This is a topic we should have addressed much sooner, and it’s all our fault that we didn’t. The Gardzen Test Garden is located in coastal North Carolina, USA at roughly 46 feet/14 meters above sea level. Our low lying location and subtropical climate give us a bias towards the kind of gardening suited to that location. While we have experience in colder climates, we’ve never really worked at high altitude. With that in mind, we wanted to explore the world of high altitude gardening and offer some advice that our research has revealed. We’re especially indebted to the Colorado State University Extension and University of Idaho Extension for all the wonderful information they’ve gathered on the subject, and we’ll be linking to some of their articles here. We’re also drawing heavily on feedback and advice from Gardzen readers, and we’re always grateful to all of you!
· High altitudes lead to short growing seasons. It sounds obvious, but it needs to be said: higher altitude locations have shorter growing seasons than low altitude locations at similar latitude. This can cut a month off both the beginning and the end of the season, which in turn radically changes the gardening strategies involved. High altitude gardeners have gotten clever at finding work around like short-season veggie varietals, row covers and greenhouses, and indoor gardening in order to both extend and get the most out of their shorter seasons.
· Cold/Cool weather is a constant. There’s a reason that the USDA zone map takes both altitude and latitude into account when assigning zones for plant hardiness. Higher altitudes mean a thinner atmosphere and cool or cold weather even during the warmest part of the year. As one master gardener at the CSU extension puts it “We have had frost as late as July and as early as August. But, there are strategies that will make the best of the season we do have.” This can mean adopting approaches suited for cold weather, like deep mulching, plant covers, and other ways of dealing with the occasional cold snap at any time of the year.
· It gets hot, too. High altitudes and thin air mean more UV exposure from sunlight. This affects both gardeners and plants—make sure to wear sunscreen, drink water, and otherwise take steps to protect yourself from the sun. Watering is always a garden chore, but your high-altitude garden will need to be flexible in order to adapt to the extremes of weather that can happen with both hot and cold spells. You may also want to adopt sun shades for delicate plants during the bright and hot days, as they might benefit from a bit of sun protection too. Mountain locations may be subject to rain shadow and the resulting perennially dry weather, increasing the watering requirement even further.
· Choosing the right plants is important—and so’s finding the right place for them. So with all that in mind, a high altitude gardener would be wise to select plants suited for cool weather with occasional heat and sun along with a shorter growing season. This may sound challenging, but the reality is there are many garden plants available to our friends in the mountains and plateaus. Most annual herbs can be started indoors and grown in containers which can in turn be moved inside for the winter. Root veggies like radishes, beets, potatoes, carrots, turnips and parsnips can do quite well. Peas and beans—fast growing and resilient—are favorites in both dry and high altitude gardens. Likewise leafy veggies can often grow throughout the season and may be started indoors, so high altitude gardens are often lush with spinach, cabbage, kale, collards, and lettuce.
· Soil maintenance is a bit different. Altitude exacerbates the differences in soil we often see at low altitudes. River valleys often have rich soil, built up over year after year of erosion and flood. However all that soil has to come from somewhere, so mountains and high altitude desert may often offer rocky or sandy soil. The good news is that you can create the soil you need in raised beds, landscaping beds, or containers depending on your location and your needs. It takes time and care—composting may be a bit slower at altitude—but it can be done and many high altitude gardeners are doing it.
We’re still learning more, and we’re eager to hear more from people who have gardens in high altitude location. If you’re just getting started as a high altitude gardener, we hope this blog provides a starting point and links to further resources. If you’re experienced at gardening in a high altitude location, we’d love to hear from you and maybe interview you for a future article so please get in touch!
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