All leaves starting to die week 8 of flower

The plant was looking for some potassium (some while ago by the look of it) and couldn't find it so took it from the leaves or she couldn't access it because of the incorrect ph range or overabundance of another nutrient. This is often caused by ph fluctuations or nute buildup. Although it's a bit late now Flush her out

Light/heat stress

You should consider adding additional nutrients. You will need calcium & magnesium and other micro nutes/supplements to deliver everything they want. I'm learning still into my 4th session and it's clear that nutrients if delivered properly will definitely enhance your grow. However, all the best nutrients, lighting and conditions will never make the best bud if the seed quality is under par. It could also be pheno type related to where 1 seed is fantastic and one seed sucks no matter who you are. major reason for cloning as you can skip this crap Everytime. I have noticed that auto flowers can have small trichomes and less of them, sometimes. I have grown a few that were good but only 1 that was great. Buy name brand breeder seeds only. Don't waste your time anywhere else. Cannabis cup winners and just highly recommend breeders. I think you have a small combination of things causing this. 1 also being nutrient lock out to early from salt build up. Trying flushing in between feeding with nutes. Nutes 1 day then next day they need re wet do water only, do water only a few times in between each feed but when you do the water only feeds make sure it rinsed the soil from the oil nutrients. Technically, when watering with nutes the same applies, water it until it runs out the bottom a decent amount. This pushes old out as new comes in. I'm really really starting to learn this exact step because it will make your leaves die earlier, drying them out and making some almost crispy. From what iv started to notice, rinsing my pots more often to flush the soil out this most recent run (no diary to show exactly) literally made a big difference for me. Good luck I hope you can narrow down for the future. Stick with name brand breeder, that's step 1. Then step 2 incorporate a few extra nutrient supplements. Silica is very good to have to for health of the plant. Look into it. Also essential oil builders like Humboldt sweet & sticky. Deliver extra pk with Kool bloom or something with high strength phosphorus & potassium but don't exclude some nitrogen. It needs it still just much lass then in grow. Mixing a small amount of grow nutes to your bloom nutes could also help organize your npk ratio. Just be careful using nutrients in excess. When you mix several use then of each to counter. As each bottle says, amounts are when used as a stand alone, meaning with nothing else mixed, which almost never happens. Research feed charts and salt build up, how to water with run off. Etc. Hang in there your will get this better each round.

Hey, not sure but could be a nutrient deficiency, anyway in week 8 you are close to harvest, so provide only water to be sure you flush, enjoy !

Hi. I'm not used to your nutes but I think you may have needed something else with it in flower. I wouldn't worry to much now as the plant is also naturally fading away because its close to being ripe for harvest. Good luck.