Here's help for picking the best melons, tomatoes, peaches and other late-summer delights.

It wouldn’t be summer without wonderful produce at a farmer’s market. Any nutritionist would go wild. So do lots of gardeners.

There is nothing like biting into a ripe peach over the kitchen sink and have the taste buds assailed by sweet juice. Or the sensation as the juice trickles down the chin. A ripe watermelon brings back memories of picnics and seed-spitting contests. Sweet corn, quickly cooked for less than three minutes in boiling water so the butter melts quickly when the ear is rolled, pops with sugar and flavors as each kernel is warmed.

On the other hand, there’s nothing like biting into something and discovering it’s not ripe.

There’s an art to selecting fresh produce.

Watermelons are frustrating. You just can’t tell how ripe the melon is until you cut into it. If it’s ripe, great. If it needed a couple more days on the vine, you’re out of luck.

The ol’ thump trick is about the best method if the watermelon is already picked. Give the watermelon a thwack on the rind with your fingertips. If it sounds hollow, it’s probably ripe. If the sound is dull and flat, the melon is probably immature. It’s not a perfect system, but it’s the best we have.

Watermelons won’t smell from the stem end, so placing them under your nostrils won’t tell you much.

Some will argue that seeded watermelons are sweeter than seedless. It’s a tossup, but if you can go either way, go with the seeded forms. Seedless forms aren’t totally seedless, but have the white seeds that are soft and easily swallowed. Those immature seeds are worthless in spitting contests.

The shape of the watermelon doesn’t matter much, either. The size is more of a storage issue. Why get a monster melon if there is no room in the refrigerator or if you are the only one eating it?

Ripe watermelons should be uniformly green, though many are striped. They should have a dull surface color.

Most cantaloupes and honeydew melons will have an obvious sweet melon smell at the stem end. Pick one up and put it next to your nose. If it smells like a cantaloupe, it’s probably ripe. If you don’t smell anything, and you know your nose is working, move on.

Additionally, the rind on cantaloupes will be slightly soft. A cantaloupe won’t have much green in the rind, though there might be hint in the undercolor or around the stem end or where it was lying on the ground.

Thump any cantaloupe and it probably will sound hollow — there’s a cavity from day one. That’s probably the least-reliable test.

Watermelon and cantaloupes should feel heavy. If they feel light, they probably aren’t ripe.

Peaches may or may not have much of an aroma, but it’s easier to tell if they are ripe.

A green peach is as worthwhile as a green cherry. A pink, orange, yellow or golden color is a good indicator of ripeness.

Peaches will also have a slight give when ripe. Unlike melons, which will not ripen on the kitchen counter but only soften, a peach will continue to mature. So choose some that aren’t fully ripe if you want to enjoy them throughout the week.

Some like the doughnut peaches. Some like the white flesh. Some opt for cling peaches, which means the pit is attached firmly to the flesh. Freestones, with loose pits, are the most common.

Size does matter, as the pits are roughly the same size. So, a larger fruit should mean more flesh to dribble on the floor. They do ripen more slowly. And you don’t get as many in a box, peck or bushel.

Separate peaches from each other if they aren’t fully ripe. Like an apple, one rotten peach will spoil the bunch. Place them on layers of newspaper, separating the peaches a few inches from each other. Check the fruit daily, turning them over and giving them a light squeeze. When they are ripe, store them in the refrigerator.

Treat tomatoes just like peaches. They should feel firm and heavy. If not fully ripe, they will mature on the counter.

There’s a perpetual argument about storing tomatoes in the refrigerator. It will slow down the ripening and can concentrate the sugars, but many believe the tomato flavor is destroyed.

Finally, the only way to determine sweet corn’s maturity is pulling back the husks. You should find plump kernels without any hint of indentations, which means the corn is past prime.

The husks keep the corn fresher longer, so leave them on. You should be able to run your hand carefully over the ear and feel the kernels underneath, sort of like a miniature cobblestone highway. If you feel something squishy and moving at the tip, that’s probably an insect. It’s protein.

David Robson is a specialist with University of Illinois Extension. For more gardening information go to www.extension.uiuc.edu/mg.