hi i'm a first grower please help me
my plants must have some kind of nutrient problem as you can see in the photos it's bottom leaves are turning black/brown they are tropical sativas(i think) i keep them in a 12/12 photoperiod, water them with rain water (around 6.5-7.0 ph) and give them a 14-14-14 slow release fertilizer mixed with an 11-23-11 because it looks like they have a phosphorus deficiency but it's not working. any ideas??
