Gardening in the mountains of Colorado presents a unique set of challenges. Temperature, intense sunlight, low humidity, short growing seasons, drying winds, extreme weather fluctuations, infertile soils, recurrent drought and wildlife damage all present difficult conditions for cultivation. plants in the High Country.
Common soil problems include: poor aeration, low organic matter and nutrient content, and rocky soils. Some soils also have a high pH which can create nutrient deficiencies in plants. Colorado soils are often high in iron, but the yellowing symptom of iron deficiency occurs because high concentrations of calcium in the soil “locks up” iron and makes it unavailable to growing plants.
That being said, you can:
- Plant in raised beds or containers
- Choose varieties that will grow well with existing soil conditions
- Select species that will improve soil qualities
Short growing seasons
Growing seasons tend to be shorter at higher elevations. Lower valley bottoms often have even shorter seasons due to the cold air sink from the surrounding mountains. The phenomenon of air drainage can also make a difference when determining where to place your garden. Avoid placing hedges, fences and other landscaping features that may obstruct air circulation. Cool night temperatures also delay the ripening of vegetables and flowers.
Extreme weather fluctuations
It is not uncommon for mountain communities to have an already short growing season interrupted by a “killing” frost. The real plant killers, however, are infrequent (but rapid) temperature changes. Temperature swings can scar trees and shrubs and serve to kill many plants at the edge of hardiness. Heavy, wet snowfalls can also occur in spring and fall. When this happens, trees, shrubs and garden flowers can be caught in full leaf or in full bloom. These snows, known as “limb breakers,” often cause physical damage that increases a plant’s susceptibility to insects and disease.
From the good side
High intensity sunlight in the mountains produces stronger stems and brighter flowers. The short growing season and cooler temperatures also extend the growing season for “cool season”. Plus, thanks to Colorado’s semi-arid climate, there are fewer insect and disease problems. By carefully selecting the appropriate plant species and using microclimates to your advantage, you can grow a successful and colorful garden of flowers, vegetables, trees and shrubs.
What to grow
Perhaps the most common question asked by new gardeners is “What can I grow here?” The answer is “fresh seasonal vegetables”. Most seed packets will distinguish between warm season and cool season vegetables. A rule of thumb is that warm season vegetables don’t like temperatures below 50 degrees Fahrenheit (and most of our summer nights drop below 50 degrees). As such, warm season vegetables will likely only thrive if they are in a greenhouse or inside your home on your windowsill. Examples of warm season vegetables include tomatoes, peppers, squash and basil.
Cool season vegetables are easier to grow and more successful in Middle Park. Green leafy vegetables, root vegetables and some peas are most notable for their viability in the High Country. Lettuce, spinach, kale, Swiss chard, arugula, bok choy, radishes, carrots, beets, parsnips, turnips, onions, snow peas and snow peas all are some of the vegetables that flourish in our climate.
When buying seeds, remember to make sure you are buying “cold season” varieties. You should also check how long the vegetable needs to reach maturity. Why is this important? We have a very short growing season in Grand and Summit counties, so it’s wise to choose vegetables that grow quickly. Some areas of Middle Park have fewer than 25 frost-free days per year. This is NOT a long time for vegetables to be ready to harvest. Therefore, avoid anything that needs more than 60-70 days to ripen. Luckily, most of these cool-season vegetables can withstand frost, so you do NOT have to panic every time it gets cold outside.
Perennial vegetables (like rhubarb, horseradish, chives, and asparagus) will come back year after year without much effort on your part. The roots will need a year or two to establish themselves, but once established they will delight you for years.
CSU Extension also has great resources for lawn and gardening. You might consider checking out these websites:
- Yard and garden: Extension.ColoState.edu/topic-areas/yard-garden/?target=publications
- Low Water Native Plants for Colorado Mountains: Extension.ColoState.edu/docs/pubs/native/MountainsSm.pdf
- Alternative Lawn and Garden Pesticide Management: Extension.ColoState.edu/docs/pubs/garden/xcm221.pdf
- Colorado Gardner Certified Program – Colorado Master Gardener: CMG.Extension.ColoState.edu/certified-colorado-gardener
- PlantTalk Colorado (information on many horticultural topics): PlantTalk.ColoState.edu
If you want to learn more about storing food at high altitudes, contact the Grand or Summit CSU extension offices. They can provide you with resources or arrange a course in food preservation.
You can also see the link below from CSU Extension for fact sheets on food storage and canning: Extension.Colostate.edu/topic-areas/nutrition-food-safety-health.
For more information on a variety of natural resources and rural living topics, see the Middle Park Conservation District’s “High Country Rural Living & Land Management” guide at MiddleParkCD.com/ultimate-landowner-guide.