A group of children watched as Adam Bierton made his first few slashes into the meat of a pumpkin at the New York Botanical Garden earlier this month.

Using a tool that resembled a carrot peeler, Mr. Bierton scored a horizontal eyebrow ridge and the grooves of a frown. Over the course of three hours, a steady crowd of about 20 people looked on as heaps of orange pulp formed at his feet. Every so often he spritzed the pumpkin’s facade with a bottle of lemon juice to keep its flesh dewy.

“It looks like Javier Bardem,” Jasmine Taby, a 24-year-old college student in the Bronx, said as she watched the face being carved.

Mr. Bierton, 40, is a pumpkin carver who expects to carve more than 100 pumpkins this fall. His pumpkins appear to be snarling or wailing, and often have bulging eyeballs that he scoops from russet potatoes using a melon baller. Unlike hollowed-out jack-o’-lanterns, most of his carvings have their guts intact and are not lit from within.

His interest started in childhood, partly from watching his father carve. “My household was very creative because my mother was a hairdresser and my dad was a photographer,” he said. “My dad was always doing really outlandish jack-o’-lanterns, like, turning them upside down. He would always grab the deformed pumpkin.”

Later, as a student at the School of the Arts in Rochester, N.Y., he began sculpting with clay, plaster and metal. He brought tools for making ceramics home from school so he could use them on pumpkins. After honing his technique under the tutelage of other carvers, he was part of a team that won a season of “Halloween Wars,” a pumpkin-carving competition show on Food Network, in 2015.

Now Mr. Bierton, who still lives in Rochester, is one of a handful of artists who carve professionally throughout a frenzied season that begins in September and ends on Nov. 1.

He has been doing weekend demonstrations each fall since 2018 at the botanical garden in the Bronx, where the edited interview below took place. Time pressure, he said, is far from his only challenge.

“I’m actually mildly allergic to pumpkin,” he said. “It’s like, I love something and it fights me. Maybe that’s why I’m so attracted to it.”

How did you go from an amateur to a professional pumpkin carver?

I had a tradition where every single year I would do an eight-hour carving. The first one I did was Beetlejuice, that was probably in 2000. I did it primarily with a paring knife and an X-acto blade. In 2012, my mom sent me a story about the Maniac Pumpkin Carvers, a pumpkin-carving team, and I reached out.

Wait, what’s a pumpkin-carving team?

Well, there are very few of them. Maniac Pumpkin Carvers are two guys, Marc Evan and Chris Soria, who bring in artists during the season. They primarily do etching work, which is a style of carving where you’re peeling the skin and illuminating the pumpkins from the inside. I worked for them for a couple of years.

How many top-tier carvers are there in the United States?

I think there are fewer than 20 of us that are on the same level. And then there are another 20 that are up-and-coming.

Walk me through your carving process.

I bathe all my pumpkins and store them with a fan blowing on them so bugs don’t get in there. Then the first step is to to peel the pumpkin. You remove the hard orange skin, which allows access to that beautiful flesh that’s underneath, which is great for sculpting. Next I’ll block in the face with a ribbon tool. I’m kind of playing with perspective and drawing with shadow: the deeper the cut, the darker the shadow. Gradually, I start to work with smaller tools, and I finish with knife work.

How do you make money carving pumpkins?

Working live events. My contract with New York Botanical Garden is the majority of my season. And then a lot of the other work is with brands that are looking for pumpkins for promotional use on social media — like logo pumpkins and time-lapse stuff. I’m working with Starbucks and the BBC this year.

How much do corporate clients usually pay for pumpkins?

A pumpkin can range anywhere between $400 and $5,000. I have a dream to replace my entire year’s salary with the pumpkin season. I’m not quite there yet.

What do you like about pumpkins as a medium?

Every single pumpkin is unique, and the material changes. It’s not a consistent medium like wood or clay. I don’t usually have a design before I have a pumpkin — the size and shape leads into the design. I also love the ephemeral part. I have to create something that I can’t keep.

Do you carve other stuff — zucchini?

I don’t have any interest in, like, watermelons or stuff like that. I don’t know why. I should totally start working with another medium that doesn’t decompose in two days.

Do you get V.I.P. pumpkin patch access?

Oh yeah. I have a very close relationship with the farmer at the pumpkin patch I go to in Rochester. We start talking early in the season and he tells me how the crops are. I have to be their best customer. I’m spending hundreds and hundreds of dollars on pumpkins.

What does the inside of your fridge look like?

I have an industrial fridge that has a glass front. It’s filled with carvings. And all of my pumpkins are wrapped in Saran wrap, which adds a whole other layer of creep. I have all my guys in there and they’re screaming at me.

What do most people do wrong when carving?

The biggest mistake is cutting a hole in the top of the pumpkin.

Say more!

Something I learned is to go in through the back, by cutting a big square or an octagon. Cutting a hole in the top of the pumpkin takes away from the character of a long, ornate stem. People cut the bottom too. That’s no good, because the juice ends up everywhere.

How do you decorate your own house for Halloween?

It’s all pumpkins. I don’t get in with the tacky stuff. There’s no blown-up spiders, even though my wife tries to bring that stuff home.

Do friends ask you to carve pumpkins for them?

All the time. I don’t have time for that! I don’t think people understand that I spend six hours on a single carving.

How long will the pumpkin you carved today at the botanical garden last?

Because I haven’t opened up the cavity of the pumpkin, it has a good chance of lasting up to two weeks. It depends on the freshness of the pumpkin and the elements it’s in. If it’s in the beating sun and there’s bugs and squirrels? See you later.

How do you manage the time pressure that comes with the job?

I don’t sleep in October. I’m doing two or three pumpkins every single day. It’s exhausting, but there’s just no other way because it’s a time-sensitive medium. I try to tell all my corporate clients, like, let’s shoot in November and we can use it for 2024. They’re like, nobody’s thinking about next Halloween.

What do you do the other 11 or so months of the year?

I own a fried-chicken restaurant in Rochester.