my marijuana leaves are turning yellow please help

It's a root rot! The soil is too wet :) don't water until 2-3cm of soil are dry , is better little bit water every 2-3 days, not a big watering once a week for example :) cut of damaged leaves, and check drain water ec and pH

No diary = no information. Since the yellowing is in the new growth, not the old, you've got a deficiency of one of the mobile nutrients (not NPK) and need to fix that - but again, with no diary we have no information that will help us guide you. Start a diary.... reconstruct as much information as possible going back at least 2, hopefully 3 weeks and come back with your question... Good luck

Looks like huge nitrogen lockout. You overfed them, now aftermath comes ... But could be root issue too. Hard to tell only from pictures ...