Growing a giant watermelon is the ultimate goal for many backyard gardeners. It’s a fun challenge that yields impressive results. This guide will walk you through every step needed to grow a champion-sized melon in your own garden. You’ll learn about the right varieties, soil preparation, and the special care these giants need. With some patience and attention to detail, you can achieve a harvest that will amaze your friends and neighbors.
The journey starts long before you plant a single seed. Success depends on planning and creating the perfect environment for your watermelon vine to thrive.
How to Grow a Giant Watermelon
This process is more than just regular gardening. It’s a focused project. Think of it as training an athlete; every detail from nutrition to training matters for peak performance.
Step 1: Choosing the Right Giant Variety
You cannot grow a 100-pound watermelon from a small picnic variety seed. Selecting genetics bred for size is your first and most critical step. Here are the top champions:
* Carolina Cross: This is the world record holder. Fruits can easily reach 150-200 pounds under ideal conditions. They have a long growing season (about 90 days).
* Black Diamond: A classic, heirloom variety known for huge, oblong fruits with very dark green rinds. They are reliable and can produce 50-100 pound melons.
* Jubilee: Another popular giant, often producing 40-50 pound melons consistently. It’s a good choice if you have a slightly shorter season.
* Mountain Hoosier: A productive variety that yeilds multiple large melons per vine, often in the 30-50 pound range.
Always buy seeds from a reputable supplier. Make sure your local growing season is long enough for your chosen variety to mature.
Step 2: Preparing the Perfect “Melon Bed”
Giant watermelons are heavy feeders. They need deeply prepared, nutrient-rich soil to support their massive growth. Here’s how to build their bed:
1. Pick a Sunny Spot: Choose a location that gets a minimum of 8 hours of direct, unfiltered sunlight daily. More sun is better.
2. Create a Hill or Mound: Form a raised mound about 12 inches high and 3-4 feet wide. This improves drainage and warms the soil faster.
3. Amend the Soil Deeply: Don’t just scratch the surface. Dig down at least 2 feet in your mound area. Mix in huge amounts of compost and well-aged manure. This creates a loose, fluffy soil that roots can penetrate easily.
4. Test and Adjust pH: Watermelons prefer a soil pH between 6.0 and 6.8. A simple test kit can tell you if you need to add lime (to raise pH) or sulfur (to lower it).
5. Add Balanced Nutrition: Work in a balanced, slow-release organic fertilizer into the entire mound before planting. This gives seedlings a strong start.
Step 3: Planting for Success
Timing is everything. Watermelons need warm soil and no threat of frost.
* When to Plant: Wait until soil temperatures are consistently above 70°F. This is usually 2-3 weeks after your last frost date.
* How to Plant: Sow 4-6 seeds per mound, about 1 inch deep. Once seedlings have two sets of true leaves, thin to the 2 strongest plants per mound. Space mounds 6-8 feet apart for giants.
* Consider Starting Indoors: In shorter-season areas, start seeds in peat pots 3-4 weeks before transplanting. Be very careful not to disturb the roots when you plant the entire pot.
Protecting Young Plants
Use floating row covers to protect seedlings from cool nights and insect pests. Remember to remove them once flowers appear so bees can pollinate.
Step 4: Strategic Watering and Feeding
Consistency is the key word here. Inconsistent care leads to problems like blossom end rot or split fruit.
* Watering Deeply: Watermelons need 1-2 inches of water per week. Water at the base of the plant, not the leaves, to prevent disease. Use a soaker hose for best results. The goal is deep, infrequent watering that encourages strong roots.
* The Critical Feeding Schedule:
* At Planting: Balanced fertilizer in the mound.
* Vine Growth: When vines begin to “run” (about 12 inches long), side-dress with a high-nitrogen fertilizer to support lush growth.
* Flowering & Fruiting: Switch to a fertilizer higher in phosphorus and potassium (like a 5-10-10) when flowers and small fruits appear. This supports bloom set and fruit development.
Step 5: Pruning and Selecting Your Champion
This is where you direct all the plant’s energy into one or two fruits. You cannot let the vine produce 10 melons and expect giants.
1. Let the Vine Establish: Allow the main vine to grow and produce several female flowers (the ones with a tiny melon at the base).
2. Choose the Best Fruit: Look for the strongest, healthiest-looking female flower that appears about 4-6 feet out from the base of the plant. This fruit has a strong connection to the roots.
3. Prune Mercilessly: Once your chosen melon is about the size of a softball, remove all other competing female flowers and small fruits from the vine. You can leave one secondary fruit as a backup if you want.
4. Prune the Vine Tips: After selecting your fruit, trim the growing tips of the vine. This stops the plant from putting energy into more vine growth and forces everything into swelling the fruit.
Step 6: Supporting and Protecting the Growing Fruit
As your melon grows, it needs protection from the ground.
* Provide a Sling: Once the fruit is soccer-ball sized, create a sling from an old t-shirt, mesh bag, or stretchy fabric. Suspend it from a sturdy trellis or frame to support the weight and keep the melon off the damp soil. This prevents rot and insect damage.
* Rotate Gently: Every few days, gently rotate the melon a quarter turn. This ensures even shape and color development. Be extreamly careful not to twist or break the stem.
* Weed Carefully: Keep the area weed-free to reduce competition for water and nutrients. Hand-pull weeds near the vine to avoid damaging shallow roots.
Step 7: Knowing When to Harvest
Harvesting too early is a common mistake. Giants need every possible day to sweeten and mature.
* Check the Curly Tendril: Find the curly tendril on the stem closest to your watermelon. When it turns completely brown and dry, the melon is likely ripe.
* Look at the Ground Spot: The spot where the melon rests on the ground will change from white to a creamy yellow.
* Thump Test: A ripe watermelon will have a deep, hollow sound when thumped. This takes practice.
* Stop Watering: About a week before your planned harvest, stop watering the plant. This can concentrate the sugars in the fruit for better flavor.
Use a sharp knife or pruners to cut the stem, leaving about 2 inches attached to the fruit. Never try to pull or twist it off the vine.
FAQ: Your Giant Watermelon Questions Answered
Q: How much space do I need to grow a giant watermelon?
A: You need a minimum of 50-100 square feet per plant. The vines can easily run 15-20 feet in all directions.
Q: How long does it take to grow a giant watermelon?
A: Most giant varieties require 90-110 days from planting to harvest. Your total project time, from soil prep to harvest, is about 4 months.
Q: Can I grow giant watermelons in containers?
A: It is not recommended. The root system is too extensive and the fruit is too heavy. In-ground or in a very large, deep raised bed is best.
Q: Why is my giant watermelon not sweet?
A: The most common reasons are harvesting too early, inconsistent watering, or not enough sunlight. Letting the fruit fully ripen on the vine is crucial for flavor.
Q: What are the main pests and diseases to watch for?
A: Cucumber beetles, aphids, and squash vine borers are key pests. Powdery mildew and fusarium wilt are common diseases. Use row covers early, encourage beneficial insects, and choose disease-resistant varieties when possible.
Growing a giant watermelon is a rewarding summer project. It teaches you about plant needs, patience, and the satisfaction of a job well done. Follow these steps, keep a close eye on your plant, and you’ll be well on your way to a backyard harvest that’s truly impressive. Remember, the weight of the fruit is a testament to your care and effort throughout the season.