Curling leaves concern at F50

Defintely at the point where you scope the trichomes daily. I wouldn't do anything too drastic in the last week or few days as far as reacting to any issues. it could be nute-related, as you have some symptoms. could be the light like you suspect - such symptoms can take a long time to manifest from the point at which too much light is given. it's not always a quick path from cause to effect. could be senescence - the plant is simply dying as it nears harvest and beyond. (barring a re-vege). Watering -- 1. Water entire pot, always. never half-ass it. don't try to choose the volume of water because you like the roundness of that number 2. Wait for top 1" to dry 3. Repeat FFOF has a high water per volume capacity. It stays wet for a long time. You should add perlite or similar to up the drainage amendments to roughly 50% of total volume in future. This will cause more frequent irrigation but will be better for root development and make it virtually impossible to drown the roots. The amount of water it takes to re-saturate is dependent on how long you wait between (of course) but more importantly how it is constituted. So, how much you need to give will be different than someone else unless they do the exact same medium with same drainage properties etc etc. A little runoff is fine. If you consistenty re-irrigate at same loss of weight / same dryback up top, then it will take the same volume each time. You learn this volume of water in hindsight, and not a number you choose off the top of your head or what 'feels' right. Let tangible facts dictate how much you need. You can learn to reduce waste (runoff). If you overfeed, you can give extra runoff to dilute EC of substrate. If properly constituted with enough drainage amendments (like perlite), then you have no concern for overwatering in any common sense context - impossible to overwater and shouldn't even be a concern or thought in your head. Watering is simple. Don't complicate it. The act of watering should never be a cause of any problem if you follow those 3 simple steps and constitute your medium properly. FFOF needs more drainage amendments one way or another... leca balls, perlite, vermiculite, etc... i'd recommend Verm#3 or perlite #2 as it is a good size that also won't physically impede roots.