Why Science? - June 10, 2015
Jeff Schalau, Agent, Agriculture & Natural Resources
University of Arizona Cooperative Extension, Yavapai County

The University of Arizona Cooperative Extension, educates the public using science-based information and practices that can ultimately improve quality of life for local residents. Examples of science-based horticulture practices are: crop rotation, improved tree/shrub planting methods, discretionary use of fertilizers, adding organic matter to improve soil structure and fertility, and the application integrated pest management (IPM) principles. Horticultural practices that have little or no proven basis in science include biodynamic gardening, companion planting, planting by lunar cycles, using compost teas to prevent plant disease, using Vitamin B1 and other “miracle” products to improve planting success, and the list goes on.

What constitutes science? The scientific method begins with observations which lead to questions. From these questions, a hypothesis may be formed. A hypothesis can be tested through predictions of a given experimental response. Next, experiments are designed to test predictions. These experiments generate data which can be analyzed in a statistically valid manner. Depending on the results, the hypothesis may be accepted or rejected. Often, the hypothesis is modified, refined, or altered and further experiments designed and performed. Along the way, experimental results are verified by other expert researchers and a theory is generated. This verification uses a process called “peer-review” which is conducted by experts with similar areas of expertise before the results are published in scientific journals. The published results are also openly reviewed by the scientific community after publication. Over time, results of experiments are replicated and subjected to review by others. If the results are consistent, the theory becomes accepted.

The body of science is large and sometimes controversial. Many times, controversial theories drive some stakeholder groups to seek alternative information which supports their point of view or belief system. Mass media (newspapers, radio, television, the Internet, etc.) sometimes provides a venue for these alternative views to become amplified and the result can be polarization of our society. Arguments ensue and science is sometimes cast aside in favor of beliefs and popular opinion. This topic was recently featured in the March 2015 edition of National Geographic Magazine in an article called “Why Do Many Reasonable People Doubt Science?” by Joel Achenbach (a link to this article is included with the on-line version). I found this article very intriguing.

Now that I probably alienated half of my readers by stating my “beliefs” about science, I’ll delve into the topics of science and gardening. There is a large body of research related in the area of plant science we call “gardening”. My nationwide Cooperative Extension colleagues and I are charged with distilling this information and making it practical and usable by everyday people across the country. I strive to advocate for science while also respecting an individual’s beliefs.

In my work as a University of Arizona Cooperative Extension Agent, I present and encourage the use of science-based decision making. Over the past 18 years of writing this column, I have relied on science-based information to convey horticultural concepts and practices. Applying this information should enhance a gardener’s success when coping with pests, diseases, and environmental factors in gardens, orchards, and landscapes. From time to time, scientific research has altered accepted theories and I’ve updated my educational efforts accordingly.

One of my science-based gardening heroes is Dr. Linda Chalker-Scott, Extension Urban Horticulturist at Washington State University. She regularly conducts literature reviews of gardening topics. Formal literature reviews are specialized scientific publications that look at the overall body of science on a particular topic to examine the current state of science on a given topic. Given her Extension mission, Dr. Scott’s literature reviews are often less formal and more practical. They are written in easily understandable language and published online. She also cites the original scientific sources that generated the information. She calls these “Horticultural Myths” and I find them most interesting (see resources linked below).

I hope readers continue to adopt objective, science-based gardening practices and question information sources that rely on marketing ploys and hearsay. I would recommend that internet information be scrutinized for a scientific basis. Internet sites with abundant ads should be questioned and those using science and include “edu” in the URL are more likely to have objective information. A good place to start is Cooperative Extension!

Follow the Backyard Gardener on Twitter – use the link on the BYG website. If you have other gardening questions, call the Master Gardener help line in the Camp Verde office at 928-554-8992 or e-mail us at verdevalleymg@gmail.com and be sure to include your name, address and phone number. Find past Backyard Gardener columns or provide feedback at the Backyard Gardener web site: http://cals.arizona.edu/yavapai/anr/hort/byg/.

Additional Resources

Why Do Many Reasonable People Doubt Science?
National Geographic Magazine, March 2015


Horticultural Myths
Dr. Linda Chalker-Scott, Washington State University


Cooperative Extension Publications
University of Arizona College of Agriculture and Life Sciences


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Arizona Cooperative Extension
Yavapai County
840 Rodeo Dr. #C
Prescott, AZ 86305
(928) 445-6590
Last Updated: June 10, 2015
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