Lucy Keepper has a lot of slime to make before Sept. 21.

That’s when the Minneapolis 14-year-old is hosting the first-ever “Slimesota,” an event for slime enthusiasts like herself, who love to create, mix, trade and squish the oozing material.

“I’m hoping I can get 150 slimes ready to go,” she said. “It never hurts to have too many.”

Keepper was inspired by an August family trip to the Midwest Slime Fest in Kansas City. She tried, unsuccessfully, to find a place closer to home where she and her slime-slinging friends could buy, sell and swap slime.

“I was looking everywhere. And I spent a couple of days looking and there wasn’t anything. So I was like, ‘Well, you know what? I’ll start my own slime event,’ ” the Edina High School freshman said.

She lined up a sponsor (the Minneapolis store Kinoko Kids), found a venue (Lake Harriet United Methodist Preschool, where she once attended) and rented the school’s event room from 11 a.m. to 4 p.m.

Then, she decided on a price for tickets — $8 for general admission and $18 for a VIP pass, which includes raffle tickets and slime samples. Parents are admitted free, but attendees 13 and under are required to be accompanied by an adult. Keepper said 15% of proceeds are going to Secondhand Hounds, a dog rescue group.

After posting about Slimesota on Instagram, she was able to attract vendors, whom she’s charging $30 each to participate.

“I have 17 slime vendors all lined up with over, I think, 60,000 followers on Instagram, which is really cool. And they’re from five states,” she said.

Keepper plans to set up a booth herself, but she persuaded her older sister to staff it, since she will be busy managing the event, which will include a slime trading station and demonstrations, she said.

“There’s a stage, so some of the sellers will go up and they’ll show how to make some of their favorite slimes for everybody. And they can watch and kind of learn how to do it.”

This is Keepper’s first slime rodeo, although she has “sold slime online before and like, just to friends. But this is my first time planning something big — other than a birthday party,” she said.

So she’s getting some advice from her dad, Dave, who works in advertising and marketing. Keepper said that she made all the phone calls and handled most of the arrangements herself.

Keepper developed her own slime recipe and perfected it in 2016 after watching YouTube videos (she uses liquid starch as her activator) and launched an Instagram account called @curious.slimery.

“Slime can give kids a reason to be super-creative. There’s, like, some different textures, colors, but you can literally make anything when you’re thinking about slime,” she said. “Also, like when you’re playing with it, it’s very nice and calming and stress-relieving.”

Slime is big online, she said, but in-person events are “more fun.”

“Instagram is like, the biggest place that is so many slime accounts. I can’t even count,” she said. “But online, you don’t really get to meet the slimers and hear about their background stories and everything.”