Hmmm this one is quite curious, not your usual jam! With some more info we can get you sorted. Is and some more photos of the entire plants would help;
Soil Growers:
1. Are you growing from seed or clones? Clones
2. How old are your plants? 28 Days since put in solo cups
3. How tall are your plants? 11-13 inches
4. What size containers are they planted in? Transplanted from 1 gallon to 5 gallon yesterday
5. What is your soil mix?
Promix HP with added perlite
6. How often do you water and what type of water do you use? Every 2-3 days with RO wated
7. What is the pH of your water? 6.1-6.4
8. What kind of fertilizer do you use and what is its NPK ratio?
Floraflex Veg nutrients
9. Do you foliar feed or spray your plants with anything?
Floraflex Foliar feed,
Grotek Gro-silic and
cal-mag when they were having issues
10. What kind of lights do you use and how many watts combined? (HPS, MH, fluorescent, halogen, incandescent "plant lights") 420w LED quantum board
11. How close are your lights to the plants? 36 inches
12. What size is your grow space in square feet? 16 ft
13. What is the temperature and humidity in your grow space? 26-27.5c and 60-68 rh
14. What is the pH of the soil? Unsure as i just transplanted and have not got runoff
15. Have you noticed any insect activity in your grow space? None
16. How much experience do you have growing? Second grow