Old attitudes about weed are going up in smoke. No one seems to care the US government still lumps marijuana in with hard drugs like LSD and heroin. Over the past two decades, 23 states, including California, have approved pot for medicinal use. Four states — Alaska, Washington, Oregon and Colorado — and the District of Columbia have gotten onboard with reggae hero Peter Tosh, who argued, “Legalize it. Don’t criticize it.”

Make no mistake: America’s going to pot. We’re expected to drop $4.8 billion on weed this year in the states where it’s legal, according to GreenWave Advisors. The cannabis researcher sees total sales rising more than sevenfold to $35 billion by 2020, assuming the entire country removed prohibitions on bud.

As more people spark fatties, money has poured into budding ventures, which investors reckon will grow like weeds.

On a September Tuesday, I dropped by The ArcView Group’s Investor Pitch Forum, where potpreneurs hustled for the attention of moneymen. The pitch forum is a big deal in the world of weed; ArcView is a marijuana investor network with more than 500 members.

Held in a conference room at the swank-if-stiff L.A. Hotel Downtown, the forum is a Shark-Tank-meets-speed-dating beauty contest in which every third word seems to be “cannabis.” Entrepreneurs take the stage, give their version of Hollywood’s elevator pitch and then go table-to-table seeking cash.

Jordan McHugh, co-founder of Denver-based Best Buds, is looking for a half million dollars to support his mapping service, which he likes to call the Tinder of cannabis dispensaries. He wants to stop outsourcing his engineering and hire three developers. He’s willing to negotiate an equity stake.

The investors pepper McHugh, who looks like he might have played lacrosse at a New England boarding school, with questions. What’s your cash burn rate? How do you differ from your chief competitor, Leafly?

McHugh fields the questions and hits the circle of tables. He doesn’t score financing that day, but the experience helps him refine his pitch. He tells me that he later got investors to buy into Best Buds, though he doesn’t say how much cash he got.

The investor activity underscores a shift in the culture of the canna-economy, say longtime marijuana entrepreneurs.

“The ratio of tie-dye to suits used to be 99-to-1,” says Jim McAlpine, co-founder of New West Summit, another weed conference that takes place this week in San Francisco. “Now, it’s more suits than tie-dye.”