First time grower here and I've been searching and searching but I can't seem to figure out why my plants are getting these spots and stains. At first I thought it was a Nute issue because I had some burnt tips, but I have been barely feeding nutes and it keeps coming. I've clipped leaves with the spots but everyday I find new spots. The spots do not rub off and have a yellowish color. I don't think it's rust but honestly, I'm not sure. I have good circulation and I PH my water between 6.2-6.5. I have 5 plants, all different strains. I feed 1/4-1/2 teaspoon of GH Flora Trio and CalMagic, which is well below the recommended feeding chart recommendation. I'm growing in Black and Gold organic soil with 15-25% perlite. All plants are in veg, oldest being 70 days in and the smallest being 36 days in. I see the spots on 3-4 of the plants, however my tall sativa plant seems to get it the worst. Any help would be highly appreciated . You guys are the best, thanks alot!!
Side note, I realized 2 of my plants are heavier than others. I kinda feel the soil to be a little "hard", is that normal? Is it not drinking? They're in 3 gallon pots, indoor grow, 600w Full Spectrum.
6.2-6.5? Isn't that like..a little high? Far as I know anyway...but that's very little. Can you show us the underside of the leaf? I take it you've inspected this yourself...some bugs/mites can chomp tiny holes and suck the good stuff outta leaves? That said I'm not 100% on what nutrient burns would look like either... As for your "heavier" ones. What's it growing in? Do you have anything in place to assist drainage/root space? Like perlite in the mix, or maybe some clay balls down the bottom of the pots etc? When you water, do the "heavy" ones drip/drain as much as the others? I guess depending on the size/age of the plants they may have ended up with some clumps of dry medium (though this would be the light ones) that isn't like absorbing as much water as it should? Or, your heavy ones....might not be draining properly... Is it at the point you could like, consider re-potting them? That would give you an inside look at what's right/wrong with either of them.
I can't tell you what that is but I would suggest buying a little soil test kit. It will give you a good idea of your N-P-K levels. You may want to pick up a few if you aren't sure that all the plants have the same issue going on, or find one that can do multiple tests. I just did this with my first grow because I was having leaves turning yellow (not in the same way as yours), added the needed amendments, and now my plants are happy looking and a nice deep green again. I think the test kit was like $6. Are you spraying your nutes on the leaves? That could be whats causing the yellow spotting in the middle of the leaf.