I did see your post earlier and there doing beautiful! going to be monsters through flower.. I'm having the exact same problem mine are in pre flower at the minute. don't get me wrong yours are alot bigger than mine but I'm UK lol, Im thinking it's either down to an under watering problem as I had this early on watered a bit more on each water and it sorted her out but I doubt that as all the leaves would be turning eventually a month in.. or it's down to there just the lower leaves dying off due to not getting enough sources needed as the rest plant is doing amazing. 3rd option it's down to N. I'm having the exact same problem and that's just my opinion.
I’m having the same issue, I believe I locked out the magnesium on my plants with a high ph.” (Used straight water from tap while In a hurry) yours does like a magnesium issue to me more than nitrogen IMO. Often it’ll get locked out from low ph, or lack of cal mag / Epsom salts, high ph and/or lockout from too many nutrients. I know it’s a pain in the ass bit Perhaps a good flush at 7.0 ph and then once dries a bit start with mild nutrient solution containing all relevant nutrients for the growing phase you are in, and proper ph for your medium. This should rule out all of the above.
