what is causing this

out door plant and seems really healthy . I only give it nutes about 1 every 2 weeks as this is my first grow and dont want to mess up. All other leaves are nice and green but dont know why the bottom leaves are turning. Would yall just cut them off? Could it be lack of sun just not getting to the bottom Leaves?

Yeah its just normal ageing. Bottom ones turn yellow as new growth comes on. Once they're yellow just carefully remove them.

do I cut them at the main stem? or right next to the leave?