Lowest fan leaves browning and dying

Got same problem. Started to add nutri and cal mag and for now it stopped

Normally I would say it's one of the major 3 or big four. Although this is not your problem which I will explain it's good to know what the big 4 are that is mobile nutrients. Nitrogen phosphorus potassium are the major top 3 you will see them listed on ever bottled or bag of nutrients with three key numbers N-P-K. The other mobile nutrient is magnesium and it falls in the second tier of nutrients your plants need along with calcium and sulfur. The rest are minor, however you should search the web for a chart that shows each deficiency for all but most importantly the mobile nutrients N P K and magnesium these are taken up by the plant and stored in the lower portion of the leaves or the oldest growth. So if your ph-ing the water correctly it will even take up these nutrients to store them for later. So in the case of nitrogen you will see the bottom leaves are almost always darker green in color and will turn brown if you don't have enough nitrogen. Unfortunately in your case judging by the entire plant itself and more specifically the top new growth being all dark green and beginning to curl up. This means you have to many nutrients. Your plant is honestly to small to really need any nutrients at this point. Especially if you have it in a very nutrient rich soil. So the brown spots, dark green color all over, and curling of the leaves is a definite sign of nutrient burn. My advice search cannabis mobile and in mobile nutrients and their deficiencies on YouTube. Don't just take anyone's advice on YouTube. You should find a real egg head scientist on there who doesn't grow cannabis but is a herbologist

Hi, I wouldn’t worry about those bottoms—- it’s a lack of light and by looks, some water/soil being on them. Just defoliate and you will be fine! Happens to everyone indoors. Good luck ✌️🏻💚🌿

Bottom leaves often get their energy cut off by the plant because they aren't getting enough light for photosynthesis. The plant will sometimes kill them off on their own, but you'd be doing her a favor if you cut them off ahead of time. That said, looking like you have an N toxicity. This can also lead to dark green foliage that eventually begins to die.