What is going on? Any help appreciated. Super soil, 5 gal fab pots, 79°, 50% RH, last 2 feedings only pH water of 6.2-6.8. 4 P1500 Vipar LEDs. Other 4 plants are fine.
When growing in super soil you still need to amend with nutrients every 3 weeks or so. If you haven't given them anything other than what was initially in the soil, then the problem is that they need food. Those plants are definitely not getting enough nitrogen. Check soil ph first, you want 6.5-6.8 in soil, if thats good then you need to top dress with an organic nutrient. A shot of recharge wouldn't hurt either. Happy growing.
You should really keep a diary to help people help you. Possibly nutrient lockout but it’s hard to tell without all the info, you watering with at least 20% runoff?