In his painting, Charles Unger has been in an abstract Miles Davis “Kind of Blue” period, so when it came to the closing party for a show atHayes Valley Art Works, Unger brought his trio and stood outside the gallery playing the classic “All Blues” from that album.

“It’s fabulous to have both going at the same time,” Unger, 71, said as he stood outside the San Francisco gallery, which is an 8-foot by 20-foot metal shipping container. “This is like an oasis, considering what it once was, which was a freeway.”

海耶斯谷艺术品狭长strip of city-owned land that was once beneath the Central Freeway and, since the freeway came down, has been slated for development into housing that has not quite happened. So it has been a temporary art garden and even more temporary indoor gallery on a day-to-day basis for five years under the guidance of Barbara Early. With her volunteer team of curators and gardeners, she runs a full schedule of exhibitions, and her summer show was extended to make up for time lost when a bigfiregutted the building on the other side of Oak Street last month and the intersection was closed for weeks.

The show of nine mostly emerging or overlooked artists, which closed Sunday, Sept. 10, with an artist reception, was called “Midsummer Dreams.” You’d have to be a dreamer to think you could host a stylish and sophisticated art event — with live jazz — in a metal box on a forsaken strip of dirt behind an 8-foot cyclone fence, with three lanes of northbound Octavia Boulevard intersecting with three lanes of eastbound Oak Street at the corner entrance to the gallery.

“You got cars and motorcycles whizzing by. You’ve got dogs barking,” Unger said before the start of his set. “You’ve got everything to contend with.”

This includes dust and leaves. The gallery has to be swept out and raked out before it can open.

“It’s just like a regular gallery, except we don’t have full-time staff and we don’t have a bathroom,” said Early, who has a day job as a property manager. “Plus, we’re almost outdoors. That’s different.”

Hayes Valley Art Works once commanded more spacious land withthree or four containers on a large vacant lotfarther up the hill. But that parcel got built upon, forcing the operation to roll downhill to this narrow side lot, with just one container surviving the trip.

“It’s a labor of love,” Early explained. “We’re not for profit. It’s more for community building.”

Situated between Market Street and the Patricia’s Green park, and just down from the Biergarten, the Art Works gets plenty of foot traffic, but the incessant automobile noise tends to drown out the jazz effort, and it takes extra effort to get people to stop and enter through the cyclone gate.

The reception opened at 2 p.m., and just beforehand, artist Todd Young went along the sidewalk with colored chalk and wrote, “Come into the garden and see some art … and hear some music.”

If that didn’t work, Young had a bubble machine going at the corner where he stood in a top hat made of Amazon boxes and manned an art cart. There he sold rocks that he had painted in black-light colors for $1 each.

“I’ve got flowers,” he called out to passersby, holding up a rock painted as a daisy. “So if you love someone you can throw a flower at them.”

Darla, Early’s Chihuahua/terrier mix with her own Instagram account, sat at the door as greeter. There was room inside for five or 10 guests, but the gallery also has the advantage of being small enough to visit without actually climbing in. Its exterior walls are perfect for murals to enhance the landscape.

“It’s very cool that you can stand on the outside of the container and see in,” said Jacqui Naylor, who had stopped by. “I love the idea of it on this strip of land that has been changing for all these years and the community spirit that it brings.”

Up the dirt path, Unger was in his element, wearing his Lester Young-style porkpie hat and playing his tenor sax to the keyboards of Sam Peoples. Unger was as cool as his art inside, but he also was not above a subtle sales pitch.

“After every song or two I mention the artwork,” he said, “and tell people to come on inside and see it.”

Reach Sam Whiting:swhiting@sfchronicle.com