Mg deficient...maybe?

Hi peeps...I have my "box" set up in a shed in my backyard. Temperature control is a bitch. However, now that the summer is starting to close out, at least in my part of the country, temperature control is becoming less of an issue...

This is my second grow. The first crashed when I went on vacation and the aforementioned temperature control, or lack thereof, took its toll on my plants. I have a temperature logger that peaked out at 120 F. Yikes!!!

(as an aside, the temperature logger has been a real asset - easily available on eBay - for those who want to track temperature in their set-ups)

Anyway, I think I have the temperature thing figured out with better ventilation etc, and now I get this...From what I can see on the other posts and threads etc, that I have a Mg2+ deficiency. My goal in this post is that I'm looking for some kind of feel good confirmation...I have 15 plants growing this round. Only three of them show this phenotype.

I'm currently using a soil based grow with Fox Farm Big Bloom and Grow Big according to the FF schedule - feed every 3-4 days.

So is this early Mg2+ deficiency? If so, how do I deal with it...

Thanks

John

mist them with an epsom salt spray 1tbs per gallon make sure its disolves & sprayem down just b4 dark period .or you can water it in the soil .

Run Ca/Mg product! Use the given dose.
pH to 6.5 ALL ingoing liquids.