It’s the season of melon-cholia: so many melons, so hard to pick a good one.

I’m pretty good at picking produce, but I got a reminder of just how tricky melons can be. At a farmer’s market recently, one of my favorite farmers was handing out samples from a watermelon as close to perfection as I’ve tasted.

Deep crimson, face-dripping juicy, with a flavor that screamed out for the slightest sprinkle from the salt shaker. This farmer specializes in melons grown from heirloom seeds, so I had him pick one for me.

I took it home, sliced it open and said, “What the heck is this?” It was white and barely pink inside, with a flavor my bemused husband described as “like a drawing of a watermelon.”

Normally, I wouldn’t complain, but I know this farmer. So the next week, I whispered in his ear. He looked shocked, pawed around and picked another. I took it home, cut it open ... and found the same thing.

On the third try, I finally got a beauty of a melon. But I felt guilty about the waste. And I wondered: These were heirloom melons. They were all dark green. They all felt heavy and juicy. How could you possibly pick?

Russ Parsons was sympathetic when I called with my tale of woe.

“Melons are the toughest,” he agreed. Parsons is a food writer for the Los Angeles Times, and an expert on produce. He wrote a book in 2008, “How to Pick a Peach,” and he wrote a column himself last week on melon travails.

Usually, I’m good at cantaloupes. I know to gently press the flower end for just a little give, and I know to smell it for sweetness. But watermelons? We thump, we study stems, we check the couche, or field spot, where a truly ripe watermelon sat in the dirt. But sometimes, you just can’t tell.

Parsons divides melons into two families: Net-skinned, like cantaloupes, and smooth-skinned, like watermelons and honeydews. It’s more than a cosmetic difference.

“Smooth melons, it’s a different botanical family. All the tips (for picking them) are different.”

And what really makes it tough is that netted melons will ripen after picking, but smooth melons won’t.

Netted melons do smell sweet when they’re ripe. Smooth melons? Their Latin name means “inodorous” – no smell.

With honeydews, Parsons looks for underripe ones for comparison. The surface of an underripe one is slightly green, and sort of shiny-hard, “like a cue ball.” A ripe one held up next to it will have a surface that’s looks softer, almost velvety, with a color like rich cream.

And watermelons? Some people dismiss thumping, but he’s a believer. “If you thump in the middle and it sounds like a hollow-core door rather than a solid wood door, that has always worked for me.”

Oh great. Now I have to spend the summer thumping on doors. My husband is going to look really bemused.