Please help with brown spots and leaves that curls upwards

Hi mate. looks like a calmag deficiency. when using led or coco , they both can leech the mag from the nutrients unfortunately. We can supplement with a good calmag product . if allowed to continue , they will be denied vital my and be held back. the leaves will get more spots and eventually die off. dont worry though as it is an easy solution. keep ph 5.8 for coco and feed daily to run off. if in soil then a slightly higher pH of 6.0 -6.2 is OK as the soil will buffer slightly. Remember autos often don't feed heavy too. A great strain choice and I loved my big lady of this one. beautiful smoke too. Good luck buddy

Here is a link to compare images and common traits for PK deficiencies! https://growingexposed.com/cannabis-doctor/phosphorus-deficiency/

This appears to be a phosphorus deficiency, potentially caused by nutrient lockout or not enough PK! I would check the ph of your runoff, it should be about .5-.8 lower than the water going in. I would also check the EC of your soil as well to see what kind of readings you get. Without knowing the runoff ph and EC it’s extremely hard to tell if you’re over feeding. But over feeding typically leads to burnt tips and leaves, not so much brown splotches!