Its nickname is "the Walmart of weed."

Described as the nation's only hydroponics franchise that openly talks about medical marijuana, weGrow opened a 21,000-sq.-ft. store in Phoenix earlier this month. 

The growing chain does not actually sell any marijuana itself, just everything one would need to grow it, according to Dhar Mann, founder of weGrow. The concept already has two locations up and running in Oakland and Sacramento. A Washington, D.C., franchise and Tucson, Ariz., franchise are coming soon, according to the company's website.

The store features a large selection of hydroponic supplies, and also offers a variety of services aimed at educating medical marijuana cultivators, including live grow demonstrations with real plants, an on-site doctor for medical cannabis evaluations, expert technicians to teach safe and responsible grow practices, and even an on-site laboratory to test cannabis before patient consumption.