Whether a watermelon is sweet depends the grower and Mother Nature, as well as proper storage. These tips will show you how to tell if a watermelon is ripe and ready to pick from the vine. PLUS – I’ll tell you how to store a watermelon for best flavor and nutrition.
How to Tell if a Watermelon is Ripe
Some of these tips will help you tell when a watermelon is ripe on the vine. Others apply to both picking or buying watermelons at the grocery store or farmers market.
Ripe watermelons are a little trickier to identify than muskmelons. Muskmelons slip right off the vine (i.e. come loose on their own) when ripe. Watermelons don’t fall off the vine when ripe.
#1 – Check the Field Spot on the Underside of the Watermelon
The underside of the watermelon where it touched the ground should be buttery yellow to dark yellow in color. This is called the field patch or field spot.
If the field spot as pasty white as a bald guy’s head in the middle of a Wisconsin winter, it’s an underripe or unripe watermelon.
Different growing conditions and different types of melons will produce a range of colors (inside and out). Warmer weather usually yields a darker field spot.
Sometimes you may also see sugar spots, small black spots, often near the blossom end, where sap has leaked. We don’t commonly get these in our northern garden.
#2 – Check the Sound to See if a Watermelon is Ripe
This is a classic way to pick a good watermelon. The internet is filled with descriptions of how a ripe watermelon should sound. Most say “flat” or “dull”, but I think that’s a poor description.
A ripe watermelon should have a nice, deep hollow sound, more like a drum or knocking on a door. I did a quick video (below), knocking on a melon that looks promising.
#3 – If you want a ripe watermelon, make sure it is fully grown
This is for those trying to figure out how to tell if a watermelon growing in the garden is ripe. Days to maturity will give you a rough estimate of expected watermelon ripening time.
When a watermelon is well filled out and isn’t changing in size, it’s time to looks for signs of ripeness. The rind of the melon will get darker and duller when it reaches full growth. Young melons look more shiny.
#4 – Check the Little Curling Tendril Located Where the Watermelon Stem Joins the Main Vine
This is another tip for checking ripe watermelons in the garden. Right where the stem to your melon joins the main vine, there should be a little curling tendril of vine. If the tendril is still green and springy, the melon is still growing.
If this little tendril is brown and dried, odds are your melon is as ripe as it’s going to get. Sometimes all your vines may start dying back before you’ve harvested, not just a tendril. Ready or not, your watermelons are done growing.
Also, if it’s been dry, sometimes the tendrils will dry back prematurely, so check the other signs first.
#5 – Poke Your Blossom End
Jerry, one of our readers, shares his experience:
I mostly agree with the methods mentioned in this article.
My dad grew watermelons for many years in Florida so he had the advantage of following the fruit’s development to complete ripeness. I have passed his knowledge on to many friends who confirm his method of ripeness selection.
Because so much depends on soil fertility and irrigation/rainfall sweetness is hard to determine. However, determining RIPENESS is a fairly full proof method. Thumping a melon doesn’t mean much at all regarding sugar content.
In fact, the only indicator a consumer has in the market for determining the melon’s RIPENESS is by pressing on the blossom end of the water melon to see how much “give” it has. The blossom end is opposite the stem end.
If it is ripe there will be some give when pressed with the thumb. If it’s not ripe it will be hard as a rock. A watermelon that’s TOO ripe it will give little resistance, and likely be “mealy” inside.
It’s always worked for me, for what it’s worth.
How to Store Watermelon
Melons like to be stored warm. Storing watermelons at room temperature also makes them more nutritious.
From the article “Watermelon Fruit nutritional value health benefit” by Ray Sahelian, M.D.:
Watermelons stored at room temperature deliver more nutrients than refrigerated or freshly picked melons.
Researchers tested several popular varieties of watermelon stored for 14 days at 70 °F, 55 °F and 41 °F. Whole watermelons stored at 70 °F, which is about room temperature in air conditioned buildings, had substantially more nutrients.
Compared with freshly picked fruit, watermelon stored at 70 °F gained up to 40 percent more lycopene and 50 percent to 139 percent extra beta-carotene, which the body converts to vitamin A. Watermelons continue to produce these nutrients after they are picked and that chilling slows this process.
The usual shelf life for watermelons is 14 to 21 days at 13 °C (55 °F) after harvest. At refrigerated temperatures, such as 41 °F, watermelon starts to decay and develop lesions after a week.
Do not store your melon in the refrigerator until it’s cut (or chill only briefly right before serving). Once it’s cut and refrigerated, eat it up ASAP.
When we do our final melon harvest in fall when frost threatens, I aim to pick them after several dry days. Picking a watermelon right after heavy rain or in wet conditions will reduce storage life.
I store our watermelons in open cardboard boxes in the basement, which has a temperature of around 70°F. We make sure there’s good air flow around the melons. The boxes stay open so we can easily visually inspect them for any signs of spoilage.
As our garden soil has improved, so has the storage life of our melons. We are now able to store home grown watermelons for months after harvest, not weeks.
Tips from “An Experienced Farmer” on How to Pick a Good Watermelon
There are “tips from an experienced farmer” circulating online about how to pick a good watermelon.
Some of these are valid, some of them are flat out wrong. I suspect that the information was made up as a way to sell round watermelons with marks on them. I’ll review these “tips” (listed in italics) to let you know what’s right and what’s wrong.
#1 – Look for the Field Spot
The yellow spot, known as the field spot, is the place where the watermelon rested on the ground. Ripe watermelons always have creamy yellow or even orange-yellow spots, not white. – CORRECT, as noted above
#2 – Look for ‘webbing’
These weblike brown spots on the watermelon mean that bees touched the pollinating parts of the flower many times. The more pollination, the sweeter the fruit is. – WRONG
As noted by Texas A&M Agrilife Extension Plant Disease Handbook:
“Cracks, scarring, and pitting can be caused by mechanical damage when vegetables are young, Insects can also cause such injury. Animals, such as wild hogs and racoons, can cause more substantial damage.”
In my experience, heavy exterior scarring often leads to tough or woody areas inside the fruit. (Mild scarring is not a problem.) More scars does not mean a sweeter watermelon.
#3 – ‘Boy’ and ‘Girl’ Watermelons
Many people do not know that farmers differentiate watermelons by gender. For example, ’boys’ are bigger, have an elongated shape, and a watery taste. The ’girls’ have a rounded shape and are very sweet. – WRONG
All watermelons come from female flowers, which have a small swelling at the base of the flower. There are no male watermelons. The shape of the watermelon is determined by the variety of watermelon.
A round watermelon is not necessarily a better watermelon. Both melons pictured below were good, but the so-called “male watermelon” (the longer one) was sweeter then the round one.
#4 – Pay Attention to the Size
It is better to choose neither the largest nor the smallest watermelon. Select an average sized fruit. And note, please: large or small, the watermelon should feel heavy for its size. – SIZE DOESN’T MATTER
If you’re shopping at the grocery store, and you’ll typically find that the melons are all similar in size. In the garden, you want to look for large fruit that are fully grown.
If you start lifting watermelons, I bet in most cases you’ll find that their weights are similar as well. Grocery stores like uniform produce.
#5 – Inspect the Tail
A dried tail indicates that the watermelon is ripe. However, if the tail is green, it probably means that the watermelon was picked too soon and will not be ripe. – MAYBE
As noted above, it’s the tendril next to the watermelon on the vine that acts as a ripeness indicator. The vine itself may or may not indicate ripeness.
A brown stem in a grocery store could mean the melon sat around after harvest. It could also mean that the plant was dying when the watermelon was harvested. You have no way to know for sure.
Good Watermelons for Northern Growers
Growing watermelons with a short growing season can be a challenge, but with extra care we manage a good harvest. Some of our favorite watermelon varieties include:
- Blacktail Mountain
- Yellow Petite
- Crimson Sweet
Even though Orangeglo and Yellow Petite don’t get red, the same rules still apply for determining if they are ripe. Sugar Babies are another popular variety for home gardeners, but we prefer the flavor of these varieties.
Here’s one of my favorite watermelon photos from a few years ago.
Unlike some fruits, watermelons do not continue to ripen once they are off the vine. Choose carefully, and store watermelons the right way to keep them flavorful.
Can you tell if a watermelon is ripe by smell? Nope. Uncut watermelons are less fragrant than muskmelons, because they don’t have that open end where the vine was formerly attached.
You will never find me sniff testing watermelons in the grocery store, but you may find me sniffing cantaloupes.
Thank you for reading! We love your shares and comments. Did I miss any tips that you use to pick a good watermelon? Leave a comment and share your thoughts.
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Originally posted in 2014, last updated in 2022.