ok i got like 8 plants in this resovoir "lowrider" and one is ready to harvest but the roots are tangled to the one next to it that has about 12 weeks im guessing should i cut my finished plant and leave its roots or wait two weeks or what should i do here? thanks
Cut it and then after see if you can separate the roots. If not leave it for a couple days and try to pick/ cut the dead roots out. You do not want to leave them in there the whole time they will die/brown and then rot and if left alone the rotting will affect the healthy roots and the plants that are still up.
If you just cut off your buds and branches with buds, and leave some of the leaves, it will stay alive a while longer, plenty long enough for your others to finish up.