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Does Watermelon Grow Underground

Not everyone knows how watermelon is grown. When you see a watermelon at the supermarket, you may see the dirt on the rind and assume that your watermelon grew underground. Therefore, you do your research on this: does watermelon grow underground?

No, watermelon does not grow underground. Watermelon is a trailing plant that sprawls out along the top of the soil, not beneath. 

Watermelon is not one crop that grows underground; you’ll always find watermelon growing above ground. Let’s talk more about how watermelon grows so that you can become an expert too!

Where Does Watermelon Grow

Watermelon grows in warm temperatures in the United States.

Watermelon grows anywhere in the United States when temperatures are between 65-85 degrees. 

In most places in the United States, temperatures will reach 65 or more in May and June. 

This handy table shows when the best time is to grow crops according to the USDA Hardiness Zones:

ZoneGrowing Season
1-2April – September
3-4April – October
5-6March – October
7-8March – November
9-10February – November
11-13All year

As you can see, each of the 13 Zones in the United States includes some of the warmest months of the year. 

Zones 11-13, which include most of the Southern United States, are the best places to grow watermelon because the temperature is almost always 65 degrees, so that watermelon can be grown at any time, such as in December, March, or August. 

Why Won’t Watermelon Grow Underground

Since watermelon likes warmer temperatures, it does not grow underground. 

Watermelon likes warm temperatures and heat, which means that this crop will soak up all its sunlight. 

Growing underground does not lend itself to letting the plant get all the sunlight and warmth it needs.

When growing underground, the plant will:

  • Be growing in cooler temperatures
  • Be surrounded by more moisture
  • Only have its foliage and stem exposed to the sunlight

Plus, watermelons grow to large sizes, so you must dig up your entire garden to get a single watermelon out! 

How Does Watermelon Grow

Since we now know that watermelon does not grow underground, let’s talk about how watermelon grows above ground. 


The first step to watermelon – and any plant – is to plant the seed.

Again, watermelon likes warm temperatures, so you must wait until the soil is 65 degrees or above to plant your watermelon seeds.

Germination continues as your seed grows a stem and roots. Eventually, your plant will break the surface of the soil, and you will see the first few leaves begin to grow!


A watermelon plant reaches the vining stage when it begins to vine. 

The vine will begin to grow and trail across the ground until it reaches almost 12 feet. As you can imagine, watermelon plants need a large amount of space to grow if you have over 10 feet of a vine trailing across the garden.

Leaves will also continue to grow bigger and bigger as the stem matures.

All this time, your plant’s vine is above the ground; it does not travel beneath the surface of the soil again. 


Once the stem is mature, your watermelon is ready to flower.

You’ll see male flowers first and then female flowers. You’ll only see these flowers for a day or two – so consider yourself lucky if you manage to spot them! Local pollinators must work quickly to pollinate the flowers so your watermelon can grow. 


It’s the female flower that will begin to grow the fruit. 

The watermelon begins as tiny balls that will grow to mature watermelon over the span of about a month. Again, the watermelon fruit is above the ground this entire time. 

You’ll know that your watermelon is ready to pick when:

  • The tendrils begin to turn brown
  • The spot your watermelon lays on begins to turn yellow
  • Your watermelon will sound hollow when you knock your hand against it 

Viola! You have fully grown ripe watermelon. 

Watermelons And Vertical Growth Patterns

Watermelon can even be grown in the opposite direction of the ground – upward! 

It is possible to grow watermelon on a vertical structure, yet another way to show that it cannot be grown underground. 

The process of growing vertical watermelon is similar to that of growing watermelon in a regular garden. Still, you will need to be more strategic once your watermelon begins to grow. After all, some varieties of watermelon can reach up to 40 pounds! A stem can’t hold that weight.

Watermelon plants are natural climbers, so your watermelon will know what to do if you sew your watermelon seeds near a sturdy, deep trellis structure.

Once your watermelons begin to grow, you will need to support your watermelons in some way. As long as your trellis is sturdy, you can use a piece of cloth to hold your watermelons up like a sling. 

Your cloth sling should be loose enough that your watermelons will have room to grow even larger. Otherwise, you will have to risk breaking your watermelons off the stem while changing the sling. 

Yet another reason your watermelon plants can grow above ground – and even more above ground than you might imagine! 

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