How do you know when a watermelon has been ripened to perfection?

Energy, hydration and sweet deliciousness... it's no wonder the humble watermelon is a favourite summer fruit the world over. But how do you select the perfect one? Picture / Supplied

A farmer’s watermelon hack has rippled through social media, as a woman revealed the man’s secret yet simple tip on how to tell if a watermelon is ripe before you take it home.

The post, which was originally uploaded to Facebook last year, has resurfaced as it was found and shared by the Delicious Recipes Facebook page.

The watermelon farmer is based in Florida. The original authors shared how they encountered the man on a trip to Florida and, once they learned of his profession, jumped at the opportunity to learn more about picking the right watermelon.

“Back in April when Kevin and I went to Florida, I met a watermelon farmer. I asked him what was the secret to finding a good watermelon,” they explained.

The farmer shared his knowledge, highlighting that the trick is to place two fingers along the skin of the fruit so you can judge the space between the light green and dark green stripes. Therefore, the watermelon should be ripe if the dark green lines are at least two fingers apart.

A watermelon farmer's secret has been revealed. You should make sure the dark green lines are two fingers apart in width. Photo / Facebook

The Facebook post explained, “He said to make sure the dark green lines are two fingers width APART.” However, the woman was not sure if the tip was legitimate.

The woman decided to take the farmer’s advice on board and tried out the hack to see for herself, and she wasn’t disappointed.

The post carried on, “When I went to food lion yesterday, I put that to the test. I bought my watermelon and cut it up. IT WAS DELICIOUS.

“Glad to know a simple way of finding a good watermelon. I thought I’d pass the info along to our friends!!” she concluded.

One of the more common ways to figure out whether a watermelon is properly ripe is by slapping it with your palm and checking if it makes a ‘hollow’ ringing sound.

Another post shared online showed off the ripe watermelon's deep and dark shades of red. Photo / Facebook

The newest repost, shared by Delicious Recipes on Facebook, has accumulated 15,000 likes and has received over 1,400 comments. It has been further shared by 5,400 people across their personal accounts.

The comments were filled with appreciation and gratitude as people online were thrilled to stumble across such a valuable tip for watermelon lovers.

“Thank you for sharing! My most favorite fruit and I always struggle picking a good one,” wrote one lady, while another confirmed that the hack was legit: “I attest this is a good way to pick a good one, my Dad taught me that and it’s true.”

Another user shared: “Thanks for the 411″ with a winking face emoji, a term that references the sharing of valuable information.

Watermelon is a popular fruit worldwide. It is packed with a variety of nutrients, such as antioxidants and Vitamins A and C. It is also made up of mostly water, making it both hydrating and great for your health.