Hello, I am 15 days into my grow and after a long nights sleep I checked up on my plant and noticed a small yellow spot on one of the old leaves. Yesterday I noticed a slightly different color in the the same area the spot had developed. I am growing in miracle grow potting mix (I know its not great, had to do for now ). The strain is bagseed, dealer said it was "cali green", an og kush hybrid. They are under a 250W 8U 2700k CFL(using it throughout veg and flower). They hang about 6 inches above the plant, I moved them up about 4 days ago to allow some height growth. For the past week I have been watering it whenever dry, but I haven't been saturating it. However, yesterday, my soil's pH was lower than 6 (5.5-5.8) so I flushed it and watered it with the corrected pH (6.5-6.8, which it is currently at). I don't have a thermometer in the box but my house has a room temperature of 72 at all times, and judging from the feeling inside I would say it is around 80, it's a bit warmer but being closed up for 12 hours it doesn't get hot so I assume the airflow is fine. I am using a 2 gallon pot. There are two 120mm fans blowing on the plant (not too much but at all times) I am guessing that the pH was the problem? Any help is appreciated
I don't think it's anything to worry about but it does sound like you did everything right. If it was nutritionally based then it was probably a low pH locking out some magnesium or calcium. Likely Mg though. You're good. Those leaves don't even matter in the long run. I have them removed by the 4th week because they wind up so far from the light source. Helps with the air circulation too.