I will be installing a 60amp sub panel in my hoop house greenhouse that I just built and am not sure what exactly I need to buy to run 140 ft direct burial from the main service panel(the power pole itself) to the sub-panel in my greenhouse. I'm not sure what cable(s) I need to get exactly, I believe I need 6AWG but I don't know what I need to ask for exactly at Home Depot. Do I get something with 2 hot, 1 neutral, and 1 ground cable and run all of that underground to my sub-panel do I need copper or aluminum? I'm a little overwhelmed with all of the different types of cables.
Also, it sounds like I need to install a grounding rod at the greenhouse as well, so I just run a copper wire from the grounding rod straight to the sub panel as well as the cable from the main service panel. I guess they would both just be installed inside the sub-panel on the same grounding bar?
Thanks for your help