Any idea what causes this

5 weeks into flower with strawberry cough and Girl Scout cookies. Temp 18-23 ph 6.5 2 liters of water in 3 g fabrics pots every two days seems to dry quick notes is gh trio half strength every second watering with thier root booster, floralicious plus,kool bloom 450 w led 24 hr ventilation and fan on canopy. Seems every couple days like ten or so bottom leaves suddenly yellow brown curl up and fall off regardless if I’ve watered or fertilized everything up top seems great lots of red stems but I think that’s the strains

Could possibly be just a lack of light penetration to the bottom causing the old growth to die off due to insufficient light.


I wouldnt worry unless it starts spreading.