Quick check: Should I be worried about my Lemon Drops?

Since I moved my Lemon Drops to a different floor of the house some weeks ago they've been looking more and more shaky. They're all 24+" and still growing at a steady pace. They all have plenty of buds (none dropped and none flowering yet), but some weeks ago they started getting these burnt leaves that started out as just black stuff around the edged of some leaves, but now look more sickly:



Lately I'm also seeing some dropped leaves and some yellow ones:



I thought yellow leaves usually indicated N deficiency, but I have a hard time believing that here. Could it be iron? The fertilizer they got does contain iron though...
Today I noticed one of the larger leaves looking bad in a slightly different way:




One or two of these plants need a larger pot, but the others have plenty of room to grow and they all show the same symptoms. I've only fertilized them twice with NPK 5,6-2,0-7,1, but I stopped that and cut back on the water (weeks ago) when they started to look burnt.

The newer growth looks healthy enough to me:

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And the red Hab and Early Jalapeños they're hanging around with have none of those issues.
Is this something I should be doing something about or do I just need to give them time since the newer growth looks fine?




All the pictures are clickable thumbnails.

Edge burn on the leaves is usually an indication of fertilizer burn. Just a little bit to much dose or too often. Love the Lemon Drops! I don't think moving to a different room in the house is an issue as long as there is light or window.

Good Luck Mike If the new growth is fine then you are probably ok, just watch it for awhile.

Seems to be getting worse faster now. Weeks since I gave that second dose of fertilizer.

New discolored leaves:

This one and a few others are getting these small holes in them:

Overall the plants are looking like this:


Doesn't this have to be something else than a bit of fert burn?

Try flushing them out with 3 times more 1/4 strength nute solution than the volume of your soil, and see what that does. If it's nute burn you will know within a few days, as everything gets back to normal, if it's something else, youll know because, well...you know.