Leaves droopy / Yellowing leaves, Help appreciated

[Gingz]

Something is wrong w/one of my plants. Its' leaves never perked up after watering on 9/21. The plant's growth has slowed & a leave has shown signs of yellowing. I checked the soil w/my index finger knuckle & it was dry so I watered again today, 9/24.

The plant is 6 weeks from sprout, Chemdog by Claybourne CO.

Grown in 3G fabrix pots indoors, 3' x 3' x 6'

Soil is Fox Farm Ocean Forest

Lights are Spider Farmer SF2000 (@40%) & Viparspectra tc600 (VEG75% / 0%BLOOM), both 24in above canopy

Temps this week have avg. 82F w/High of 93.2 & Low of 67.8F

RH has averaged 58%

The plants haven't received any nutrients, just filtered tap water pH'ed to 6.4-6.6 @ an avg PPM of 135

I took a pH/EC reading of the runoff today. The problem plant was 6.29 pH @ 235 PPM.

I'm leaning towards Nitrogen Deficiency but not sure. Any thoughts or opinions would be greatly appreciated.

 

[Beachwalker]

Overwatered, that check with your knuckle thing is wrong, you want the whole of the soil to dry out before you water it again, search 'wet/dry watering cycle'

 

[Gingz]

Could be overwatered, how often do you water?

I water every 3 to 4 days, around 1/3 gallon per plant. I test by wiggling my index finger through the top soil to the second knuckle, as well as lift the pots. Soil felt dry & pots light. All the pictures in the post were taken Just after it was watered So it’s more droopy than it was before.