When To Plant Squash In Colorado

The best time to plant squash in Colorado is from late May to early June, after the last frost date has passed.
 
Colorado’s growing season is short, so timing is everything when you plant squash.
 
If you plant too early, a late spring frost can wipe out your seedlings overnight.
 
If you plant too late, your squash might not have enough time to mature before the first fall freeze.
 
That’s why knowing exactly when to plant squash in Colorado matters so much.
 
In this post, we’ll cover when to plant squash in Colorado, how elevation affects your planting schedule, and tips to get a healthy harvest.
 
Let’s dig in.
 

When to Plant Squash in Colorado

Knowing when to plant squash in Colorado comes down to two things: your local frost dates and your elevation.
 
Here’s what you need to know.
 

1. Wait Until After the Last Frost

Squash is a warm-season crop, and it hates cold soil.
 
In most parts of Colorado, the last frost typically falls between mid-May and early June.
 
That means you should plant squash in Colorado after that date, once the soil has warmed to at least 60°F.
 
If you plant squash too early, the seeds may rot in cold, wet soil instead of germinating.
 

2. Watch Your Elevation

Colorado’s elevation changes everything about when to plant squash.
 
If you live in Denver or the Front Range, you can usually plant squash in late May.
 
If you’re in the mountains or at higher elevations, you may need to wait until mid-June or even later.
 
Higher elevations mean shorter growing seasons and cooler nights, so planting squash in Colorado at 8,000 feet looks very different from planting in Pueblo.
 

3. Check Your Local Frost Date

The best way to nail down when to plant squash in Colorado is to check your local frost date.
 
The Colorado State University Extension and local gardening groups publish frost dates by region.
 
Once you know your average last frost date, count forward about one to two weeks.
 
That’s your green light to plant squash in Colorado.
 

How to Plant Squash in Colorado

Once you know when to plant squash in Colorado, the next step is getting it in the ground the right way.
 
Here are a few tips to help your squash thrive.
 

1. Warm the Soil First

Squash seeds germinate best in soil that’s at least 60°F.
 
If your soil is still cool, cover the planting area with black plastic for a week or two before you plant squash.
 
This traps heat and gives your seeds a cozy start.
 

2. Plant in Full Sun

Squash needs at least six to eight hours of direct sunlight every day.
 
Choose a spot that gets plenty of sun and has well-draining soil.
 
When you plant squash in Colorado, good drainage matters because our afternoon thunderstorms can waterlog the roots fast.
 

3. Use Row Covers for Protection

Even after the last frost, Colorado can throw a surprise cold snap your way.
 
Row covers or cloches protect young squash plants from chilly nights.
 
Just remember to remove them once the weather warms up so pollinators can reach the flowers.
 

Best Squash Varieties to Plant in Colorado

Because Colorado’s growing season is short, choosing the right variety matters as much as knowing when to plant squash.
 
Here are some favorites that perform well here.
 

1. Summer Squash

Zucchini, yellow crookneck, and pattypan are all reliable choices.
 
They mature in about 50 to 60 days, so they’re perfect for Colorado’s shorter season.
 

2. Winter Squash

Butternut, acorn, and delicata need a longer season, usually 85 to 100 days.
 
If you plant squash varieties like these, start them indoors in early May and transplant them after the last frost.
 

3. Short-Season Varieties

Look for varieties labeled “short-season” or “early.”
 
These are bred to mature quickly, which is a huge advantage when you plant squash in Colorado.
 

Common Mistakes When You Plant Squash in Colorado

Even seasoned gardeners run into trouble when they plant squash in Colorado.
 
Here are a few mistakes to avoid.
 

1. Planting Too Early

This is the biggest one.
 
It’s tempting to plant squash as soon as the sun comes out in April, but cold soil and frost will set you back.
 
Wait until the soil and the calendar both say it’s time.
 

2. Skipping Mulch

Mulch keeps moisture in and weeds out.
 
It also helps regulate soil temperature, which matters when you plant squash in Colorado’s unpredictable spring weather.
 

3. Forgetting to Water Deeply

Squash has shallow roots and needs consistent moisture.
 
Water deeply once or twice a week rather than giving light daily sprinkles.
 
This encourages strong root growth and healthier plants.
 

So, When to Plant Squash in Colorado?

The best time to plant squash in Colorado is after the last frost, usually from late May to early June, depending on your elevation.
 
Wait for warm soil, pick a sunny spot, and choose short-season varieties for the best results.
 
If you follow these tips, you’ll know exactly when to plant squash in Colorado and enjoy a bountiful harvest all summer long.