Garden Guide: How to pick the sweetest watermelon

Watermelon is a delicious summer treat, but some are sweeter than others. Here are a few tips to make sure you pick the best ones from the store or fresh off the vine.

Alex Calamia

Aug 3, 2023, 8:30 AM

Updated 437 days ago

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Watermelon is a fun summer treat and an exciting plant to grow in the garden. They are ready to eat just in time for the hottest days of the year, but it's disappointing to bite into one that has no flavor. These fruits don't ripen after they are picked off the vine so there is no easy way to fix a bad melon. Fortunately, it's easy to identify which watermelons are ripe, and which are duds with these tips below.

How to pick a sweet watermelon

  • The Tap Test: Watermelons are not a musical instrument, but picking a ripe watermelon will be music to your ears. Pick up the fruit and give it a light tap. If it gives back a hollow sound, it usually means its grown to full size and is sweet.
  • Is it heavy for its size? If the watermelon feels heavier for its size, then it’s an indication that there is plenty of sweet juice inside. Small watermelon can be just as sweet as large watermelon.
  • Check underneath: If there’s a yellowish, creamy underside where the fruit was laying in the dirt, it’s usually ripe.
There's a foolproof way to pick watermelons fresh off the vine. If you’re growing your own watermelons, you’ve probably noticed the squiggly tendrils the plant uses to secure the fine into place. The tendril growing closest to your fruit will turn brown and be totally when the fruit is ripe. Don't pick watermelons off the vine until the closest tendril dries up.

How to grow your own watermelon

Watermelons are a huge fruit, so it's no surprise that the vines they grow on are massive too. They demand full sun, well-draining soil, lots of organic fertilizer, and plenty of water. Otherwise, these plants are very simple to grow. I always prefer to grow watermelon from a pack of seeds. Watermelon plants grown from seed often outpace the seedlings bought at the store because they don't like their roots disturbed. It's also easier to find fun watermelon varieties from seed packets.
After watermelon seeds sprout, they take 30 days to produce their first male flowers (those contain pollen) and another 30 days to produce female flowers. If the plant is healthy and happy, the female flowers will swell and produce fruit that take about 2 months to ripen. The process takes about 4 months from seed to ripe fruit, and you can expect 1-4 melons from a single plant which can reach 20 feet long.
Most watermelon plants get too big for the average garden, but small gardens can get in on the fun of growing watermelon too! Compact watermelon varieties have vines that reach only 5 feet long. The fruit from varieties like "Sugar Baby" and "Yellow Doll" are usually smaller than a volleyball and do great in a large container. Compact watermelon varieties also ripen much sooner than their larger counterparts. Gardeners can expect ripe fruit on vines that are only 3 months old - that's a month earlier than larger varieties.
I start my watermelon seeds in late April or early May. they grow very slowly in early spring, but quickly pick up the pace when temperatures are consistently warm. This year I'm growing all of my watermelon in containers and so far, it's going well. I selected the largest containers I could find and placed just one watermelon plant in each. The root system on these plants is massive so as the plants get older, you'll notice they require more water and fertilizer to be happy. Growing fruit requires a lot of energy. If fruit fails to form, it is probably from too little or too much watering. If plants receive water too quickly the fruits can crack. Compact varieties are less prone to these problems because they don't take as long to ripen.