Definitely get a reading on your pH when you can, which is something that's important to know, but it almost looks like you may have had a fluorescent tube resting on those particular leaves, judging from the semi-straight line on surrounding foliage. If it continues to spread to other leaves, you can rule this out, but if you don't see any signs of progression, then you may have just burned the leaves there the fluoros were accidentally touching them. You can do a flush, but at 4 weeks, it's not always necessary. If you haven't been using your nutrients but for a short time, you probably don't need to flush. If you do, make sure to follow it up by feeding with a complete fertilizer at 1/4 strength. (You know the drill! :jointsmile
Mr. Clandestine Reviewed by Mr. Clandestine on . phosphorus def..or not??PLEASE HELP Hi All 2 days ago I transplanted my girls. They were in a tight place where I couldn't see them very well when they went into the bigger pots, but I think I would of noticed this. They were moved to a bigger area today and this is what I saw. age: about 4wks soil: vortex lady bug 2/3 & 1/3 perlite feed: fox farm grow big, 1tsp/gal & foiler spray liquid karma every other feed. lights: all fluros..as close as I can get without burning I have done the research and it looks like phosphorus Rating: 5