How to Grow Watermelon in North Dakota

How to grow watermelons and cantaloupes in raised beds

Choosing the Right Watermelon Variety

The first step in successful watermelon cultivation in North Dakota is selecting the appropriate variety. Different watermelon types have varying maturity periods, disease resistance, and adaptability to specific climates. It's crucial to choose varieties that are well-suited to the state's growing conditions.

When growing watermelons in North Dakota, consider the following varieties and their characteristics:

VarietyMaturity DaysSizeDisease ResistanceNotes

Sugar Baby	75-85	Small (6-10 lbs)	Anthracnose, Fusarium Wilt	Early maturing, ideal for short seasons
Crimson Sweet	90-100	Large (16-25 lbs)	Fusarium Wilt	Late maturing, needs a long, warm season
Yellow Doll	70-80	Small (5-8 lbs)	Anthracnose, Fusarium Wilt	Early maturing, unique yellow flesh
Charleston Gray	90-100	Medium (15-25 lbs)	Anthracnose, Fusarium Wilt	Late maturing, excellent flavor

Early-Maturing Varieties

Due to North Dakota's short growing season, early-maturing varieties like Sugar Baby and Yellow Doll are excellent choices. These varieties typically mature in 70-85 days, allowing for a successful harvest before the first frost. Early-maturing watermelons are smaller in size but offer a reliable yield and a sweet, refreshing taste.

Disease-Resistant Varieties

North Dakota's climate can be conducive to certain watermelon diseases, such as anthracnose and fusarium wilt. Opting for disease-resistant varieties like Sugar Baby, Yellow Doll, and Charleston Gray can help protect your crop and ensure a healthier harvest.

Preparing the Soil

Watermelons thrive in well-drained, nutrient-rich soil with a slightly acidic pH between 6.0 and 6.8. Proper soil preparation is essential for successful watermelon cultivation in North Dakota.

Incorporating organic matter, such as well-rotted compost or aged manure, can improve soil structure and provide essential nutrients. Additionally, adding a balanced fertilizer formulated for watermelons can boost plant growth and fruit production.

Soil Testing and Amendments

Before planting, it's advisable to conduct a soil test to determine the pH level and nutrient availability. Based on the test results, you can make informed decisions about the amendments needed to achieve optimal soil conditions.

If the soil is too acidic, you can raise the pH by adding agricultural lime. Conversely, if the soil is too alkaline, you can lower the pH by incorporating elemental sulfur or ammonium sulfate.

Raised Beds and Soil Warming Techniques

Watermelons thrive in warm soil temperatures, ideally between 70°F and 85°F (21°C and 29°C). In North Dakota's cooler climate, consider using raised beds or incorporating soil warming techniques, such as black plastic mulch or infrared transmitting mulch (IRT). These methods can help increase soil temperatures, promote earlier germination, and extend the growing season.

Planting and Growing

Proper planting and care are crucial for a successful watermelon crop in North Dakota. Follow these guidelines for optimal results:

• Start seeds indoors 4-6 weeks before the last expected frost date, or direct seed after the soil has warmed to at least 70°F (21°C).
• Space watermelon plants 6-8 feet (1.8-2.4 meters) apart in rows, allowing ample room for the vines to sprawl.
• Water regularly, providing 1-2 inches (2.5-5 cm) of water per week, especially during fruit development.
• Mulch around the plants to retain moisture and suppress weeds.

Planting Time and Techniques

In North Dakota, it's best to plant watermelons after the last expected frost, typically in late May or early June. You can either direct seed or transplant seedlings started indoors.

For direct seeding, sow seeds 1 inch (2.5 cm) deep and 6-8 inches (15-20 cm) apart in rows or hills. Cover the seeds with soil and water thoroughly.

If transplanting seedlings, harden them off for a week before planting to acclimate them to outdoor conditions. Gently transplant the seedlings, being careful not to disturb the roots.

Watering and Mulching

Watermelons require consistent moisture throughout their growing cycle, especially during fruit development. Aim to provide 1-2 inches (2.5-5 cm) of water per week, adjusting as needed based on rainfall and soil conditions.

Mulching around the plants with organic materials like straw or wood chips can help retain soil moisture, suppress weeds, and regulate soil temperatures.

Pest and Disease Management

Watermelons are susceptible to various pests and diseases in North Dakota, including:

• Aphids
• Cucumber beetles
• Squash bugs
• Powdery mildew
• Fusarium wilt
• Anthracnose

To prevent and control these issues, implement the following strategies:

• Practice crop rotation to disrupt pest and disease cycles.
• Use floating row covers or insect netting to protect plants from pests.
• Apply approved fungicides or insecticides if necessary, following label instructions carefully.
• Remove and destroy infected plants promptly to prevent the spread of diseases.

Harvesting and Storage

Knowing when to harvest and how to store watermelons properly is crucial for enjoying their peak flavor and extending their shelf life.

• Watermelons are typically ready to harvest 80-100 days after planting, depending on the variety.
• The underside of the watermelon should have a creamy or white spot where it rested on the ground.
• Give the watermelon a gentle tap – a dull, hollow sound indicates ripeness.
• Use a sharp knife or pruners to cut the watermelon from the vine, leaving a few inches of stem attached.

Signs of Ripeness

Several visual and physical cues can help determine when a watermelon is ripe and ready for harvesting:

• The underside of the watermelon develops a creamy or yellow spot where it rested on the ground.
• The watermelon loses its glossy appearance and takes on a dull, matte finish.
• The tendril closest to the stem turns brown and dries up.
• The watermelon develops a deep, rich color and feels heavy for its size.
• Gently tapping the watermelon produces a dull, hollow sound, indicating ripeness.

Harvesting Techniques

To harvest watermelons without damaging the fruit or vines, follow these steps:

1. Use a sharp knife or pruners to cut the watermelon from the vine, leaving 2-3 inches (5-7.5 cm) of stem attached.
2. Avoid pulling or twisting the watermelon, as this can damage the vines and compromise the remaining fruit.
3. Handle the watermelons carefully to prevent bruising or cracking the rind.
4. Gently place the harvested watermelons in a shaded area or a cool, well-ventilated space until ready for storage or consumption.

Storage and Preservation

Freshly harvested watermelons can be stored at room temperature for up to two weeks, but they will have a longer shelf life if refrigerated. Follow these tips for optimal storage and preservation:

• Store whole watermelons at 55°F to 60°F (13°C to 16°C) for up to three weeks.
• Cut watermelons can be stored in the refrigerator for up to five days, tightly wrapped or in an airtight container.
• Freeze watermelon chunks or puree for later use in smoothies, sorbets, or other recipes.
• Pickle or can watermelon rind for a tangy, refreshing treat.

Conclusion

Growing watermelons in North Dakota requires careful planning, soil preparation, and attentive care, but the reward of harvesting these sweet, juicy fruits makes it a worthwhile endeavor. By selecting the appropriate early-maturing and disease-resistant varieties, preparing the soil properly, following best planting and growing practices, and implementing effective pest and disease management strategies, you can enjoy a bountiful watermelon harvest.