Help me diagnose my plants and get me a better yield!

[athelar]

These are my plants. This is my second grow cycle and i am still a beginner gardener
The bottom leaves are falling off and the top leaves are curly. I dont know what to do and i think the buds have stoped growing. They are just turning brown and i am gona harvest soon. I want to know if i can fix anything to get a better yield. I am not using any nutes.

 

[Dutty Panty]

What kind of soil?
What kind of lights?
Why no nutrients?
How often you water?
What strain?
What's the average relative humidity and temp?

How long on a 12/12 light schedule now.