Mark Wahlberg and Gronk Put on Garden Gun Show at Miami Restaurant

Rob Gronkowski and Mark Wahlberg officially went GANG GREEN on Tuesday ... but don't freak, Pats fans -- we ain't taking about the Jets.

Marky Mark and the NFL superstar hit up David Grutman's new plant-based restaurant Planta in Miami for a completely green meal ... and even hand-picked their own herbs from the rooftop garden.

FYI -- the camera crew is filming for Mark's reality show, Wahlburgers.

Of course, the 2 health freaks used it as an opportunity to show off their guns. (Who says ya need meat to be ripped?)