How to Grow Watermelons in Colorado

Growing watermelons in Colorado can be a rewarding endeavor. The state’s unique climate, characterized by its high altitude, low humidity, and diverse microclimates, presents both challenges and opportunities for gardeners. With some careful planning and attention to detail, you can cultivate these delicious fruits even in the Centennial State. This guide will take you through the key steps of growing watermelons in Colorado, covering everything from variety selection to harvest.

Understanding Colorado’s Climate

Colorado’s climate can significantly impact your gardening success, particularly when it comes to growing heat-loving plants like watermelons. With elevation ranges from around 4,000 to over 14,000 feet, temperatures can vary widely across the state.

• Growing Season: Watermelons require a long growing season of 70-90 frost-free days. In many parts of Colorado, especially at higher elevations, the growing season is limited. It’s essential to identify your local frost dates and choose watermelon varieties that mature within the available timeframe.

• Temperature: Watermelons thrive in warm temperatures. The ideal daytime temperatures are between 70°F and 95°F. Nighttime temperatures should ideally remain above 50°F. Be mindful of unexpected cold fronts that may threaten young plants.

• Sunlight: Watermelons need full sun for optimal growth. Aim for at least 6 to 8 hours of direct sunlight each day.

Choosing the Right Watermelon Varieties

When selecting watermelon varieties suitable for Colorado’s conditions, consider the following:

• Early Maturing Varieties: Choose varieties that mature quickly—typically within 70 to 80 days. Some good options include:
• Sugar Baby: A small, sweet personal-sized watermelon.
• Crimson Sweet: A larger variety with a sweet flavor and deep red flesh.

• Yellow Doll: Known for its yellow flesh and crisp texture.

• Seedless Varieties: If you prefer seedless watermelons, look for hybrid options that are bred for shorter growing seasons.

Preparing Your Garden Bed

Successful watermelon cultivation starts with proper garden preparation:

Soil Requirements

Watermelons thrive in sandy loam soil with good drainage. They prefer slightly acidic to neutral pH levels (around 6.0 to 7.5). To prepare your garden bed:

1. Soil Testing: Conduct a soil test to determine pH and nutrient levels.
2. Amendments: Depending on test results, amend the soil with compost or well-rotted manure to enhance fertility and structure.
3. Tilling: Till the soil to a depth of about 12 inches to ensure good aeration and drainage.

Location

Select a planting site that receives full sun and has good air circulation. Avoid low-lying areas where cold air settles, as this can lead to frost damage.

Planting Watermelons

When to Plant

In Colorado, it is best to start watermelon seeds indoors about 4-6 weeks before the last expected frost date. Transplant them outdoors after the risk of frost has passed and when soil temperatures have reached at least 70°F.

Direct Sowing vs. Transplanting

You can choose between direct sowing seeds into your garden bed or starting them indoors:

• Direct Sowing: If you live in an area with an extended growing season (like lower elevations), plant seeds directly into the prepared soil after the danger of frost has passed.
• Transplanting: Start seeds indoors in biodegradable pots if your growing season is short. This method gives you a head start and allows for earlier fruiting.

Planting Technique

1. Spacing: Space plants at least 3 feet apart in rows that are spaced about 6-8 feet apart.
2. Depth: Plant seeds about 1 inch deep or transplant seedlings at the same depth they were grown.
3. Watering: Water thoroughly immediately after planting to settle the soil around the seeds or seedlings.

Care and Maintenance

Once your watermelon plants are in the ground, proper care is critical:

Watering

Watermelons need consistent moisture, especially during their flowering and fruit-setting stages:

• Irrigation Methods: Drip irrigation is ideal as it reduces water waste and keeps foliage dry, preventing disease.
• Frequency: Water deeply once a week or more often during hot weather, aiming for about an inch of water each week.

Fertilization

Watermelons are heavy feeders:

• Use a balanced fertilizer at planting time.
• Once seedlings establish (after about four weeks), switch to a fertilizer high in phosphorus and potassium to promote fruit development.

Weed Control

Weeds can compete with watermelon plants for nutrients and water:

• Use mulch (straw or grass clippings) around plants to suppress weeds while retaining moisture.
• Hand-pull weeds carefully if necessary; avoid disturbing the roots of watermelon plants.

Pest and Disease Management

Monitor your plants for pests like cucumber beetles and aphids:

• Use row covers early on to protect seedlings from pests until they are robust enough.
• Organic insecticides like neem oil can be employed if infestations occur.

Be aware of diseases such as powdery mildew; maintaining good air circulation through spacing will help mitigate these risks.

Harvesting Watermelons

Knowing when to harvest is crucial for enjoying sweet, juicy fruit:

Signs of Ripeness

Look for these indicators that your watermelons are ready to be picked:

1. Color Change: The bottom spot where the melon rests on the ground will turn from white to a creamy yellow color.
2. Tendrils Drying Out: The tendrils closest to the fruit will turn brown and dry up.
3. Thumping Sound: Ripe watermelons will produce a hollow sound when tapped.

Harvesting Technique

Use sharp pruning shears or a knife to cut watermelons from the vine, leaving about an inch of stem attached. Handle them carefully, as they are heavy and can bruise easily.

Conclusion

Growing watermelons in Colorado poses unique challenges but is entirely possible with proper planning and care. By selecting suitable varieties, preparing your garden correctly, maintaining appropriate care throughout their growth cycle, and harvesting at the right time, you can enjoy fresh watermelons from your own backyard. Whether you’re indulging in sweet slices on a hot summer day or using them in refreshing salads, homegrown watermelons will surely be a highlight of your gardening efforts! Happy gardening!