New at growing, hope someone can help

I tried to look online to see what nutrients my plant might need or any other reason why but I have no idea what it maybe. I live in Michigan, my plant sits by my window (6 inches away from) I have a heater set at 80'. I have a fan for circulation. I have a timer set so it gets 18 hours of light from 8am to 2am. my plant is about 2 1/2 feet tall. Over the last few day it started looking like this (pictures below), I have no idea if this is normal or not. Online I seen it looks like a potassium problem, so I just gave it wood ashes but have no idea if that is the solution. If anyone has any ideas, I would greatly appreciate it.

so up until the wood ashes, you haven't given it a any nutrients at all?

You have it by the window AND you give it 18 hours of light....?

Looks to be all around hungry showing N, K and Mg deficiencies most. Hope you didnt use to many wood ashes. They are not really a good choice to use in container grows.

#1: What soil?
#2: What are you feeding it and how often?

This plant needs a good feeding. Keep your bitchs skinny and plants fat.

what do you think would be the best levels 10 5 10 ?

Yes I have a timer so when the light gets on at 5pm and off at 2am

Ya she's just hungry man!