Scotts Miracle Gro (SMG - Get Report) has received the "upgrade of the year," according to TheStreet's Jim Cramer, co-manager of the Action Alerts PLUS portfolio.

Shares are up 5.5% Thursday after the company was upgraded to buy from underperform at Bank of America/Merrill Lynch. Analysts assigned a $105 price target, Cramer said on CNBC's "Mad Dash" segment. 

While the company is known mostly for its fertilizers, the analysts have identified its hydroponics division as a serious growth opportunity. That's why they upgraded to buy from sell, Cramer reiterated. 

Hydroponics also allows for the growth of cannabis, a market that is rapidly growing now that states are legalizing the product, Cramer said.

The analysts even said pot could be a $1 billion category that's at the precipice of secular, multi-year growth. That's a big deal for a company like Scotts. 

Because of this wave of growth, the guidance from Scotts Miracle Gro is likely conservative and plenty of growth remains ahead for the company, Cramer concluded. 

At the time of publication, Cramer's Action Alerts PLUS had no position in companies mentioned.