Growing Plants in a Desert Environment

It is a common lament made by those who are trying to grow plants in the desert for the very first time.

“Where I lived before, I could just throw out the seeds and everything would grow, but here, in the desert, the plants die, no matter what I do!” 

I know many people are frustrated in their attempts to grow healthy, vigorous plants, because I hear from them on a regular basis.  You may be one of them.

You plant, water, fertilize, and kindly talk to your plants even, but they do not seem to respond, no matter what you do.  Unfortunately, it is a true but sad state of affairs. Newcomers to desert gardening, and many old-timers, often find frustration before they find success.

I want to tell you, though, there is hope! Once you become accustomed to the rules governing desert gardening, there is no reason why you cannot join the ranks of those who find growing plants in Southern Arizona an extremely rewarding experience. 

The desert is an ideal place to raise fruits, vegetables and ornamental plants.  Successful desert gardeners enjoy lush, thriving landscapes and beautiful flower beds.  Others enjoy producing much of their own food in successful, healthy gardens.  There are three reasons why gardening in the desert can be a satisfying experience.

First, the environmental factors that make Southern Arizona a desert are the same factors that allow a wide variety of plants to be grown in our area.  Fruits from apples to lemons and ornamentals from pines to palms can be successfully cultivated.  The almost unlimited possibilities have produced landscapes of great variety and interest.

Second, the exact same environmental conditions also allow a year-long growing season.  With the correct cultural practices, fresh vegetables can be harvested all year long; beautiful, fresh cut flowers can grace an indoor table every month of the year and turf areas can be green and lush twelve months out of the year.  Many area gardeners find the unlimited possibilities both challenging and satisfying. 

Finally, the cultural practices necessary to successfully grow garden and landscape plants have been worked out and published for all to know.  By learning how to deal with the environmental conditions and by carefully adhering to correct gardening principles, most people should have little trouble enjoying the fruits of their labors.

Assuming that you have bought into believing that success is possible, we are ready to address some of the more important factors that sometimes get in the way of healthy gardens and landscapes.  These factors generally revolve around climate and soil.

Southern Arizona’s climate is determined by its latitude, elevation and geography.  The latitude, or the distance from the earth’s poles, determines the amount of solar radiation, or sunlight, that a location receives.  Solar radiation is critical because it drives photosynthesis, the life process that is so necessary for plant growth.  The more solar radiation, the more vigorous the growth of plants. Since we are closer to the equator than many parts of the country and because of our generally bright, cloudless days, we receive more solar radiation.

Elevation has a great effect upon our climate.  Take temperature, for example.  Generally, the higher the elevation in Arizona, the lower the average temperatures, both during the day and night.  At our relatively low elevations, warm temperatures create a year round growing season. 

Every plant has an upper limit and a lower temperature limit.  In our desert, both extremes can affect plant health and growth.  It is just as important to protect our plants from the high temperatures of summer by watering correctly as it is to protect tender young plants from frosts in the winter.  Plants cool themselves by releasing evaporated water through tiny pores on the bottom of their leaves and the release has the same effect as a swamp cooler in our homes.  If plants run short of water, they die.

Nighttime temperatures also influence the growth of plants.  Some plants, such as our winter vegetables, do best when night temperatures are around 50 degrees F., while others do best when the temperatures are 60 degrees F. or higher.  Bermudagrass, for example, usually does not start to grow well in the spring until night temperatures reach 60 degrees F.

Rainfall, another climatic factor, is almost always insufficient to grow plants.  Many make this mistake, even with supposedly desert hardy low water use plants.  To maintain good plant health, rainfall almost always must be supplemented with irrigation, especially when plants are young and just getting started.  Proper irrigation is essential for good plant health.

Humidity affects the health of plants in may ways.  On the positive side, low humidity stifles the growth and development of many plant diseases.  For this reason, plants growing in the desert are often disease free as compared with similar plants growing in a more humid environment.  On the down side, the low humidity of June and July means that plants must be irrigated more frequently and with greater amounts during those months in order to keep them healthy. 

Wind can definitely be a factor.  The strong, dry winds of the desert can quickly dry out tender plants and send them into a tailspin of leaf injury and dessication.  In addition, most people have seen the flotsam and jetsam of broken branches and tipped over trees after our summer storms. Proper irrigation, correct staking and good pruning techniques will take care of most wind issues.

Geography, the features of the land such as mountains and valleys, affects microclimates as well as soil.  Microclimates are pockets and places where climatic conditions vary somewhat from the norms of the desert climate.  Planting strawberries on the north side of a home or fence will often allow them to grow through the summer where a south facing exposure would probably kill them off during the warm months. 

Our geography also determines many of the soil factors that impact plant growth.  The broad, flat valley floors where most people live were developed though many years of erosion that brought soil particles down from the surrounding mountains to fill the low lying basins.  Because of this, there is a wide variety of soil types that affect plants differently and these must be understood to successfully manage the growth and development of plants.  Alkali, salinity, low nitrogen fertility, pH, caliche and compaction all find their roots in the dry climate of the desert.

While there is not time, nor space, to talk about all of the factors in detail, it is important to be aware of them and to take the time to know how to deal with them.  Let’s continue to talk about them in the future.
                   
Success is possible in growing healthy and productive landscape and garden plants.  The most important rule of desert gardening and landscaping is to learn how to work with the environment instead of against it.

If you have questions, or you would like more information on any of these topics, visit with one of the Master Gardeners at the Cooperative Extension office, 820 E. Cottonwood Lane, Building C, in Casa Grande.  The telephone is (520) 836-5221.  The author’s email address is gibsonrd@ag.arizona.edu.

The University of Arizona is an equal opportunity, affirmative action institution.  The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.

Rick Gibson
Extension Agent, Agriculture, Pinal County
University of Arizona Cooperative Extension
820 E. Cottonwood Lane, Building C
Casa Grande, Arizona 85222
Voice:    (520) 836-5221
Fax:    (520) 836-1750
email:    gibsonrd@ag.arizona.edu