Watermelon Guessing Game: How to Tell if a Watermelon is Ripe

There's nothing worse than watching a watermelon grow to size for weeks on the vine and then cracking it open only to find it's not quite edible. Last year I played and lost the watermelon harvest guessing game so many times I almost decided not to grow them this year, but I didn't want to give up after just one season. I put them in my summer garden again, and I'm glad I did!

New Queen yellow watermelon

Watermelons are notoriously difficult to harvest, and sit at peak ripeness for only a day or two. They do not continue to ripen once cut from the vine, so the ideal harvest window is very small. Researching this online, I've found lists of more than ten factors to consider when trying to figure out whether a watermelon is ready. Some advice is ridiculously unclear, as in the following from gardenweb: "Thump it. If the watermelon sounds hollow (if you hear a dull thump/thud), the melon is usually ripe. The unripe melon will have a tighter, metallic ringing or hollow sound." Huh?

Looking ready to pick, but is it? (No!)

Having learned through trial and error last summer, I now look at just three factors as I attempt to avoid splitting open a pale, under-ripe melon:

• weight
• tendril
• leaf

First, I look for a watermelon that is heavy for its size. Watermelons are made mostly of water (duh!) and water is heavy. I evaluated this watermelon for weight before cutting it, and then used the scale to find out it weighed 5.5 pounds, which is in the correct range for this variety.

This one weighed in at about 5 1/2 pounds

The second factor I take into account is the status of the curly tendril closest to the stem of the developing fruit. In the first picture below, taken two weeks ago, the tendril is still green, a sign the melon isn't ripe. In the second picture, the dry tendril is an indication the melon is ripe.

Green, flexible tendril indicates an unripe melon

Brown, dry tendril indicates a ripe melon

The last thing I look at is the tiny leaf closest to the stem of the developing melon, called a "spoon" leaf for its shape. A green leaf is a sign the watermelon is still developing; a dry leaf is an indication the melon is ripe. Sometimes you might not find a leaf at all, which probably means it has dried and fallen off the stem.

"Spoon leaf" is still green and attached to the plant

There are three factors I don't pay attention to in this guessing game. One is sound, something experienced farmers supposedly use to determine ripeness: if the watermelon makes a tinny, metallic sound upon tapping it in the morning, it's not ready, but if it makes a dull, thumping sound, it's ready. I tried this multiple times last summer and when I thought I could tell the difference, I was wrong.

I also found size not to be a trustworthy indicator of harvest readiness. Last year we grew Sugar Baby melons and those were supposed to be small, like these New Queens. One grew to almost twice the expected size, so I thought for sure it was ripe--nope.

Finally, I disregard the color of the underside of the melon. Everything I read says a ripe watermelon has a yellow underside, and that an unripe one has a pale green or white underside. My experience has been almost the opposite. The first picture below shows my watermelon two weeks ago with a prominently yellow underside. The second picture was taken at harvest, by which time the color had paled.

Two weeks ago, yellow underside indicates ripening

At harvest, melon has a pale yellow underside

I'm happy to report that I did in fact win the guessing game with the watermelon pictured in this post. I cut it from the vine (no pulling, the way you harvest other types of melons), split it open and was delighted at the bright yellow color, rich flavor, and crisp texture. I probably could have cut it a day or two earlier, but it's hard to tell. It tasted great to me.

Half a New Queen watermelon

Bowl of sweet melon slices

I leave a little extra on the rind for the chickens

Score so far: unripe/overripe melons: 0, me: 1. Have you ever tried growing watermelons in your garden? Got any secrets for harvesting at peak flavor?