Why?

Why is it like this

Probably should change up lighting, temp, humidity, grow medium, watering schedule, ph and feed strength.

whats the strain? seems like a very sativa morphology aggrevated by temps and lights probably also with sativa doms you can go as low as 8-10hrs on/ 16-14hrs off especially in the second half of the flowering period

Heat and light.

Too much light? Top temp is maybe 70