MT. LEBANON, Pa. — The owners of Betsy’s Ice Cream in this Pittsburgh suburb have experimented with such ingredients as lavender, candied ginger and lemongrass for their homemade concoctions. Sometimes they’ve been surprised more by what flavors have worked than which ones haven’t.

“The candied ginger didn’t freeze too well,” said owner Ryan Miller. “But the vegan Thai coconut we have right now, which I wasn’t too sure about, is selling like crazy.”

Ditto the lavender raspberry, which Betsy Miller had doubts about. “I thought, ‘Lavender — who’s going to want lavender in their ice cream?’” she said. “But now it’s one of our staples.”

Betsy’s Ice Cream opened in 2012 after Ryan Miller made some ice cream in his own kitchen to bring to summer cookouts and got an overwhelmingly positive response. The shop is in the middle of Mt. Lebanon’s uptown business district, and on a recent evening it had a steady stream of customers seeking a cold treat.

But as with any seasonal business, the joint is not always jumping, Ryan Miller said. They close the store from December to February, doing catering and supplying restaurants with ice cream year-round.

In November, they started a subscription delivery service, modeled after the community-supported agriculture system that lets farms sell fruits and vegetables directly to subscribers.

“We wanted to keep the connection with customers year-round, even though the shop was closed,” Ryan Miller said.

For $20 a month, subscribers get one pint of four different flavors. Ryan Miller said each CSA box contains one of Betsy’s premium flavors and usually includes a seasonal flavor like pumpkin in the fall, as well as a flavor that’s popular with kids such as bubble gum.

Unlike traditional CSAs where subscribers sign up for a season and are locked in, Ryan Miller said Betsy’s subscribers can opt out at any time. “But retention has been really good,” he added.

They have customers all over the region, Ryan Miller said. He hesitated to say how many because he adds a few new customers every day, but said the total was between 50 and 100 people.

Betsy’s deliveries are usually on the 20th of every month. Ice cream pints are placed in a cooler with ice, so they will keep for an hour or two. If a customer expects to be away from home, Betsy’s will coordinate a rain date or a store pickup or, if the customer is on vacation, suspend that month’s delivery.

The Millers do the deliveries themselves. “It’s kind of a nice way for us to spend a couple hours together,” Betsy Miller said.

By contrast, Millie’s Ice Cream in Pittsburgh started as a CSA-only business last year, after seeing strong sales of their homemade ice cream on Friday nights at a cocktail bar in the city, according to co-owner Lauren Townsend.

“We were thinking, ‘How do we keep this going,’ and at first we thought of a delivery service, kind of like the milkmen of a bygone era,” she said. “Then it was kind of like a light bulb went off, that we should try a subscription and call it an ‘ice cream CSA.’”

Their ice cream CSA has been so successful that Townsend and her husband, Chad, are planning to open a bricks-and-mortar shop later this year.

Millie’s runs a different CSA for a limited time each season, with a summer plan set to kick off in mid-July. For $75, subscribers get two pints every two weeks for eight weeks. Their customer base also is between 50 and 100 people.

“The way we pick flavors depends a lot on availability,” Townsend said. “We try to be as seasonal as possible, so in July we’ll have blueberries and blackberries; in August we’ll have peaches.”

She added that most people who sign up are on board with the CSA concept. That is, subscribers never know exactly what they’re going to get with each installment.

“For people with kids, it’s actually a lot of fun, because the kids have no idea what flavor is coming that week,” Townsend said. “We have a lot of very excited kids waiting at the door when we drop off ice cream.”