Tropicana Cookies Auto FustBuds

From day 32, the plant started flowering. I continue to stretch the branches to promote more even growth. I removed the lower leaves that were not receiving sufficient light. Day 36 - Some leaves have started to yellow and develop spots, while the colas and stems of the lower large leaves are turning purple, indicating a phosphorus deficiency. I flushed the plant with plain water until runoff and measured the PPM output, which registered at 400. This value is significantly low for this stage. I will increase the amount of base nutrients and continue to monitor the plant.