K deficiency or nute burn? And some small holes in leaves.

Hey, buddy! 👋 It's a phosphorus deficiency, no doubt about it! The stems of the leaves are red - that's a sign of phosphorus shortage in the tissues! The foliage is unevenly green - problems with nutrient absorption, possibly due to high nitrogen content in the fertilizers, or maybe from calcium overdose. I assume you're not adding fertilizers with "Bloom" in the name to your watering. It's time to start doing that, my friend! The ratio of Grow to Bloom additives in the middle of the vegetative stage should be (1:1). You should have introduced the plant to the Bloom additive as soon as you had the first 5 pairs of leaves! 👌 Good luck, buddy! ✊😇