Curling of older leaves

Hi there Geo , long time growmie ! Here you have a pretty serious root zone issue , basically it's really bad "water mold" on the roots. So you need to fix the problem roots , this you can do by using additives like beneficial bacteria which take longer to fix the problem, or humic or fluvic acid or even H2O2 dilluted to a 0.3% during your watering. using a combo of humic acid and beneficial bacteria is the best way for you. If you start to add humic acid the problem will stop spreading and the plant will fully recover in 10 days to two weeks . Hope this helps ! 🚀

Hello my friend i have experimented this situation with my sativas essentially. It is called eagle talon and it is due to EC which is to high in your soil or it is due to overwatering. Peace

Nitrogen toxicty you need to flush her and flush her pretty quick my friend the medium looks dry enough so just some ph balanced water for your next feed let it dry out and then re evaluate hopefully you wont get a nutrient lock out but be prepaired for her to finish alot past her time line as she will have been stunted :) Id add about 3 more weeks to the ending and that should be about right if you get her sorted anyway. Erm some really large internode spacing here do you hang your light 40cm from the canopy ? if using led then i would advise that if your using hps I advise you get a Metal Halide bulb to use for veg that specturum is almost perfect for veg and that would sort your internode spacing out to less than an inch :) Best of luck anyway my friend ever need anymore help just hit up my dm always happy to help :)