Growing Watermelon

Best Planting Times for Watermelons in Indiana

Planting MethodActivityRecommended Dates
Outdoor PlantingIndoor Seed StartingApril 15 – May 15
Transplant OutdoorsMay 31 – June 15
Greenhouse PlantingYear-roundAdjust planting based on temperature control in the greenhouse

Planting Conditions

Watermelon Planting Conditions

Indiana’s humid continental climate offers a unique blend of hot summers and cold winters. This requires careful planning for watermelon cultivation, especially to ensure the seeds are planted after the last frost for optimal growth.

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Useful Tools for Starting Watermelons Indoors

Using the right tools can significantly improve your chances of success when starting watermelon seeds indoors.

Seeds

High-quality watermelon seeds provide the best chance for a successful garden. Starting with premium seeds ensures a higher germination rate.
5 pack of different Melon Seeds
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Planting Trays

Planting trays help organize your seedlings and ensure they have ample space to grow before transferring them outdoors, leading to healthier growth.
Planting Trays Image
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Grow Lights

Grow lights are crucial if natural sunlight is insufficient. They provide essential light for growing strong seedlings, vital in Indiana’s shorter daylight periods during winter months.
Grow Lights Image
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Seed Starting Soil

Using specially formulated seed starting soil helps to ensure young roots establish quickly, promoting robust growth.
Seed Starting Soil Image
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Greenhouse Growing

In Indiana, fluctuating temperatures can challenge outdoor watermelon growth. A greenhouse provides a consistent climate that protects plants from extreme weather, allowing for an extended growing season and potentially year-round cultivation with proper management.

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 Indiana, applying fertilizer ensures healthy yields and replenishes soil nutrients necessary for robust plant development.
Fertilizer Image
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Plant watermelons outdoors in Indiana around 1-2 weeks after the last frost date, ensuring the soil is adequately warm for optimal crops.

Average Last Frost Dates for Indiana’s Major Cities

CityAverage Last Frost Date
IndianapolisApril 21
Fort WayneApril 29
EvansvilleApril 15
South BendApril 27
CarmelApril 25
FishersApril 24

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 Indiana:

Kale Planting in Indiana

Pumpkin Planting in Indiana

Tomato Planting in Indiana

Any questions on growing watermelons? Visit our forum to discuss: Growing Watermelons.

Starting Watermelons Indoors

In Indiana (Zone 5b), 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 24-36 inches apart in rows with at least 36-48 inches between rows for optimal growth.

General Care and Maintenance

Watering

  • Provide consistent and deep watering to maintain evenly moist soil. Indiana’s varying rainfall means regular watering may be necessary during dry spells to ensure proper growth.
  • Water at the base of plants to avoid leaf wetness, reducing the risk of fungal diseases.

Fertilizing

  • Apply a balanced fertilizer during planting and again when the plants begin to flower. Incorporating compost before planting can enhance soil fertility and structure.

Pest and Disease Management

  • Regularly monitor for common pests like aphids, spider mites, and cucumber beetles. Indiana’s humid summers can attract pests, so vigilance is key.
  • Implement organic or integrated pest management methods to protect watermelon plants from pests and diseases.

Harvesting

  • Harvest watermelons when they reach the desired size and the rind has a dull finish. The tendril closest to the fruit should be brown, indicating ripeness.

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 organic rich organic matter that plants need to thrive.


In my garden I try to compost as much as possible, so I can mix in the nutrient rich compost in my soil. I use both hot composting of food scraps and cold composting of all organic garden “waste”..
If you don’t 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 your 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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