On the eve of a vote that could legalize recreational marijuana in Massachusetts, a Colorado company is preparing to build the state’s largest marijuana greenhouse, a sprawling, high-tech complex that could eventually expand to nearly 1 million square feet.

Denver-based AmeriCann Inc. completed a deal last week to lease a 53-acre parcel for the project near Route 24 in Freetown, where officials have welcomed the company’s proposed Massachusetts Medical Cannabis Center as a potential economic boon.

The facility, to be built in phases over several years, is designed to bolster the state’s struggling medical marijuana program. But if voters here decide on Nov. 8 to legalize the sale of marijuana for recreational use by adults, AmeriCann expects to accelerate construction and would likely rent some of its cultivation space to a retailer of recreational cannabis. [Read more at Boston Globe]