So this Thunder Cookies #2 is on day 19 from seed and just noticed that the first set of one pointed leafs had this on them. None of the other leafs are affected. Just the first 2 leafs.
Please copy and paste and fill this ticket out as best you can
Strain; Type, Bag seed, or NA:
Age from sprout:
Age from flower:
Soil in pots, Hydroponic, or Coco?
How often do I water and how do I determine when to water:
PH of runoff or solution in reservoir?
What is strength of nutrient mix? EC, or TDS.
Indoor or Outdoor:
Room size:
Light system, size, height from plants:
Temps; Day, Night:
Humidity; Day, Night:
Ventilation system; Yes, No, Size:
AC, Humidifier, De-humidifier:
Co2; Yes, No:
Any other info you think is pertinent:
Age from sprout: 19 Days as of 2/8
Age from flower: n/a
Soil in pots, Hydroponic, or Coco?: soil medium. FFOF.
How often do I water and how do I determine when to water: as of now it’s about every other day. I decide to water when the first inch or so is dry.
PH of runoff or solution in reservoir? Haven’t tested yet.
What is strength of nutrient mix? EC, or TDS. Not using any. Distilled water phed to 6.5
Indoor or Outdoor: indoor
Room size: 1.5 by 6 ft. Lol homemade tub box thing. Grow tent will be here Monday though 
Light system, size, height from plants: 600w YGrow. It is 2ft from the canopy.
Temps; Day, Night: day-low 80s. Night is 70s.
Humidity; Day, Night: my low is 22% and my high is 55%.
Ventilation system; Yes, No, Size: a fan lol. Box doesn’t have a door. Just a curtain I leave slightly cracked for ventilation.
AC, Humidifier, De-humidifier: n/a
Co2; Yes, No: n/a
Any other info you think is pertinent: n/a
Are the affected leaves closest to your soil? Possible soil splashed onto them during watering?
Well yes it’s close to the soil but I know it hasn’t splashed.
Your plants look good, maybe a tiny bit of nute burn from the FFOF.
The FFOF soil is a hot soil, and younger plants be be susceptible to nute burn as a result. Keep doing what you are doing, don’t add any nutes. Make sure that the pH is 6.5.
If you are using distilled water. You are eventually going to need calmag.
When you water, water to runoff, and measure the pH and the ppms of the water you collect. About 10% of what you put in should come out the bottom.
You need to transplant soon. What size pots are they now and what do you have available to upgrade to?
I would take a close look for bugs too.
