Growing Watermelon

Best Planting Times for Watermelons in Colorado

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

Colorado’s varied climate, ranging from high plains to mountainous areas, requires careful planning for successful watermelon cultivation. The best practices involve timing the planting with appropriate soil temperatures and moisture levels, as well as considering local climatic conditions.

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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
Find Planting Trays on Amazon

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 lesser light conditions.
Grow Lights Image
Check out Grow Lights on Amazon

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 Colorado, using a greenhouse can help manage temperature fluctuations and extend the growing season. With the ability to control humidity, temperature, and light, it allows for a more stable environment that fosters healthy watermelon growth, especially in regions where the climate can be unpredictable. Overhead ventilation and shade options also help manage hot summer days.

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 Colorado, supplementing with fertilizer can ensure 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 Colorado around 1-2 weeks after the last expected frost date, ensuring that the soil has warmed sufficiently for optimal growth.

Average Last Frost Dates for Colorado’s Major Cities

CityAverage Last Frost Date
DenverMay 7
Colorado SpringsMay 15
AuroraMay 14
Fort CollinsMay 19
LakewoodMay 11
ThorntonMay 18
ArvadaMay 10
WestminsterMay 12
PuebloMay 23
CentennialMay 16

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

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 in your growing area gets, and that the rain drains of 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 🙂

Other planting guides for Colorado:

Kale Planting in Colorado

Broccoli Planting in Colorado

Pumpkin Planting in Colorado

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

BeeJay
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