Bottom leaves yellowing at beginning of flower

Chek Ph.

Some of the issue is caused by the leaves touching the moist substrate. Cut off the worst affected ones, which will increase air flow too. Some of the yellowing is caused by those older leaves now being in shade and not receiving enough direct light, which causes the yellowing. I would also be feeding half grow and half bloom for another week or two before switching to straight bloom nutrients, cannabis still needs adequate nitrogen in early flower. This early yellowing is quite common it seems with people who switch to bloom nutrients as soon as they see the first pistils appearing. Flowering doesn't really commence in earnest until 3 weeks or so after the first pistils appear, so I generally continue with grow nutrients for those first weeks and don't seem to ever suffer with plants that go yellow too early. Hope his helps, Organoman.

I kind of feel it’s starting a lockout of cal mg. Try flushing plain water for 48 hours and then reduce your ec of your nutrients

Does your thermometer read 27C and 82% humidity? That might be a bit hot if that’s the consistent temperature. She also looks quite dry? How much are you watering and how often? My plants had a similar problem and I was under watering. The plants then had the same issue with the lower leaves and got nute burn because they were too thirsty. Try a good water until run off of plain PH balanced water and see if she picks up. Cut off the yellowing leaves and see how you go.

Honestly matey I think it’s early signs of nitrogen deficiency. Try adjusting your nutrients , and check PH. Good luck with you grow bro 💪

If the leaves have been touching the grow medium then that's most likely the problem. Remove those leaves and watch the others. If the other leaves start showing signs it could be a ph problem or you need to increase your bloom feed.