I have read much about the need to start with plants that don't have high nutrient requirements until the system matures, but I haven't seen anything on whether high nitrates cause problems for plants. As I have been reworking my system to account for temp, humidity and indoor lighting requirements, I have been running without plants (only duckweed) for a couple of weeks. Also, the nitrates in my system have been >100ppm since soon after introducing the fish and have not come down since.

I expect to add a bunch of greens shortly, but these have been recently sown, and I wonder whether placing them in water with very high nitrates will cause damage/stunted growth. Will the leaves become too succulant and thus more prone to disease? Should I do a major water change just prior to adding plants?

I have had decent success with growing outdoors in soil, but AP growing in my garage has thus far eluded me. Fish are fine, but plants have underperformed, and I wanted to avoid another round of dissapointments.