Notes on Nitrogen Deficiency in Plants:
Nitrogen is a macronutrient.
Symptoms: Older leaves will yellow, especially at the bottom of the plant. Stems might be yellow and spindly. Growth is slower and foliage might be light green. Sources: More fish! Urea. Notes: In an established system with fish that match your grow area, this should not be a problem. Fish waste is turned into ammonia, which turns into nitrites, then nitrates. A brand new system doesn’t have the nitrifying bacteria built up yet, but after 6-10 weeks water with urea/ammonia in it will naturally form the bacteria needed to create nitrates. Danger: Nitrogens are toxic to fish in higher levels. Your test kit will tell you how many PPM you currently have, and each fish can tolerate different levels.