I think you may be over watering them a little, or over feeding slightly, but dunno how tell you to ck with a soiless mix as I have no experience with that, unless it was DWC, and that's not a problem with DWC...it just sounds like a lot for so young a plant...it doesn't look very serious yet, so make a small adjustment and see how they react.
TANKJR Reviewed by TANKJR on . Does this look like calcium deficiency or maybe boron deficiency? Pics. I noticed these spots on my leaves today, it must have developed in the last 24 hrs. I actually had this same problem on my last grow and it seemed to go away once I started using flowering nutes but I am nowhere near inducing flowering yet. The only thing I have been feeding it is Neptunes Harvest (2-3-1) every second or third watering. The strain is nirvana northern light. Lighting is 1 90 watt led + 2x42 watt cfl for some side lighting. Temperature is usually around 76 degrees. Soil is Rating: 5