MILE MARKERS ON THE ROAD TO DETROIT: ‘Hostile architecture’ vs. beautification: Sidewalk planters are flashpoint in homelessness crisis.

Outside the City Hope Cafe in San Francisco stand two new large, gleaming metal tubs filled with hundreds of pounds of soil. Installed on the sidewalk last week, the planters will add a touch of greenery to the cafe that serves homeless people for free in the gritty Tenderloin neighborhood.

But the cafe’s operator, the Rev. Paul Trudeau, acknowledges that their purpose is also functional — a tactic that a recent Chronicle block-by-block survey showed is often resorted to by San Francisco residents and businesses to deter encampments on the sidewalks around them after the city proved unable to provide long-term solutions.

At City Hope, an encampment where screaming matches and fights frequently broke out, including one where a person was arrested for beating another with a hammer, has been blocking the front of the cafe for months, Trudeau said — and despite near-daily calls to 911, the campers repeatedly returned.

So he put in the planters.

“We love our community, and we love the people who walk through our doors,” Trudeau said. “But you can’t get in our doors if you can’t get down the sidewalks.”

As San Francisco continues to grapple with its homelessness crisis, sidewalk planters have proliferated, becoming the latest flash point in the debate over what to do about the thousands of people who live on the city’s streets.

Flashback: “Despite its spending more money per capita on homelessness than any comparable city, [San Francisco’s] homeless problem is worse than any comparable city’s,” SF Weekly noted 15 years ago, stumbling into the Fox Butterfield effect.