I currently have brown/burnt leaf tips and the 3 plants are in their 5th week of veg. I have yet to add any nutrients to these plants (I'm waiting until they start 12/12 to add any). From what I've read, the plants seem to fit the description of nute burn but how is that possible if I haven't added any yet. They were potted in Pro-Max soil mixed w/ earthworm castings at a 2 to 1 soil to worm ratio. Pics attached.