High Altitude Gardening

March 11, 2014 @ 5:15 pm

How far above sea level is it, really? Approximate elevation for the Teller County areas are: Cripple Creek 9500 ft; Divide 9100 ft; Florissant 8200 ft; and Woodland Park 8500 ft. That could mean very little to some or be significant to others. To gardeners it’s a limiting, yet not debilitating, factor. The distinction between what plants can survive versus what will thrive results from the suitability and/or adaptability of the plant to the supporting environment. Colorado mountain environments offer soil with very little water holding capacity and low nutritional value; sun exposure that can be desiccating; temperatures are rarely sizzling and can hit way below freezing; infrequent rainfall and variable snow fall (any time of the year) and a short growing season.

Site Selection

For any garden the primary elements that will dictate success are soil and the amount of sun and water. Organic matter added to any soil enhances the water holding capacity and nutritional value. It can constitute home generated or store bought compost, aged manure or bagged products from the garden centers including mushroom, alfalfa, cotton burrs, etc. Generally 2-3” of organic matter worked thoroughly into the top 12” of soil makes a good starter soil or foundational base for a lawn. The serious vegetable grower may want to bring in a good blend of soil for raised beds then re-invest with amendments each year. For a landscape using only native plants, a little organic matter in the initial hole with supplemental water the first few years should be good enough.


Lighting can be direct sun, indirect or filtered, cooler sun in the morning, hotter in the afternoon or all day with added heat reflected off an object and/or structure. There may even be a combination of several of those. Knowing what the site has to offer will help plug in the right plant. Consider that 3 hours or less of direct sun will support a ‘shade’ loving plant. Filtered sun for half of the day would also support a shade plant, while filtered all day sun will probably support a ‘partial shade’ plant. A plant wanting ‘partial shade’ will do well with 3-5 hours of sun a day. ‘Full sun’ plants require 6-8 hours direct sun for best performance. Most vegetable gardens are positioned for maximum sun light since healthy tops and/or blooms result in the edible produce. During the peak of summer heat, even the ‘full sun’ plants may wane, like many people. If, with adequate water, they rebound in the cool of the evening, know that it’s just the heat. Overwatered plants give the same symptoms of drought, which is wilting, due to lack of oxygen in the soil. If plants don’t rebound in the cool of the evening, move them to a cooler site to relieve stress (if you can) and hold up on the water until they recoup.


Watering is probably most misunderstood since under the soil surface is the unknown. Roots will develop where the water goes, but if the soil stays soggy due to frequent shallow sips, the roots stay shallow because of lack of oxygen. If the water isn’t allowed to drain out from below the roots, then salts and calcium’s (in the water) can accumulate and cause further problems. The best watering practices are generous and infrequent. Initial water for a newly transplanted plant should be thorough; enough to settle the surrounding soil. To determine when the plant needs water again is to wait until it goes to a slight wilt. If it takes 5 days to wilt then water generously every 4 days. Obviously more water is needed in the dry heat than the cool spring or fall. Adding 2-3” of mulch can eliminate approximately one watering per week during the summer.

Winter watering is very important especially if there has been no snow for a month. By the end of October most deciduous perennials, shrubs and trees have lost their leaves and have very little evapotranspiration. Evergreens will lose more moisture through their needles because of our “Indian Summers”. Because the soil has very little water holding capacity, it’s important to water monthly until there’s adequate snow. Lack of moisture and freezing temperatures can attribute to ‘freeze dried’ plants. Choose a warm day and make sure the plants that are most exposed to wind and sun get a big drink. Mountain temperatures don’t heat up until mid-June (night time temps matter too) or later and that’s when the full water schedule can get put back into effect.

Growing Season

The average last killing frost of spring is around June 15 and the average first killing frost is September 15. That’s right, only 90 days and that’s hardly enough time to reap the benefit of what’s been sown. That’s why many gardeners start plants inside early and/or provide shelter(s) to protect their plants and extend their growing season. (See Teller County Master Gardener Article Growing Vegetables)

Other Challenges

Deer and Elk provide beauty to the mountains, but to the gardener, they can be another hindrance to a thriving garden! Although they are particular to some plants and not others, it’s advisable to do some research before planting. The research may be for Preventing Deer Damage (http://www.ext.colostate.edu/pubs/natres/06520.html). Then there are the rabbits and voles so you may be researching for building a protected garden.

Weather offers another element that can bring down a garden in 15 minutes or less: Hail. Disease or insects can easily move into the vulnerable exposed areas of the plant so clean up the dead material, trim for health and within a few days begin a nitrogen fertilizer to try to regain strength in the plant.

Success is not easily achieved for the mountain gardener, but there’s nothing sweeter than a successful garden in the mountains!

Author Administrator Category How-Tos