Growing Watermelon

Best Planting Times for Watermelons in Utah

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

Planting Conditions

Watermelon Planting Conditions

Utah’s climate varies significantly across the state, from desert-like conditions in the south to cooler mountainous regions in the north. For optimal watermelon cultivation, it’s crucial to consider your local microclimate and the USDA Hardiness Zones, which typically range from 4b to 9a.

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Useful Tools for Starting Watermelons Indoors

Using the right tools can save you time and increase your success rate.

Seeds

Quality seeds lead to better germination and healthier plants. Starting with high-quality seeds gives your watermelons the best chance to thrive from the very beginning.
5 pack of different Melon Seeds
Browse Watermelon Seeds on Amazon

Planting Trays

Planting trays help you organize your seedlings and ensure they have enough space to grow before you transplant them outdoors. This makes the process more efficient and increases the chances of strong, healthy plants.
Planting Trays Image
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Grow Lights

Grow lights are essential if you don’t have enough natural sunlight. They provide your seedlings with the light they need to grow strong and healthy, even in less-than-ideal conditions.
Grow Lights Image
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Seed Starting Soil

Using light, fine soil specifically designed for seed starting helps young roots establish quickly and promotes healthy growth. It’s an easy way to give your seedlings the best start possible.
Seed Starting Soil Image
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Greenhouse Growing

In Utah, where temperature extremes can be a concern, a greenhouse provides a stable environment that promotes optimal watermelon growth. Greenhouses allow you to extend your growing season, protect your plants from harsh weather, and facilitate year-round cultivation with appropriate climate control.

Consider investing in a 10×12 FT Greenhouse priced at $1,199 to ensure your watermelons thrive in a controlled environment.
Greenhouse Image 1
Greenhouse Image 2
Check the latest price on Amazon.

Fertilizer

For optimal watermelon growth in Utah, supplementing with fertilizer can lead to abundant and healthy harvests. Quality fertilizer helps replenish nutrients in the soil and promotes vigorous plant growth.
Fertilizer Image
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Plant watermelons outdoors in Utah approximately 1-2 weeks after the last spring frost date, ensuring the soil is warm enough for optimal growth.

Average Last Frost Dates for Utah’s Major Cities

CityAverage Last Frost Date
Salt Lake CityMay 11
ProvoMay 15
OgdenMay 8
St. GeorgeApril 15
LoganMay 22

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 Utah:

Broccoli Planting in Utah

Pumpkin Planting in Utah

Tomato Planting in Utah

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

Starting Watermelons Indoors

In Utah (Zone 6a), begin indoor watermelon seed starting between April 1 and April 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 60 inches between rows for optimal growth.

General Care and Maintenance

Watering

  • Provide deep watering to keep the soil consistently moist, especially during hot and dry periods typical in Utah’s climate.
  • Water at the base of plants to prevent leaf wetness, which helps to reduce the risk of fungal diseases.

Fertilizing

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

Pest and Disease Management

  • Regularly monitor for common pests such as aphids, cucumber beetles, and powdery mildew. Utah’s dry climate can help mitigate some pest pressures, but vigilance is still key.
  • Implement organic or integrated pest management methods to protect watermelon plants from pests and diseases effectively.

Harvesting

  • Harvest watermelons when the tendril nearest to the fruit begins to dry out, and the fruit has a deep, dull color. Regular harvesting encourages further fruit development.

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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