Prepare plants for the great outdoors


By Dana Hayward
SUN Columnist

Gardening in Pagosa Springs, at elevations above 7,000 feet, can be a challenging endeavor.

Due to dry winds, low humidity, extreme temperature fluctuations, varied microclimates created by unique mountain topography and rocky, alkaline soils, many vegetable crops and flowers can have a difficult time thriving in the area (CSU fact sheet 7.244, “Colorado Mountain Gardening Basics;” CSU Fact sheet 7.220 “Colorado Gardening: A Challenge to Newcomers”).

Although the key to having a successful garden during the summer months is proper plant selection, which often entails growing primarily cool-season crops, many gardeners hope to grow coveted warm-season crops such as tomatoes, cucumbers, peppers and melons. Although not impossible to achieve, warm-weather crops are much more difficult to grow in the Pagosa Springs area than cool-season crops due to their intolerance of cold nighttime temperatures.

According to Colorado Master Gardener note No. 750, which includes valuable information about monthly temperatures, precipitation, snowfall and frost dates for communities in southwest Colorado, the average growing season in Pagosa Springs is only 77 days in length. Here in our community, there is a 50-percent chance of a 32-degree frost on June 22 of each year, with the chance of freezing temperatures increasing earlier in June and decreasing after this date. A 50-percent chance of a 32-degree frost marks the reasonable end of the local outdoor growing season on Sept. 7, with the likelihood of such a frost occurring after that date in September increasing significantly.

Due to the short growing season in the area, it is a good idea to start plants (that can be successfully transplanted) indoors prior to the reasonably assumed frost-free date of June 22.

Many cool-season crops such as kale, kohlrabi, lettuce, spinach, chard, beets, cabbage, snap peas and radishes can be direct-seeded approximately one month prior to the average last frost date, although many of these plants can also be started indoors and transplanted.

Cool season crops that take longer to mature, such as broccoli, leeks and Brussels sprouts, should generally be planted indoors and transplanted outdoors one or two weeks prior to the last frost.

Gardeners planning to grow coveted warm-season crops outdoors should start the plants indoors and take special care in transplanting. Choosing varieties of warm-season crops known to be more resistant to frost and to temperature fluctuations will increase the chance of successful growing (CSU fact sheet 7.244, “Colorado Mountain Gardening Basics”).

The key to the successful transplanting of any seedling is properly “hardening off” the transplant. According to Colorado Master Gardener Steve Aegerter, “hardening off” refers to the process of acclimating plants to new, harsh outdoor habitats by slowly introducing them to intense sun, winds and fluctuating temperatures (Extension article No. 1). Although hardening off seedlings is a bit of a process, it allows gardeners to avoid the tragedy of watching well cared for seedlings and starts struggle to adapt, grow and thrive in a generally harsh outdoor mountain environment.

Normally, the goal of growing seedlings indoors is to give them a good start — providing them with ideal growing conditions including consistent watering, fertilizing, light and temperatures. Although starting seedlings in a controlled environment helps them to germinate, the seedlings are not immediately ready to withstand the harsh, uncontrolled conditions of the outdoor garden environment. The good news is, with a little work, these plants can acclimate to their new outdoor environments.

According to Rodney Davis and Angela O’Callaghan with the University of Nevada Extension, factors that affect the amount of time and ease with which seedlings will adjust to the outdoor environment include the conditions under which the plants were grown, the outdoor conditions and site in which the seedlings will eventually be planted, and the biology of the plants themselves — the more tender and protected the seedlings are and the harsher the transplant environment, the longer it will take the plants to acclimate or “harden off.”

It is important to remember that although there are general guidelines for “hardening off” plants, there are no specific rules, as all plants respond to unique environments differently and similar plants are often “hardened off” to be successfully grown in myriad environments — any time a plant changes locations, it takes time to acclimate to its new environment.

For cool-weather and warm weather crop seedlings and other herbaceous plants, watering should be reduced during the “hardening off” process, although plants should not be allowed to dry out. Additionally, fertilization should cease and exposure to sun and moderate winds should increase over the course of a week or more. Exposure to depressed temperatures in increments is also an important part of the “hardening off” process, especially here in Pagosa Springs. All of these general steps will help the plants to toughen, preparing them for transplant into the great outdoors.

Seedlings and herbaceous plant transplants should be exposed to depressed temperatures for short periods at first, until they are able to withstand longer periods of cooler temperatures with little to no sign of stress.

Keep in mind that care should be taken to avoid the exposure of seedlings to freezing temperatures (University Nevada Reno “Hardening off Plants” Rodney Davis and Angela O’Callaghan Ph.D.).

During the “hardening off” process, it is critical to monitor plants closely, remain aware of temperature changes and be prepared to bring tender seedlings indoors in the event of frost. An adjustable cold frame can be a useful tool to the gardener during the “hardening off” process, as it can be used to moderate temperature fluctuations for seedlings. Once acclimated seedlings have been planted outdoors, it is also critical that the gardener remain attentive, ready to protect the transplants in the event of a frost using season extension techniques such as floating row covers, blankets, low tunnels or cloches (Steve Aegerter CMG Extension article No. 1).

Floating row covers are an excellent and generally inexpensive way for mountain gardeners to both protect tender transplants and to extend the growing season in the spring and fall by a couple of weeks. Row covers can be especially advantageous in mountain communities as they can be used throughout the growing season. Floating row covers allow light and moisture to reach the garden beneath, trap moisture, protect plants from dry winds and harsh, high-elevation sunlight and even deter wildlife, including deer and rabbits, from helping themselves to the produce in the garden.

For more information and resources about acclimating seedlings to the outdoor mountain climate in Pagosa Springs, please visit or contact the Archuleta County Extension office by calling 264-5931 or emailing questions to

Wildfire mitigation

Learn how to create a defensible space around your home, operate a chainsaw correctly and safely manage the oak brush around your home. To register or for more information, call the Extension office at 264-5931. Workshop dates and topics are as follows:

May 29: 10 a.m-noon. Chainsaw Safety, CSU Extension building, Archuleta County Fairgrounds. Operating a chain saw can be dangerous. Learn to operate this important tool safely and maintain it for optimum efficiency.

June 19: 10 a.m.-noon. On-site Defensible Space Workshop. These workshops will take you through the steps to create a wildfire defensible space around your home and structures. An on-site location in Archuleta County will be identified.

June 26: 10 a.m.-noon. On-site Oak Brush Management Workshop. Gambel oak is one of our most common and prolific shrubs. Learn how to manage this shrub for greater wildfire prevention. A location within the county will be identified for this hands-on training.

CPR and first aid

CPR and first aid certification classes are offered monthly by the CSU Extension office on the second Monday and Wednesday of each month from 6-10 p.m. Anyone needing to receive or renew certification can register by calling the Extension office at 264-5931.

We will also schedule classes on additional dates with five or more registrations. Cost for the classes is $80 for combined CPR/first aid, $55 for individual CPR or first aid and $35 for recertification with proof of current certification. The type of first aid information provided will vary by the needs of the audience.