Sorry if it is a noob question, or has been answered elsewhere before.
I have started growing some plants in a grow tent (is winter here) and over the last couple of days have noticed that some of the lower leaves of one type have started going yellow.
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I am not sure what is causing it.
I water them 2 or 3 times a week and feed them half strength Charlie Carp once a week.
Am I doing something wrong? What should I do to fix it?
All input appreciated.