If Queens is the borough of the world, Astoria is its Mediterranean outpost. On 30th Avenue, where it is easier to order souvlakia on pita than a slice of pizza, and olive oil seems to exist as common currency, you will find United Brothers Fruit Market, the supply store for this enclave along the East River. Its signature yellow bag, a common neighborhood tumbleweed, is carried by Greek grandmothers and hipsters alike.

Met by mist from overhead, nearly 3,000 people troop in and out of this 3,000-square-foot corner store on a daily basis, drawn to the Hass avocados, the yucas, the cauliflower, the tomatillos. And the radicchio, and the endives. On a recent Wednesday evening, Sophia Konstantinides, 65, was one of them.

Every day around 11 p.m., Ms. Konstantinides stocks up on vegetables for a late-night dinner and the next day’s leftovers. She lives on Long Island but grew up in Astoria, and United Brothers is the only stop on her way home from her job in Manhattan, where she works late as an insurance broker. “I pop into Queens, do my shopping and then hit the parkway,” she said, cradling a head of broccoli like a bouquet. “It’s like I came home with flowers.”

The market is open 24 hours a day, every day of the year. But even at dawn, a line slinks along 33rd Street, underneath the store’s yellow and green awning. Customers are scrambling to pick up stragglers in the discount bin, where items are 29 cents a pound. Recent bargains: (somewhat soft) red tomatoes, (strangely shaped) blue broccoli and iceberg lettuce (a bit browner than its usual Arctic hue).