Innovative Industrial Properties (NYSE: IIPR) is a smart passive income stock thanks to its ever-growing empire of marijuana cultivation real estate. In fact, with a relatively small weekly commitment, you could build up a pretty decent haul of dividends annually, and it wouldn't even take you that long to do so in the grand scheme of things. Before we go over the details of how to do that, let's start by taking a minute to appreciate why this real estate investment trust (REIT) is such a passive income machine in the first place.