Nitrogen deficiency or magnesium burn?

I have 6 plants on my indoor trellis, and this one is showing some troubling symptoms in the leaves. I transplanted all 6 plants a few weeks ago into these 5 gallon grow bags. Due to financial constraints, I bought some organic potting soil and amended it instead of making it from scratch like I usually do. I can’t remember the brand but it’s the blue and yellow bag from Home Depot. Says it’s full of kelp and guano and shit.

Anyway I haven’t fed the plants since I repotted them because I figured that soil is pretty hot. The only nutrients I added to it was some bone meal and compost, but I cut it with peat moss, perlite, and vermiculite as well.

So I have no idea what’s causing this or how to mitigate it, but it looks like magnesium burn. Do I wait it out, or should I add a little bit of nitrogen to see if I get an improvement? I also have some flushing solution but since it contains magnesium I’m hesitant to use it. I was seriously planning on flipping these tomorrow once my grow tent arrives and I can completely isolate the other veg lights, but I don’t know...

I’ve had these vegging under my flower lights for about 2 months ever since I needed to make room in my veg space for their clones.

This is the only plant that’s showing any kind of symptoms. It’s a nirvana aurora indica. The other phenos aren’t having these issues and neither is the white widow on the other side of the canopy. I’m not sure if this should be in the organic growing or indoor growing forum but since I think it’s an organic nutrient issue I’ll post it here.

Not trying to gratuitously bump my thread, but it looks like I was reading the site I referred to wrong and it looks like it could actually be a magnesium deficiency. Should I just use epsom salt?

Definitely not nitrogen, that would start at the bottom of the plant.

I am gonna say you need more phosphorous.

I decided to flush the soil and give them a light dose of nitrogen, phosphorus, and magnesium. I think it is definitely a deficiency.

All the flushing just makes things worse. Try and feed a little stronger than light.

I agree. I only flushed one plant and that was back when I was under the wrong impression that it was an excess and not a deficiency. Today I mixed up 2 gallons of a “complete” plant food with fish emulsion, guano tea, epsom salt, and unsulfured blackstrap molasses and applied it to all 6 plants, as well as giving them a very dilute epsom salt foliar spray. I hope it isn’t too much too fast. I really want to get flowering underway for these plants but I don’t want to flip them while they’re hungry. I really think it’s a magnesium deficiency since that can screw with uptake of all the other nutes.

Would it be okay to go ahead and switch them to 12/12, or should I wait until the leaves look good? I don’t want them to start stretching and then get nutrient lockout.