Nitrogen problem, pretty basic one :) Lower leaves get yellow first, cause plant keeps transporting nitrogen upwards to support the new growth and nitrogen is the most mobile nutrient there is. Organic treatment includes compost tea, topping with EWC and even a dash of ammonia or urea. You're female is in early flowering and she still needs a lot to continue photosynthesis!
BTW I'd like to promote #420help hashtag for those growers who need a hand and those who can stretch it :)
General thing seams it was nute problem so I gave it some medi one I had and it has not showing signs of getting worse.
I have been doing some research in organic as I want to get to that at one point
If you need any advice for starters, just follow me. I'm posting a lot of stuff about #organicweed already and a lot more is coming!
Will be following I am going to be switch to a fully organic grow with live soil next grow I do believe. I will be doing more research in to no till living soil over next week to see what I will need to start my ecosystem.
Any tips if growing this way before let me know
I'm gonna make a post on how to start off