Leaves are turning dark purple on two different strains.

can someone tell me why the leaves on my green crack and bubba kush plants are turning a dark purple? is it a nutrient deficiency? or what?

Phosphorus?

This link can be found in the diagnosing plant problems. Check here before everyone yells at you.

http://www.icmag.com/ic/showthread.php?t=11688

k thanks, i'm new to the site.

Those are outdoor plants and this is prob why. Some plants when the temp drop at night with start to turn a purple color, It does look like it could use a little more nitrogen but the flowering season has started and your leaves will start to turn yellow any ways. Nice looking plants, I just found out my last one left was a hermi so I cut her down . Good luck with your grow and welcome to RIU!!

As long as yer feeding her, that seems pretty normal to me.
Look forward to purple buds!

yeah thanks a lot i'll keep that in mind. I just noticed when i switched over to bloom food that's when the color change started happening. And i'm not really to sure about this food.. i think it's for hydroponics but it's all salts and i've been going easy when feeding cuz i don't want to kill my babies. I'm going to start feeding them a little more and if nothing changes then you're probably right, it's just the conditions outside. I know two people who grew the same green crack strain and it started turning purple on them as well, both indoor and out. It could be the strain but my bubba kush is also turning purple.. so that's why i thought it was a nutr def.

thats a nitrogen def