Help Me Diagnose My Plants (First Grow)

This is my first ever grow, so I'm a little bit clueless. My partner left about a week and a half ago, and wont be back for three. Some of our plants are not looking too happy, I have no clue why but suspect I over fed them. I didn't completely understand how dry I should let the plants become. The only fert I'm using is "Yates Thrive All Purpose" Can you please help me bring these plants back to good health? Thanks

I don't think they dig the soil so much. Hard to say, sort of cryptic presentation of the problem.