Carol O'Meara, Colorado State University Extension

Carol O’Meara, Colorado State University Extension

BOULDER COUNTY – Early August brings sweet treats to our stores as wonderful Colorado melons roll in.  I follow Rocky Ford Growers Association on Facebook, so when they announced that melons were here, I rushed over to the grocers.

Approaching the stacked cantaloupes, I looked over the melons for the perfect one to take home. As I lifted and tested the rind a man came up next to me and said “I hate to ask, but how can you tell when they’re ripe?”  I’m not often asked how to pick produce while at the store, so was happy to answer.

Slowly I turned toward him. With a smile I grasped a cantaloupe, showing him how the netting should be raised and distinct from the rind while the skin underneath is a tan-yellow.  Flipping the melon to the blossom end, opposite the indentation from where the stem attached, I showed him how it should have a slight give when pressure is applied.  Finally, I spoke of the aroma a ripe muskmelon has, handing him the near-perfect melon.

“See for yourself; you’ll get the hang of it,” I said, turning back to shopping for my own cantaloupe. He took to the task seriously, leaning over and setting pressure to the blossom end with determination. As I glanced back, I realized he was pumping that melon like he was applying CPR, so I gentled his effort and avoid crushing the poor thing.

Gardeners have an advantage when growing cantaloupes because the fruit tells us when it’s ripe. We look for the same signals – color, raised netting and aroma – but also slip stage, which is when the muskmelon separates from the vine. Once the color of the fruit changes, check the where the stem attaches to the melon for separation. When it’s separated two-thirds of the way around the stem, the melon can be harvested.

Walking further into the store I stopped at the sight of a shopper slapping watermelons. At the bin for smaller, personal-sized watermelons, her palm open, fingers splayed, she methodically smacked those mini melons like it was a whack-a-mole game at the arcade. Perhaps she was seeing if they were firm, or was listening to the sound; I have no idea what that shopper was doing, but clearly she was enjoying herself.

Picking a watermelon at the store is a challenge, and I’ve heard of thumping the melon to listen for the dull thud of ripeness.  Typically it’s a knock from the knuckles while holding the melon up where you can hear it. Unripe melons sound hollow while ripe ones have a meaty thud, the experts say.

I’ve not been able to hear what they’re talking about so I go with two other indicators: belly color and toughness. Where the watermelon sits on the ground, the skin will turn yellow or cream color when ripe; if it’s still a clear white or even green, move on to another melon. Also, the ground spot toughens a bit, so test it gently with a fingernail to see if it dents easily. If it doesn’t dent from your fingernail, the melon is ripe.

Gardeners growing watermelon or honeydew can rely on simple math: count the days from when the female flower ‘sets’, starting to swell after pollination. 40 days from setting, the melon is ripe.  Watermelons also give gardeners a clue when the curly tendril closest to the melon on the vine dries.  That, plus belly color, should tell you when it’s time to harvest.  Honeydew should be a creamy yellow color; wait to pick them until they do or the green melon won’t ripen off the vine.

Try these gardener’s tricks for choosing melons at the store, instead of slapping, thwacking, crushing or otherwise abusing the fruit.

By Carol O’Meara, Colorado State University Extension. Colorado State University Extension, together with Boulder County Parks and Open Space, provides unbiased, research-based information about consumer and family issues, horticulture, natural resources, agriculture and 4-H youth development. For more information contact Extension at the Boulder County Fairgrounds, 9595 Nelson Rd., Box B, Longmont, 303.678.6238, e-mail [email protected] or visit