Growing Watermelon

Best Planting Times for Watermelons in Missouri

Planting MethodActivityRecommended Dates
Outdoor PlantingIndoor Seed StartingApril 15 – May 15
Transplant OutdoorsMay 30 – June 15
Greenhouse PlantingYear-roundAdjust planting based on temperature control in the greenhouse

Planting Conditions

Watermelon Planting Conditions

Missouri provides a warm, humid climate with USDA Hardiness Zones stretching from 5b to 7a, suitable for growing watermelons. The growing season typically lasts from late spring to early fall, making it important to timing your planting correctly for the best yields.

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Useful Tools for Starting Watermelons Indoors

Using the right tools can significantly enhance your chances of successful watermelon cultivation.

Seeds

High-quality seeds are essential for better germination and robust plants. Selecting premium seeds gives your watermelons a strong start.
5 pack of different Watermelon Seeds
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Planting Trays

Using planting trays helps you manage your seedlings and provides enough space for their growth before transplanting. This ensures a smoother transplantation process and healthier plants.
Planting Trays Image
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Grow Lights

Grow lights are essential if natural sunlight is insufficient. They ensure seedlings receive the necessary light for robust growth, even in less-than-ideal conditions.
Grow Lights Image
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Seed Starting Soil

Using light, specialized seed starting soil promotes quick root establishment and healthy growth, giving your seedlings the best start possible.
Seed Starting Soil Image
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Greenhouse Growing

In Missouri, where humidity levels can affect watermelon growth, using a greenhouse can provide a controlled environment that optimizes conditions for flourishing plants. This allows for extended growing seasons, protection from pests, and minimized risks of disease.

Consider investing in a 10×12 FT Greenhouse priced at $1,199 to ensure your watermelons thrive in a sheltered environment.
Greenhouse Image 1
Greenhouse Image 2
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Fertilizer

To ensure healthy watermelon growth in Missouri, using fertilizer will help replenish soil nutrients and stimulate vigorous plant growth.
Fertilizer Image
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Plant watermelons outside in Missouri approximately 1-2 weeks after the last spring frost date, ensuring that the soil is warm enough for optimal growth.

Average Last Frost Dates for Missouri’s Major Cities

CityAverage Last Frost Date
St. LouisApril 7
Kansas CityApril 15
SpringfieldApril 15
ColumbiaApril 21
Jefferson CityApril 21

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 Missouri:

Broccoli Planting in Missouri

Pumpkin Planting in Missouri

Tomato Planting in Missouri

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

Starting Watermelons Indoors

In Missouri (Zone 6a), begin indoor watermelon seed starting between April 1 and April 30. This timeline ensures healthy seedlings ready for outdoor transplantation starting from mid-May when the risk of frost has passed.

Transplanting Watermelon Seedlings

Transplant watermelon seedlings outdoors from May 15 to June 1, ensuring the soil temperature has consistently warmed above 70°F. Space the seedlings 36-42 inches apart in rows with at least 6-8 feet between rows for optimal growth.

General Care and Maintenance

Watering

  • Provide consistent and deep watering to maintain evenly moist soil, especially during dry summer months in Missouri.
  • Water at the base of plants to avoid leaf wetness, thus reducing the risk of fungal diseases common in humid conditions.

Fertilizing

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

Pest and Disease Management

  • Regularly monitor for common pests like aphids, cucumber beetles, and downy mildew. Prompt action is essential to manage these threats effectively.
  • Implement organic or integrated pest management methods to protect watermelon plants from pests and diseases.

Harvesting

  • Harvest watermelons when they are firm, have a uniform color, and when the tendril closest to the fruit begins to dry. Regular checking ensures optimal harvesting time.

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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