Growing Watermelon

Best Planting Times for Watermelons in North Dakota

Planting MethodActivityRecommended Dates
Outdoor PlantingIndoor Seed StartingMay 1 – June 1
Transplant OutdoorsJune 15 – July 1
Greenhouse PlantingYear-roundAdjust planting based on temperature control in the greenhouse

Planting Conditions

Watermelon Planting Conditions

North Dakota’s cold climate can pose challenges for growing watermelons, especially with a short growing season in USDA Hardiness Zones 3a to 4b. Understanding optimal planting conditions is crucial to success.

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Useful Tools for Starting Watermelons Indoors

Using the right tools can enhance growing efficiency and yield.

Seeds

Choose high-quality watermelon seeds for optimal germination and plant health. Quality seeds prepare your plants for vigorous growth from the start.
Pack of Different Melon Seeds
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Planting Trays

Seedling trays provide an organized growing environment, allowing seedlings to develop strong roots before transplanting outdoors, increasing transplant success.
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Grow Lights

Grow lights are essential for effective seedling growth, especially in less sunny seasons. They provide necessary light for strong, healthy plant development.
Grow Lights Image
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Seed Starting Soil

Using high-quality seed starting soil helps facilitate quick root establishment and promotes healthy growth, giving the best start possible to your seedlings.
Seed Starting Soil Image
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Greenhouse Growing

In North Dakota, where fluctuating temperatures can hinder watermelon growth, utilizing a greenhouse provides a controlled environment for better stability. This protects against late frosts, extends the growing season, and allows for more consistent plant conditions.

Consider investing in a 10×12 FT Greenhouse priced at $1,199 for optimal growing conditions for your watermelons.
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Fertilizer

Using quality fertilizers can significantly boost watermelon health and yield in North Dakota, as it replenishes essential nutrients for vigorous plant growth.
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In North Dakota, it is advisable to plant watermelons outdoors approximately 1-2 weeks after the last spring frost date to ensure optimal conditions for growth.

Average Last Frost Dates for North Dakota’s Major Cities

CityAverage Last Frost Date
FargoMay 10
BismarckMay 8
Grand ForksMay 11
MinotMay 15
WillistonMay 20

Disclaimer: Frost dates are average estimates, and actual conditions may vary. It is recommended to monitor local forecasts and adapt planting decisions accordingly.

Other planting guides for North Dakota:

Broccoli Planting in North Dakota

Pumpkin Planting in North Dakota

Tomato Planting in North Dakota

Any questions on growing watermelons? Visit our forum to discuss: Gardening Forum.

Starting Watermelon Indoors

In North Dakota (Zone 4a), begin indoor watermelon seed starting between April 15 and May 15. This timeline ensures healthy seedlings ready for outdoor transplantation starting from late May to early June once the risk of frost has passed.

Transplanting Watermelon Seedlings

Transplant watermelon seedlings outdoors from June 1 to June 15, ensuring the soil has warmed above 70°F consistently. Space the seedlings 36-48 inches apart in rows with at least 72 inches between rows for optimal growth.

General Care and Maintenance

Watering

  • Provide consistent and deep watering to maintain evenly moist soil. North Dakota’s variable climate necessitates regular watering, especially during dry spells.
  • Water at the base of plants to avoid leaf wetness, reducing the risk of fungal diseases.

Fertilizing

  • Apply a balanced fertilizer during planting and when the first fruits start forming. Incorporating compost before planting can enhance soil fertility and structure.

Pest and Disease Management

  • Regularly monitor for common pests like aphids, squash bugs, and powdery mildew. Pest vigilance is essential due to North Dakota’s changes in climate conditions.
  • Implement organic or integrated pest management methods to protect watermelon plants from pests and diseases.

Harvesting

  • Harvest watermelons when they exhibit a uniform color and the tendril closest to the fruit turns brown. Regular harvesting promotes peak flavor and prevents over-mature fruits.

The importance of good soil

Before starting to grow it is important to take a step back and find the condition of the soil in your garden,The optimal soil is a blend that includes the mineral-rich dirt along with organicrich organic matter that plants need to thrive.


In my garden I try to compost as mutch as possible, so I can mix in the nutrient ritch compost in my soil. I use both hot composting of food scraps and cold composting of all organic garden “waste”..
If you dont have the time or space for composting, it is possible to get compost ready to use in garden centers and Community Composting.
You can read more on Community Composting here: https://www.epa.gov/sustainable-management-food/community-composting

If you are uncertain of the quality of your soil, you can get easy to use soil tests at amazon for 17 dollars. Check latest prices here: Soil testing kit.

Also remember to check out how much sunlight your growing area gets, and that the rain drains well. If you treat your soil well and plan you crops according to your climate you will succeed with any plant you want.

The satisfaction when you harvest your own produce is well worth the time you put in 🙂

BeeJay
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