Critical + CBD Auto 1st indoor grow

start of wk7 at day 43, she's continued to stretch but as you can see in the photos, her leaves are not a deep green colour and I think she needs nitrogen. at day 44 she hasn't been watered or fed in a few days as the coco perlite is taking about 5 days to dry out between waterings/feedings. I have included a couple of photos of burn marks on the leaves, if you think you know what it is then let me know. I don't know if they are nutrient burn/spilled nutrient/magnesium deficiency etc. Also, I started some basic lst on her to pull out some of the side branches. day 48 update: ive uploaded 3 more photos. she grew a couple of inches in the last 4 days to 13.5 inches. the spots on the leaves haven't worsened but the older leaves could still be more green. bud sites are developing.