Serrated edges/cupping help

Went to check on my plants and noticed all of my plants today are starting some cupping/ serrated edging on the leaves. even on new growth.

is this heat stress? nutrient over load?

1. bag seed
2. at 15days from seed
3. Soil setup - seedling in MG Potting mix ( i know bad ) Then after day 6 transplanted to MG Organic which is soil/coco mixture along with some perlite.
4. Watered only no nutes. ( did hav a problem with our well water coming out 8.2ph so i switched to RO/dist water for last feeding they had )
5. Soil ph - 6.8
6. CFL Grow 8 - 5000k 2 - 2700 . Light is about 2-3 inches above plants with a fan circulating the bulbs. i put my hand in between with no problems.

A few days ago it was like 1 leaf that had this cupping but now a bunch are getting it. i also have a few copper spots showing on some leaves as well that happened last week. hasnt really persisted but i have noticed 1 or 2 new ones. Reading uncle bens stress thread it sounds like i have overfeeding problem but i havnt fed anything.

This showing heat stress? needing N now maybe? im getting slight light coloring between the veins as well. light green/yellow. deff not overwatering as they havnt been watered in a few days and should need it by about midnite tonite.

Pics below


2 different plants pictured.

Any help would be great!

Yellowing between the veins is magnesium, orange spots is calcium/lock out cupping is usually over feeding, which shows on new growth first.

My guess is miracle grow is meant for veggies bought at lowes or Home Depot which are probably older cuttings/clones which are a little starved after baking in the sun without being fed for who knows how long. So someone takes them home and pots them up and puts them somewhere on a porch where they can get some shade and be watered enough. Then they react nicely.

That being said mg soil might be a little hot for your 2 week old plants. I would say for sure if they reacted that way under HID lights not completely sure with them being under cfls.

If you can hold your hand under your lights no problem then most likely not heat related

TThanks for the reply gu420.

after reading i did lean towards mag/cal problems. I figured maybe that bit of MG I used has been burning them a bit.

iim thinking the bad pH water caused my lockup of cal/mg. Will see how they act the next few days with this new water.

i was hoping the solo cup worth of mg wasn't going to hurt it to much so we'll see how they act.

jjust not sure if its wanting any actual feeding yet but ill wait it out.

i have some botanicare coming soon.

AAny more responses are greatly appreciated. All more knowledge for me and others!