A lot could change for the cannabis industry over the next six months. In Canada, the new cannabis derivatives market could pick up momentum -- or not. In the U.S., the November elections hold the potential to set the stage for potential marijuana legalization at the federal level or push back any such hopes for several more years. What happens next with the COVID-19 pandemic could make the biggest impact of all.

With all of these uncertainties, marijuana stocks could be highly volatile for the rest of the year. Here are three top marijuana stocks, though, that appear to be great picks to buy for the second half of 2020.

Three cannabis leaves on a red line trending upward

Image source: Getty Images.

1. Innovative Industrial Properties

Innovative Industrial Properties (NYSE:IIPR) ranks as one of the few cannabis stocks that performed well during the first half of 2020. Shares of the medical cannabis-focused real estate investment trust (REIT) jumped 16%, albeit with some big up-and-down swings along the way. I think IIP should be able to keep up its winning ways over the next six months and beyond.

There are really only two things necessary for IIP to continue generating strong growth. First, the company needs to add more properties. Second, it needs to continue collecting rents from its existing tenants. Both should be easily achievable.

IIP has already added 12 properties so far this year and leased them to medical cannabis operators. The company should have plenty of cash to fund more deals thanks to its recent stock offering that raised gross proceeds of nearly $259 million. 

Thus far, only three IIP tenants have had any problems with rent payments as a result of the COVID-19 pandemic. IIP worked out rent deferral agreements with each of these tenants but shouldn't forego any revenue. Many medical cannabis markets across the U.S. are booming. IIP's future revenue stream should be reliable.

2. Green Thumb Industries

During the worst of the stock market crash in March, Green Thumb Industries (OTC:GTBI.F) shares plunged nearly 60%. But the stock rebounded impressively, with GTI stock now up year to date. My view is that this momentum will continue.

GTI delivered sizzling growth in the first quarter. Revenue soared more than 35% quarter over quarter. The company benefited especially from a strong launch of the adult-use recreational marijuana market in its home state of Illinois. 

While GTI isn't profitable yet, it's getting closer. It posted earnings before interest, taxes, depreciation, and amortization (EBITDA) of $20.3 million in Q1 with adjusted operating EBITDA of $25.5 million. Both numbers reflected significant improvement from the previous quarter.

At the end of June, GTI opened its 47th retail cannabis store in Duncansville, Pennsylvania. It has licenses for another 49 retail locations, giving the company a clear runway to deliver more growth in the future.

3. GrowGeneration

GrowGeneration (NASDAQ:GRWG) took the prize as the best-performing marijuana stock in the first half of 2020. Shares of the specialty hydroponic and organic gardening retailer skyrocketed 67% higher. I wouldn't necessarily count on that kind of performance in the second half of the year. However, I like GrowGeneration's chances of delivering solid returns.

The company reported record revenue for the first quarter of $33 million. That was GrowGeneration's 10th consecutive quarter of posting record revenue. It hasn't achieved profitability yet. However, GrowGeneration reported all-time high adjusted EBITDA of $2.7 million in Q1. And had its new executive share-based awards not been front-end vested, the company would have been profitable in the quarter.

GrowGeneration recently acquired the assets of H2O Hydroponics, the largest hydroponic garden center in Lansing, Michigan. Look for more deals to come: The company raised gross proceeds of around $42 million in a stock offering earlier this month. It plans to use the money in part to fund expansion through acquisitions.

With 27 retail stores across 10 states, GrowGeneration ranks as the largest chain of stand-alone specialty hydroponic and organic garden centers. The company's goal is to expand into all of the major states in the U.S. and in Canada. As more states legalize cannabis, GrowGeneration should have tremendous long-term growth prospects.