In November, voters in as many as 12 states will see a marijuana legalization initiative on their ballots. Marijuana is already legal for recreational use in Alaska, Colorado, Oregon, Washington and Washington, D.C. Another 25 states have legalized medical marijuana. The era of marijuana prohibition is rapidly coming to a close.

Unfortunately, lawmakers lack easy answers to tough questions facing the marijuana industry. Legalization presents challenges on a number of fronts, including distribution, taxation, consumption, security and public health.

In a recent article, I argue that the agricultural sector of the marijuana industry also presents a number of challenges. One paramount question looms over the rest: Will marijuana agriculture become consolidated, with “Big Marijuana” companies producing vast quantities of indistinct marijuana? Or, will small-scale farmers thrive by producing unique and local marijuana strains?

My research shows that Big Marijuana is not inevitable. On the contrary, a local, sustainable, small-scale farming future is entirely...