Just noticed some spotting on the older leaves looks like brown spots and yellowing I’m in the last few weeks of flowering is it something going on or getting ready for harvest not sure any advice or explanation to what it could be would be helpful
Looks like a Calcium deficiency.
^This can happen when using filtered water, with low PH (below 6.2 pH, Calcium can get locked out even if the Calcium is physically there)
^It’s recommended to use a Calcium supplement in hydro or coco or soil that hasn’t been supplemented with calcium.
^Also,too much potassium can also sometimes cause the appearance of a calcium deficiency.
^Flush with some calcium supplement and correct the PH amd in about a week it should improve.
Below is some info I used for myself on the above.
https://www.growweedeasy.com/cannabis-plant-problems/calcium-deficiency
Great Luck & Happy Growing 🌱
Are you growing in Coco. If so, could be a magnesium deficiency. Check PH first, if not that then try increasing calmag further. Check PH after calmag as it will likely change your PH.
Anyway, best of luck brother, hope it works out 😉