seedling new growth slightly pale green. Nitrogen excess or deficiency?

A smaller volume of soil depletes faster, than a larger one does. That's why as the plant gets bigger, it's harder to keep up. Look to nature. Outdoor plants are using as much soil as possible. Both by roots, and mycorrhizae, but like I said, a smaller volume isn't impossible, just more work, and you have to have good timing, good watering practices, and good knowledge of what your plants are telling you what they want.

I finally cut down my first grow so it is nice to have some room in my grow room. I also just ordered some seeds to do microgreens to utilize the spare space of the grow room. I definitely eat more than I smoke.
I just took a few pictures of the plants to give everyone a follow-up