Colorado Planting Zones

Colorado’s planting zones, altitude and climate conditions present obstacles with gardening. Despite the challenges of growing in Colorado, a greenhouse can extend your growing period and allow you to plant a wider variety of vegetables.

In this article, you will learn:

The state spans across five different growing zones (3, 4, 5, 6, and 7) with the average minimum temperature sitting between -40° and 5° F (-40° and -15° C). By understanding your state and the many planting zones it covers, you’ll be able to make the most of your growing season.

Image from Natural Resources Canada

Characteristics of Colorado Planting Region

The Colorado climate is incredibly diverse, and most areas will experience a range of extreme weather conditions such as:

  • High winds
  • Snowfall
  • Fierce storms
  • Tornadoes
  • Wildfires
  • Droughts

The higher altitude also poses additional challenges, from early frosts to significant temperature fluctuation.

However, most of the state will experience a peak growing season between June and August with long, hot, and sunny days.

Photo by Vincent Ledvina on Unsplash

Challenges of growing in Colorado

1. Shorter Growing Season

Coloradans can expect a peak growing season for only a handful of months out of the year. The best summer months for planting are between June and August; however, other areas of the state may experience an even shorter growing time frame.

2. High Altitude

Mountainous areas can be subjected to various extreme conditions, ranging between low humidity, temperature drops, poor soil characteristics, and high-intensity sunlight. Learn more about gardening in a high-altitude region.

3. Temperamental Weather

Weather conditions in Colorado are a complete wildcard. Some years will be overly dry and plagued with aggressive wildfires, while others may be unseasonably cold with an extended frost season. Planning and monitoring the weather are crucial components for the success of your garden.

4. High Winds

A combination of the towering Rocky Mountains and cold pressure systems create high-strength winds that can get up to speeds of 100mph. Without proper covering and protection, these winds can easily damage your hard work.

5. Wildlife

Colorado has an abundance of beautiful wildlife. However, birds, beers, deer, and more may take a liking to your garden and eat away at your hard work. Having a covered or enclosed garden space will help keep your plants safe and out of harm’s way.


The Benefits of Using a Greenhouse in Colorado

Unpredictable and extreme weather, shorter growing seasons, and higher altitudes make Colorado the ideal location for greenhouse growing. Not only will a greenhouse help extend your planting season, but it’ll also protect your plants from heavy rain and snow, hungry animals, wind gusts, and much more. 

1. Extend your growing season

  • Without a greenhouse: 
    The growing season for those gardening outdoors is limited to around three months on average. The season is relatively short in this region, meaning many vegetables won’t be able to mature prior to the first frost of the season without an element of indoor growing. 
  • With a greenhouse: 
    A greenhouse can help extend your planting season in Colorado to at least seven months, with the potential for up to nine months, depending on what part of the state you’re located. This means you could double or triple your season with a little assistance.

Learn more about specific growing dates for your area and the best vegetables to plant in each part of Colorado.


Customer images of the Sungrow Greenhouse in Colorado

2. Grow a Wider Variety of Vegetables 

  • Without a Greenhouse:
    Considering a majority of Colorado sits at a higher altitude, it’s recommended that you opt for cool-season vegetables for your outdoor garden to minimize the risk of losing your crops to early frosts or other unexpected weather changes. Unfortunately, options are very limited, but the following vegetables are known to thrive outdoors in this region: 
    • Lettuce
    • Broccoli
    • Brussel Sprouts
    • Cabbage
    • Collards
    • Spinach
    • Kale
    • Radishes


    • With a Greenhouse:
      Those using a greenhouse have countless options when it comes to planting a vegetable garden. Warm-season crops will thrive indoors without the need to transplant them at a later date. You can feel confident growing the following vegetables in your greenhouse:
    • Tomatoes
    • Beans
    • Corn
    • Cucumbers
    • Eggplant
    • Bell Peppers
    • Jalapeños
    • Zucchini
    • Tomatillo
    • Artichoke
    • Melons
    • Poblano Peppers
    • Cauliflower
    • Green Beans
    • Squash
    • Sweet Potatoes
    • Pumpkins
    • Celery
    • Lima Beans
    • Okra
    • Habanero Peppers


    Photo by Vasile Stancu on Unsplash

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