Mike Wondolowski often finds himself in the middle of it. He may be on the chaise longue on his patio, at his computer in the house, or tending to his orange and lemon trees in the garden when the powerful, nauseating stench descends on him.

Mr. Wondolowski lives a half-mile away from greenhouses that were originally built to grow daisies and chrysanthemums but now house thousands of marijuana plants, part of a booming — and pungent — business seeking to cash in on recreational cannabis, which has been legal in California since January.

“If someone is saying, ‘Is it really that bad?’ I’ll go find a bunch of skunks and every evening I’ll put them outside your window,” Mr. Wondolowski said. “It’s just brutal.”