It looks like the first medical marijuana dispensary will open in Salem. But Alternative Therapies Group, Inc. (ATG) must clear several hurdles before it rings up a sale of marijuana for medical use. The certificate announced Wednesday allows ATG to plant seeds at its cultivation site in Amesbury.

Assuming a three-month growing cycle, the storefront in Salem could begin selling marijuana in April. But the plants must be tested for mold, heavy metals, pesticides and potency. State officials say they will review dispensary labeling and transportation plans, as well as conduct unannounced inspections, before the dispensary is allowed to open for business.

Some patients have criticized the state for a slow roll-out of the medical marijuana law voters approved in 2012.

"While this process has taken some time, we wanted to make sure that we got it right, this is a brand new industry," Secretary of Health and Human Services John Polanowicz said.

Fourteen dispensaries are still under review for certification.

Salem Mayor Kim Driscoll said in a statement she's pleased that a dispensary in her city has received the state's first medical marijuana certificate.

"Salem has long been a progressive, forward-thinking, and open-minded community and we look forward to ATC starting operation and providing yet another critical medical choice to patients for the entire North Shore," Driscoll said.

And in Amesbury, "I am happy to see them [ATG] reach this milestone," said Mayor Ken Gray. "I look forward to seeing ATG develop as a positive contributor to the Amesbury community."

WBUR's Martha Bebinger contributed reporting.