High-Altitude Gardening Tips for Colorado Gardeners


It’s not quite warm enough to start gardening outside, but in Grand County, Colorado, it’s a great time to start your garden indoors! Begin planning for your glorious springtime garden by starting seeds indoors for transplanting outdoors later.  It’s also a good way to grow certain varieties of plants that are not readily available as transplants in the nursery.

But how do you start your garden indoors?

We asked Todd Hagenbuch, Agriculture Agent and County Director, Routt County CSU Extension, for expert advice on Colorado gardening!

What should I know about gardening in Grand County?

Gardening in Colorado is expectedly a little tricky. The growing season is short, and late-season frosts sneak up on us! It can be nerve-wracking to transplant seedlings into the Colorado soil. Grand County is quite varied when it comes to growing environments. Advice for a Grand Lake grower won’t necessarily be the same for someone in Kremmling or even Granby, which is right down the road!

Expert Tip: “Pay close attention to how the snow has piled up around your place and how it melts this spring as that shows you wind patterns and what areas are hotter and colder, which impact what you’re going to plant where and at what time. And […if you’re struggling to find Granby-specific information on gardening], check out Steamboat Springs, which has a similar growing season to Granby. ” – Todd Hagenbuch, Agriculture Agent, and County Director, Routt County CSU Extension

What growing zone is Grand County in? How does this impact our start season?

The USDA Plant Hardiness Zone Map is the standard by which gardeners and growers can determine which plants are most likely to thrive at a location. Hardiness zones are geographic areas that are categorized based on the average minimum winter temperature. These zones help gardeners determine which plants are suitable for their specific climate. The USDA’s map divides North America into 13 hardiness zones, ranging from zone 1 (coldest) to zone 13 (warmest). If you look on the back of your seed pack, it will tell you what zone the plant can tolerate!

Grand County has zones 3-5 depending on location. Because it is such a wide range, the zone isn’t always very helpful. More important is knowing when your last average frost dates are!

Expert Tip: “If you want to learn more about the subject of hardiness zones, check out this webinar!” – Todd Hagenbuch, Agriculture Agent, and County Director, Routt County CSU Extension

How do I successfully transition seedlings that I start inside to my garden?

In Granby, the most important thing you can do is to wait until the last average frost date before transferring your seedlings to the great outdoors. As a general rule, most annual veggies should start indoors 6 weeks before the last frost in your area. This will vary from town to town, but Grand County typically averages the last spring frost on June 1.

Expert Tip: Tom Hagenbuch also recommends “hardening” your seedlings: “To harden plants, start putting them outside for a couple of hours each day, lengthening the time gradually until you can leave them out overnight (again, making sure it’s after danger of frost). Do that for a few nights before planting. If you can cover the plants on cold nights (34 or less, but it depends again on the crop), that’s a good plan.”

Where should I go for expert advice?

A great resource for gardening advice is Colorado State University’s Master Gardener extension. They have a comprehensive vegetable planting guide, and master gardeners are accessible by email!

You can also refer to the Almanac (also known as the Old Farmer’s Almanac). You can pick up a print version or browse online for super regional tips and tricks, which is especially useful for Colorado gardeners! This page breaks down by crop type, when to start seeds indoors in Grand County, and when you are likely safe to transplant them.

Are you ready to start your Colorado garden?

Now that you have some information on how to set your high-altitude garden up for success, come to Country Ace for all your gardening supplies! Grab fertilizer for your garden beds, seeds for indoor starters, planters, and more! Stay tuned for May when we open our greenhouse! 

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