure the NPK of the soil but it's a well balanced organic potting soil, like Fox Farms. I use a test kit for the soil (fill a jar 1/2 way with soil, top it off with Ph'd water at 6.5, mix, let it sit for 1/2 hour, then drain the water and test it)
I always ph my tap water to about 6.2-6.6. Regular tap requires a ph down(lemon juice) and with the Earth Juice ph up (sodium bicarbonate).
I water when the tip 2 inches dry out (about every 5 days)

Did it start about a week after the first earth juice feeding by any chance?

How hot has it been?
How much light does it get? Direct/Indirect

 

[Gitane]

I think the issue may be the heat. I put plants in the garage at night under CFL's. The last 10 days the garage is about 85 degrees when I bring them in. That 15 degree temp change must be too much for them to handle. I'm not able to keep them under CFLs outside so I'll just keep em outdoors 24/7 now and watch them go into flower, even though they're all pretty scrawny