This post contains affiliate links. As an Amazon Associate I earn from qualifying purchases. If you click a link and make a purchase, I may receive a small commission at no extra cost to you.
To grow a big watermelon, you need to focus on three critical things: the right variety, plenty of space, and consistent care from seed to harvest.
Growing watermelon isn’t complicated when you understand what the plant truly needs.
If you’ve ever wondered how to grow a big watermelon that tips the scales, the answer lies in proper planning and patience.
In this post, we’ll walk through exactly how to grow a big watermelon by choosing the right seeds, preparing your soil, watering correctly, and timing your harvest.
Let’s dig in.
How to Grow a Big Watermelon: Start With the Right Variety
The first step in learning how to grow a big watermelon is choosing a variety known for size.
Not all watermelons are created equal, and some varieties are bred specifically for giant fruit.
Here are the best options if your goal is a massive melon:
1. Carolina Cross
Carolina Cross is the gold standard when you want to grow a big watermelon.
This variety regularly produces fruits that weigh over 200 pounds under ideal conditions.
It needs a long growing season of about 90 to 100 days, so start early if you live in a cooler climate.
2. Black Diamond
Black Diamond is another excellent choice for how to grow a big watermelon.
These dark green melons can reach 75 pounds or more with proper care.
They’re known for their sweet, red flesh and thick rind, which helps them hold up during the long ripening process.
3. Jubilee
Jubilee watermelons are a popular pick for growers who want to grow a big watermelon without waiting forever.
They typically mature in about 85 days and produce oblong fruits weighing 40 to 60 pounds.
Their reliable size and sweet flavor make them a favorite for home gardeners.
How to Grow a Big Watermelon: Prepare the Soil and Space
Once you’ve picked your variety, the next key to how to grow a big watermelon is giving the roots room to stretch.
Watermelons are heavy feeders and thirsty plants, so the soil and spacing matter more than you might think.
1. Test and Amend Your Soil
Watermelons thrive in loose, well-draining soil with a pH between 6.0 and 6.8.
Before planting, mix in plenty of compost or aged manure to feed the vines.
Adding organic matter also helps the soil hold moisture, which is essential when you grow a big watermelon.
2. Give Each Plant Plenty of Room
If you want to grow a big watermelon, don’t crowd your plants.
Space them at least 6 feet apart in rows that are 8 to 10 feet apart.
Crowded vines compete for water and nutrients, and that competition leads to smaller fruit.
3. Use Black Plastic Mulch
Black plastic mulch warms the soil and keeps moisture levels steady.
Warmer soil means faster growth, and steady moisture means fewer cracks and better fruit development.
Both of these factors help you grow a big watermelon successfully.
How to Grow a Big Watermelon: Water, Feed, and Pollinate
Consistent watering and feeding are where most growers either succeed or fall short when learning how to grow a big watermelon.
Watermelons are about 92% water, so what you give them directly affects their size.
1. Water Deeply and Regularly
Give your plants 1 to 2 inches of water per week, ideally through drip irrigation.
Deep watering encourages strong roots that can support a massive melon.
Reduce watering slightly as the fruit ripens to concentrate the sugars and prevent bland, watery flesh.
2. Feed With the Right Nutrients
Start with a nitrogen-rich fertilizer early to encourage leafy growth.
Once flowers appear, switch to a formula higher in phosphorus and potassium.
This shift supports fruit development, which is crucial when your goal is to grow a big watermelon.
3. Hand-Pollinate for Better Fruit Set
Bees usually handle pollination, but you can help if your vines aren’t setting fruit.
Pick a male flower, remove the petals, and dab its pollen onto the center of a female flower.
Better pollination means more seeds, and more seeds mean a bigger, fuller watermelon.
4. Prune for Quality, Not Quantity
Limit each vine to one or two fruits if you want to grow a big watermelon.
Removing extra melons lets the plant pour all its energy into the remaining fruit.
This single tip can be the difference between a decent melon and a prize-winner.
How to Grow a Big Watermelon: Harvest at the Right Time
Knowing when to pick is just as important as knowing how to grow a big watermelon.
Pick too early and the flesh won’t be sweet, but leave it too long and it turns mealy.
1. Watch the Tendril
The curly tendril closest to the fruit turns brown and dries up when the melon is ripe.
This is one of the most reliable signs that your watermelon is ready.
2. Check the Field Spot
The spot where the melon rested on the ground should be creamy yellow, not white or green.
A rich yellow field spot tells you the fruit ripened fully on the vine.
3. Listen for the Thump
A ripe watermelon gives a deep, hollow sound when you thump it.
A dull thud usually means it’s overripe, while a sharp ping means it’s still underripe.
So, How to Grow a Big Watermelon?
To grow a big watermelon, start with a giant variety like Carolina Cross, give the vines plenty of space, water deeply, feed wisely, and harvest at the perfect moment.
Learning how to grow a big watermelon takes patience, but the payoff is worth every bit of effort.
Follow these steps and you’ll know exactly how to grow a big watermelon that makes your neighbors jealous.
Now go plant those seeds and get ready for a giant harvest.