Leaves Curling up, but still green as fuck...?

So between last night and this morning my plants had a record growth spurt of about 3-4 inches in height, and 4 inches in width almost too. The only problem is, now on two of my plants the leaves are curling upwards. I immediately thought Mg deficiency, but the leaves are still GREEEEEEEN, so i held off on the epsoms. Another possibility that came to mind is heat stress, but all the plants would have heat stress because theyre being grown under the same light, and are all the same height from the bulb. ANOTHER theory is that it could be wind stress, as i had a fan blowing on my leaves all night long on medium which is pretty gnarly n blows the leaves around pretty bad.

I know im getting closer to the problem, but i need some expert advice. Anybody ever have this happen before?? could it just be a result of the growth spurt, that its a sign of a REALLY healthy plant that just grew a bunch??? any help here would be much appreciated guys.

-thanks

-K1

K, how dry did it get in grow last night?

i have constant 30% humidity with temp highs around 82 and lows around 76. things were just like they were usually at night. i did move the lights a little bit closer to the plants though - i wanted to make sure that during their spurt they didnt stretch too much because of space restrictions. I succeeded in keepin them short, but now a couple leaves on a couple plants look like green ganja taco shells, lol.

Im having the same problem with my lowryders but its only the first set up leaves from the bottom

Are the edges curling up and inward? This IME is more than likely due to low humidity coupled with slightly elevated temps, and/or slight overfertilization. The leaves bend trying to transpirate and they pull more nute rich water from the medium complicatingthe problem. Remember, even slightly higher temps hold much more water in the air, thereby pulling more water from the medium through the leaves.

yeah, i know what your saying, but its not over ferting. Ive done two feedings where ive used my FF regimen since seedling. The grow is 3 na half weeks old. I did my first fert at 2 na half weeks, then water, then fert, then water, n then ill be ferting again tomorrow. Its more than likely an Mg deficiency, cuz i sprayed it with some distilled n epsoms and the leaves started calming back down n straightening out.

But i dont get it though -- why would they be deficient in Mg already??? im feeding them according to schedule, and the soil i used was brand new - i dont reuse soil unless i HAVE TO (FF ocean forest). So what then? do i just hit them with a small ass dose of cal/mag whenever i fert them tomorrow? i wanna fix the problem, but i also dont wanna fuckin overfert forreal, and end up with some shitty lookin plants. Of course im not worried that im gonna kill them, ive had enough experience with my past grow that i can save their lives if ever in a jam that big, but Im still a novice when it comes to dosing the plants with nutrients.