Possible Nitrogen Deficiency?

If u can measure the soil ph u can do a perfect job of this. Ur soil ph levels should be between 5.8 and 6.2. 5.8 early days and 6.2 towards the end. But obviously the pH of the water u add means nothing if the media is not the right levels for the plant to be able to take the nutrients it needs. U can find charts for the different types of media ie. Soil, coco and probably more, with a pH chart for the different nutrients. If ur like me and like to know the chemicals then that's the best piece of information u can have.