older leaves are turning yellow and dying

I figure this is just the budsites using the energy from the fan leaves its been flowering for 2 weeks. 4ft. tall, 4-28-6 fert, 10 hours of direct sunlight. thanks for any comments or suggestions. all 3 pics are same plant. plant appears to be healthy. I put this plant out around june 26 it was 8 inches tall.

Yea once they start flowering the leaves at the bottom die its normal