The 2nd and 4th in the row of pictures could be spider mites or thrips. I thought I was feeding too much nitrogen because tips looked burnt, but not nearly that bad.
I had both, and had to check a few leaves from bad area, under a usb microscope close up. If the you can see some color in a mite with like 4 hairs pointed forward, probably spider mite. I forget what thrips looked like, but they will breed in the soil or coco.
I the are white or almost transparent they would be broad mites. They do not cause burnt looking leaves. They cause twisted growth of top leaves, and almost all growth stops.
Now for having too much nitrogen in your growing mediums or soil. The plant will have like an overall DARK green look and have delayed maturity. Due to Nitrogen being involved in vegetative growth, to much nitrogen will result in tall plants with weak stems. New growth will be very lively and plant transpiration will be high, but not always. Nitrogen toxicity can be seen when there are very very dry conditions almost as if there was a drought, which may show a burning effect. If you give your plants ammonium based nutrients they may show NH4+ toxicity, which will show a smaller plant growth and lesions that occur on stems and roots, leaf margins that will roll downward. Also the big fan leaves will have “the claw” look. The tips will point down but the leaves will stay up as if when you bend your fingers downwards. Leaves can be twisted when growing… mainly new growths. Roots will be under developed along with the slowing of flowering. Yields will be decreased, because to much nitrogen in early stages of flowering slows down bud growth. Water uptake is slowing down from the vascular breakdown of the plants as well. Too much potassium and nitrogen will lock out calcium as well.
