Legal cannabis is the fastest-growing industry in America, representing $50-60 billion per year. Even Snoop Dogg has jumped onto the bandwagon.

If you're an investor looking for a piece of the pie, here are five industry startups that you want to keep an eye on.

1. Flowhub

Flowhub's seed-to-sale management solution is cloud-based and user-friendly. Their CEO, Kyle Sherman, worked at a grow-op and experienced firsthand the problems with cannabis inventory management: then, he decided to fix them. In the summer, Flowhub got an infusion of investment totalling $500,000 through a seed-funding round, and a deal with MassRoots, the largest online social network for cannabis users.

2. Sweet Grass Kitchen

A self-proclaimed "small-batch bakery," Sweet Grass Kitchen creates and distributes both recreational and medicinal cannabis-infused edibles to over 300 cannabis stores throughout Colorado. They've bootstrapped the venture themselves so far, but we'll keep an eye on whether they go looking for outside investment.

3. Apothecanna

Cannabis-infused body creams and sprays. Relaxing and 100% plant based. Apothecanna are selling their products in Colorado, California, Oregon, and Washington. We won't be surprised if they start getting into more states as legalization spreads.

4. Ganjaboxes

A lifestyle box club for the cannabis connoisseur. A Ganjaboxes subscription gets you a monthly toolbox with all the necessities for enjoying cannabis (they'll even send you different strains, seeds, or edibles if you are over 21). Ganjaboxes is one of Canopy Boulder's fall 2015 companies.

5.MagicalButter.com

A machine that makes a complicated process easy. Magical Butter makes cannabis-infused butter, oil, and tinctures with the push of a button. Garyn Angel, the founder, is selling around 4,500 units a month at $175 a piece. Magical Butter will be looking for investment from private equity, venture capital, and even private investors in the near future.