John Legend’s Get Lifted Film Co. is planting a documentary about four “gangster gardeners” who discover what happens when they get their hands dirty — in the soil of South L.A. Check out the trailer for Can You Dig This, which has its world premiere Thursday at the Los Angeles Film Festival. Fusion already has nabbed TV rights to the pic about the urban gardening movement, which was cultivated by director Delila Vallot. It also features a new original song written and performed by defending Best Song Oscar champ Legend and additional music composed by TV on the Radio’s David Sitek.