The Rocky Mountain state becomes the first jurisdiction in the world to allow the sale of pot for recreational use

Tim Cullen gave up being a high school biology teacher to enter the marijuana business after he and his father were diagnosed with Crohn's disease. He used his knowledge of botany to grow and harvest plants, which treated the condition and eased the pain, and built a business out of it.

By coincidence around the same time the TV show Breaking Bad depicted a fictional high school chemistry teacher, Walter White, morphing into a meth drug lord after being diagnosed with cancer.

Growing and selling pot for medicinal purposes was legal in Colorado but had a shadowy, seedy image. Cullen did not broadcast his career switch. “I didn't tell former colleagues. I kept it to myself. I was afraid how people would judge – not necessarily me, I've a thick skin – but my son.”

That fear will melt on Wednesday when Colorado becomes the first jurisdiction in the world to legalise recreational cannabis sales, shining a sudden spotlight on Cullen and dozens of other retailers across the state.

While the Netherlands has allowed the sale and consumption of small amounts of marijuana in “coffee shops” since 1976, it has never formally legalized sales or growing, unlike Colorado which is the first place where marijuana will be legally produced, sold and taxed in state-licensed venues, in a system similar to that used by most countries for alcohol regulation.

“The genie is fully out of the bottle. If people don't like it, well, I'm not going to care about it any more,” said Cullen, 41, as staff at his Denver store, Evergreen Apothecary, bustled in anticipation of new customers and regulatory challenges.

Sporting a blazer, striped shirt, jeans and loafers, he looked every inch the successful entrepreneur. Cullen said his son will have no reason to be ashamed as he grows up – unlike Breaking Bad's family trauma. “It'll be no big deal when he learns what dad does for a living.”

Supporters and opponents of Colorado's initiative agree that Wednesday is the start of a rather big deal: a landmark challenge to decades of “drug war” dogma which is expected to embolden other states to follow suit, potentially heralding a shift as radical as the end of alcohol prohibition in 1933.

Colorado voted to allow recreational pot sales in a ballot initiative in the November 2012 general election, as did voters in Washington state. Uruguay also recently decided to legalise. As the first to put the law into practice the Rocky Mountain state is a laboratory commanding global attention. After Washington, activists in Alaska, Oregon and Nevada hope they will be next.

“This is a very momentous occasion. A huge milestone in the movement to end marijuana prohibition,” said Mason Tvert, communications director for the Marijuana Policy Project. In the Netherlands pot is tolerated, but not legal, a crucial distinction, he said. However many show up on Wednesday to buy recreational cannabis – estimates vary from dozens to thousands – they will be “part of history”, said Tvert. He praised state authorities for efficiently converting the voters' verdict into nuts-and-bolt reality.

Questions abound: will zealous regulation strangle the launch? Will stoners celebrate in the streets and provoke a police crackdown? Will tourists swamp the stores? As weeks and months pass, and recreational pot becomes more available, will Colorado be seen as a showcase for a responsible industry that obviates mass incarceration for minor drug offences and generates hundreds of millions of dollars, or will it be deemed a fiasco, evidence that the US's 1937 marijuana ban was wise after all? If the latter, federal authorities could curb the experiment since federal law still bans the substance.

Much hinges on the ability of Colorado's dispensaries to adapt. From serving a relatively stable pool of 110,000 patients with medicinal red cards those with recreational licences must now serve a much bigger, fluid market while jumping through myriad new regulatory hoops intended to track every marijuana plant from seed to sale.

Each plant clipping must be tagged with a unique serial number as it flowers and is harvested, weighed, dried, trimmed, packaged and transported. Stores must record each sale and have a set number of cameras with certain pixelation, among other security requirements.

It is a formidable list but the industry, eager for mainstream acceptance, has assented. “We are the only industry that has lobbied for regulation and taxes because we realise that's what we have to do if we are to keep the Department of Justice at bay and keep public opinion on our side,” said Michael Elliott, executive director of the Medical Marijuana Industry Group.

He complained, however, that the Drug Enforcement Administration had pressured security firms and banks to shun the industry, leaving it vulnerable to criminals and unable to claim tax deductions on payroll and other costs.

Colorado has issued 348 recreational pot licences, comprising 136 for retail stores, 178 for cultivation, 31 for infused edibles and other spin-off products, and three for testing. An administrative backlog means only about 40 stores are expected to start selling recreational pot on Wednesday. Doors open 8am local time.

'People are going to open up their eyes'

How many are ready for prime time remains to be seen, but if Cullen's Evergreen Apothecary store is any guide, recreational pot's legal debut should go smoothly. The former teacher has installed extra points of sale, hired extra employees, trained staff to educate a new breed of customer unfamiliar with pot shop etiquette (no photographs, no consuming on the premises), stocked up on child-resistant bags, received official tags and liaised with police and the Colorado Department of Revenue's marijuana enforcement division.

To enter the store you need to show and swipe ID. Once inside it could be Starbucks – clean, bright, hardwood floors, coffee-shop music, products and prices marked on blackboards – except for jars of green buds marked with names like Bubba Kush, Perplex, Afghooey and Red Diesel, plus infused edibles such as CBD-enriched “Mountain High Suckers” lollipops and Karma Kandy Creams. You can also buy glass pipes and books with titles like The Marijuana Chef Cookbook, Marijuana Made Simple and Teaming with Microbes.

Medicinal customers – ranging from twentysomethings in baseball caps to senior citizens with body braces - streamed in on Tuesday to stock up lest recreational buyers clean out limited stocks.

The business was ready, said Cullen. “We've been fortunate that we've been able to comply with all the rules.” Pot's black market will disappear and the stigma will ebb as opponents see the sky does not fall, he predicted.

Staff in Evergreen Apothecary and Colorado Harvest Company, another Cullen co-owned outlet which is due to start recreational sales in a few weeks, shared the optimism.

Jahni Denver, 28, a head “bud tender” who advises medicinal customers about different strains, tastes and effects was looking forward to sharing his knowledge, sommelier-style, with recreational customers, including out-of-state friends who promised to visit later this year. “People are going to open up their eyes.”

Some employees were flattered but slightly unnerved by the media attention because their parents do not know they work in a pot dispensary.

“I tell them I work for a herbal wellness store,” said Laura Mulloy, 25, a nutrition and psychology student from Kentucky, as she sorted the new child-resistant bags. “But I'm getting to the point now that I'm not ashamed of it.”

Seeing how cannabis alleviated people's pain, and how the legalisation forces had prevailed, had transformed her view, she said. “I feel it's our movement. It's pretty incredible. We're an example for the rest of the country.”

Highs prices

As of Wednesday, there are a number of marijuana recreational products available to anyone aged over 21 to buy in Colorado. State residents are limited to buying an ounce (28 grammes) at a time while non-residents can only buy a quarter of that amount.

Below are some of the options provided by licensed sellers (all prices are subject to an additional 21% sales tax).

• Pre-rolled joints, $10 each. A typical joint contains less than 1 gramme of marijuana.

• 1 oz Indica or Sativa buds: “best”, $179; “better”, $169; “good”, $159.

• Glass pipes: $15-$30.

• Marijuana-infused pomegranate “elixir” drink (75mg): $14.

• Marijuana spearmint dew drops (100mg): $20.

• Marijuana truffles (50mg): $10.

• Marijuana chai mints (100mg): $11.

• Marijuana massage oil (100mg): $14

• Marijuana pain relief lotion

(100mg): $18.

• Marijuana bath soak (100mg): $18.