It’s a sign of the times when a Pacific Northwest farm stand with signs screaming. “Local Produce!” features bananas, mangoes and oranges.

You have your suspicions, (how powerful are greenhouses, anyway?) but what to do?

www.grist.org has an etiquette lesson for those who may struggle with how to politely ask the right questions at the farmer’s market.

“In essence what we are asking is, ‘Are you poisoning me?’ And while food questions are not quite as loaded as ‘Are you still beating your wife?’ the mere inference of wrongdoing might make a farmer a bit defensive,” writes Grist contributor Lou Bendrick.

There are certain things that, in our society, simply don’t seem polite to question. I’ll never forget being nudged (and increasingly kicked) by a friend when I questioned someone manning a global relief agency’s booth at a fair.

“100 percent goes to the child? 100 percent? Then who pays you?” I grilled.

The poor employee was flustered and had no idea how to answer my question.

I could have been more tactful.

On the other hand, should organizations claiming to do good work (selling local produce, saving children in Africa, importing hand-made goods from the women of South America) get a pass because they’re trying? When should we question the “A” for effort?

Bendrick consulted with etiquette scion Anna Post, who says that people who observe good practices are usually excited to talk about it.

But if you ask, prepare to stick around a while.

Steve Sando, founder of Rancho Gordo, warns against the expectation of a short answer when asking if a certain product is “organic.”

“I would love to talk about it, but people want a yes or no answer,” he said. “It’s not as simple as a yes or no. Do you mean certified? Do you mean the way we grow it?”

That’s all the more reason to buy local food from growers you know. That sounds like tall order, but it doesn’t have to be. Not every farmer publicly shares family stories and recipes, but those who know their produce have them.

Just ask.