“There’s hundreds, easily,” he said. “I started with succulents and then it turned into tropical and indoors. It’s relaxing to go home and get your hands dirty – in dirt.” He says if he and his partner, Dou Ribu, sold them all they would have enough for a house deposit. Ribu, who loves bonsai, says they are not the only ones. “Young people are getting off the smashed avo and into plants,” he quips.

Millennials’ love affair with houseplants has been gaining momentum worldwide but now southeast Queensland nurseries say the intersection of shrinking backyards, drought conditions and social media hype means young people are flocking to their businesses.

In 2018, indoor plant sales represented about 15 per cent of Chadwick Nursery’s business at Loganlea but by the end of last year it was 65 per cent. The demand was so high that millennial owner Ryan Chadwick, 35, increased indoor growing at his Greenbank grow site by more than 50 per cent. The surge in houseplant sales coincided with the two other crucial jumps – the average customer count more than doubled from 180 per week to 400 and the nursery’s profits rose 20 per cent. “It’s 100 per cent houseplants,” Chadwick says.

He says 20 to 35-year-olds are “definitely the biggest growth area”.

“In the past, plants were seen as your grandma’s thing. That’s reversed,” he says. “It’s the young people who are up on a Saturday morning, curing the hangover with a brand new plant baby. It’s your L-plates before you have a baby.”

“It’s actually – in an industry that’s hurt with the drought – houseplants have carried us through.”

He says outdoor plant sales dropped as people became cautious about water use. He also concedes the drought may encourage more people to buy indoor plants, which mostly need to be watered no more than once a week.

Chadwick says Millennials’ attraction to indoor gardening is due to plants’ positive effects on air quality and mental wellbeing and how beautiful they look as home decor. At the forefront, though, is that the rise of higher density living in southeast Queensland and loss of backyards does not stop the human desire to be surrounded by nature.

“You don’t have the room for these large lush gardens our parents had. Patio gardens and indoor gardens are a way for people to still feel they’ve got a space outside without actually having that outside space,” he says.

Indoor gardening is an Instagram-worthy hobby, and rare and coveted houseplants, shared and fawned over on social media, can fetch high prices.

“It’s definitely contagious,” he says. “I think there’s a bit of FOMO (fear of missing out) about it – somebody sees their friend with a really great plant set-up and they think ‘I could do that’.”

He says aficionados will snap up the “very much on trend” variegated monstera for $150 to $400, while the anthurium crystallinum, which has leaves that shimmer, sells for $700 to $800. A small philodendron ilsemanii with just three to four leaves can go for $2000.

Every Saturday Chadwick hides expensive specimens around the nursery at rock-bottom prices in a marketing play that means when he opens at 9am, up to 60 people are outside ready to hunt them.

In Brisbane’s southwest suburbs on an overcast Friday afternoon, 85 people and counting line up outside Oxley Nursery. It has taken two years to ensure there are enough specimens for the rare plant sale and it is about to net the nursery 259 transactions – a Saturday or Sunday’s worth of business in two-and-a-half hours.

Enthusiastically greeting everyone and explaining the rules – four rare plants per person, please – is 25-year-old sales manager Nathan Little. His love of plants grew in his Grandmother’s garden. Now, he owns a property with more than 70 fruit trees and has a palpable passion for his job.

“As a young person in the industry, I’d like to encourage other young people to join the industry and if not, to take up a love of plants,” he says.

Houseplant sales are the highest growth category at Oxley Nursery, nearly doubling in two years. Its second and third most common “check availability” requests are for indoor plants: the peperomia prostrata or string of turtles and peperomia argyreia or watermelon peperomia. The top request? “The one thing we can never underestimate as a nursery is screening and privacy,” Little says.

People chat in the line, especially to those they recognise from the last rare plant sale or Facebook groups, like SEQ Crazy Indoor Plant People Australia (C.I.P.P.A).

“Plants in an environment make you happy. Plant people are generally happy people,” says Little.

The first in line, Matt and Deanne Dorrington, arrived at 11.30am with a picnic lunch for the 5pm start. A handful of people down from them is Yen-Rong Wong, 25, with tiny plastic potted plants dangling from her ears and a vine tattooed above her knee. Dylan Blonde and Dou Ribu are there, too.

Deanne Dorrington started collecting plants barely a year ago. “It is a crazy-person thing,” she says. “It’s an addiction, it’s better than smokes or drugs or drinking. The house looks beautiful, it’s really colourful.” The couple walk out with eight lush plants that cost around $400.

Wong says there is a sense of accomplishment to making something grow, quite simply: “gardening is fun”.

“If you would ask me why it’s appealing to young people nowadays, it is there’s so much variety,” she says. “I’m a big fan of philodendrons but not so much caladiums and alocasias. If you don’t connect with the plant you won’t look after it.” She is not sold on the idea that plants are practise babies.

Back at Loganlea it is practice that paid off for Chadwick and his wife, Keren, who welcomed baby Belle after nearly 15 years of marriage last March. Her dad says she, like Little, will grow up surrounded by plants.

“The nursery feels like home. It’s our garden.”