What Have Plants Done for You Lately?
 Facts about how gardening and plants improve our quality of life

Human Issues in Horticulture (HIH) is a branch of horticultural science that seeks to understand the role plants play in our quality of life. Most of the data confirms what is obvious to anyone who works with and loves plants: Being around them makes people feel good. But more importantly, by highlighting and measuring the impact of plants on specific environmental conditions and human behaviors, the research throws light on how crucial the presence of plants and natural settings are to our health and well-being.

With the hard data HIH studies provide about the positive influence of plants, planners can justify including plants in the exterior and interior design of hospitals, shopping areas, public housing…and, of course, schools! And, it can help you rally support for your plant-based teaching program.

Here are some of the ways that plants make a difference in our lives. These “factoids” were gleaned from reports of HIH research done over the last several decades.

In urban areas, plants:

  • Reduce heating and cooling costs
  • Reduce erosion
  • Filter pollutants
  • Reduce carbon dioxide buildup

(Coder: 1996)


Indoors, plants:

  • Remove toxins that threaten human health, including formaldehyde, toluene, and benzene, from the air (Wolverton et al., 1984; 1989; Darlington et al., 2001; Wood et al., 2002)
  • Help keep humidity at comfortable levels (Lohr 1992a, 1992b)
  • Reduce airborne dust (Lohr and Pearson-Mims, 1996)
  • Reduce airborne mold spores and microbes (Wolverton and Wolverton, 1993)

According to the book How to Grow Fresh Air, two houseplants in 14- to 16-inch pots can “clean” the air in a typical 100-square-foot interior space!


In Communities:

  • Community gardeners, more control group members, tend to regard their neighbors as friendly (Blair et al. 1991).
  • Community gardens promote neighborhood “togetherness,” trust, and reduced racial discrimination (Feenstra, et al. 1999).
  • In public housing, greened landscapes promote healthy social functioning, better interpersonal relations, less verbal and physical aggression, and less violence (Kuo et al., 1996).
  • Older adults feel a stronger sense of community when they have access to green outdoor spaces (Kweon et al., 1998).
  • Parents supervise their children better and are less prone to aggression and violence in a green landscape (Taylor, et al., 1998).
  • Green spaces foster activities that promote healthy child development (Coley, et al., 1997; Taylor et al., 1998).
  • Vandalism, litter, graffiti and crime is less common in green landscapes (Kuo and Sullivan, 1996; 2001).
  • Drivers experiencing stress feel relief more quickly when driving through a green landscape than on a road lined with strip malls (Parsons et al., 1998).

For Individuals:

  • People are more relaxed when viewing green landscapes vs. an urban scene (Ulrich and Simons, 1986).
  • The presence of plants in a room increases attention and reduces stress (Lohr, et al., 1996).
  • Students perform better when the view from their room is dominated by plants vs. buildings and pavement (Tennessen and Cimprich, 1995).
  • Gardening for 45 minutes burns as many calories as a 30 minutes of aerobics (Taylor, 1990).
  • In a study comparing the effects of different forms of exercise on bone density, gardening scored second only to weight training (Turner, et al., 2002).
  • Patients in hospitals recover more quickly and experience less pain if their rooms look out onto trees rather than on a building (Ulrich, 1984).
  • Alzheimer’s patients in facilities with landscaped grounds exhibit fewer violent outbursts than those in facilities with hardscape only (Mooney and Nicell, 1992).
  • Children with ADD can concentrate better when they spend time in natural, green settings. The 10% of children with ADHD who do not respond to medication showed significantly reduced symptoms after taking part in green outdoor activities (Taylor et al., 2001).
  • Participants in adult day facilities interact more when taking part in horticultural activities vs. craft projects (Kerrigan and Stevenson, 1997; Predny and Relf, 2000).

In our diets:

  • Community gardens are associated with increased food security and food quality (Butler and Maronek, 2002).
  • Growing your own food can reduce food costs and increase intake of fresh, nutrient-rich vegetables (Blair et al., 1991).
  • Children who participate in youth gardens are more likely to recognize and consume vegetables (Pothukucki and Bickes, 2001).
  • Curriculum combining gardening and nutrition improves student attitudes towards fruit and vegetable snacks (Lineberger, 1999).

In Schools:

  • Self-esteem and attitudes toward school improve when kids take part in garden-based learning (Sheffield, 1992).
  • Improved social skills and behavior are the most prominent benefits to kids reported by gardening teachers nationwide (Demarco, 1999).
  • Garden-based learning has a positive impact on children’s understanding of key life science concepts and their investigative skills (Pranis, 1992).
  • Kids engaged in gardening show significant improvement in environmental attitudes (Skelly, 1997).
  • Children who participate in horticultural activities show more group cohesion than those who did not (Bunn, 1986).
  • Adolescents who participate in horticultural activities show improved interpersonal relationships compared with those who did not. Such improved attitudes carry through into adulthood (Campbell et al., 1997; Skelly and Zajicek, 1998; Waliczek and Zajicek, 1999).
  • People who train to be cooperative extension Master Gardeners report that they stay with the program because it improves self-esteem, offers continued learning opportunities, the chance to help and feel a connection to other people, to feel a sense of purpose, and a way to develop skills for employment (Schrock et al., 2000; Meyer, 1997; Dorn and Relf, 2001)

 

Bibliography/Literature Cited

The primary source for this report:

Relf, Paula Diane, and Virginia I. Lohr. “Human Issues in Horticulture.” HortScience Vol. 38(5): 984-991. This was the primary source.

From this report, the following references were cited:

Blair, D., C.C.Giesecke, and S. Sherman. 1991. A dietary, social, and economic evaluation of the Philadelphia urban gardening project. Journal of Nutrition Education. 23:161-167.

Bunn, D.E. 1986. Group cohesiveness is enhanced as children engage in plant-stimulated discovery activities. Journal of Therapeutic Horticulture. 1:37-43.

Butler, L.M. and D.M. Maronek. 2002. Urban and agricultural communities: Opportunities for common ground. Council Agricultural Science Technology, Ames, IA, Task Force Report. 138.

Campbell, A.N., T.M. Waliczek, J.C., Bradley, J.M. Zajicek, and C.D. Townsend. 1997. The influence of activity -based environmental instruction on high school students' environmental attitudes.

Coder, K.D. 1996. Identified benefits of community trees and forests. 13 Mar. 2003. <http://www.marshalltrees.com/upload/articles_files/art_31attached_file.pdf>

Coley, R.L., F.E. Kuo, and W.C. Sullivan. 1997. Where does community grow? The social context created by nature in urban public housing. Environmental Behavior 29:468-492.

Darlington, A.B., J.F. Dat, and M.A. Dixon. 2001.The biofiltration of indoor air: air flux and temperatures influences the removal of toluene, ethylbenzene, and xylene. Environmental Science Technology 35:240-246.

DeMarco, L. 1999. The factors affecting elementary school teachers' integration of school gardening into the curriculum. Unpublished doctoral dissertation. Virginia Tech University, Blacksburg.

Dorn, S. and P.D. Relf. 2001. Assessing the Virginia Cooperative Extension Master Gardener Coordinator Manual. HortTechnology 11:472-476.

Feenstra, G., S. McGrew, and D.Campbell. 1999. Entrepreneurial community gardens: Growing food, skills, jobs and communities. Agr. Natural Resource Publication 21587. University of California Davis.

Kerrigan, J and N.C. Stevenson. 1997. Behavioral study of youth and elders in an intergenerational horticultural therapy program, p. 141-154. In: S.E. Wells (ed.). Horticultural therapy and the older adult population. Haworth Press, Binghamton, NY.

Kuo, F.E. and W.C. Sullivan. 1996 Do trees strengthen urban communities, reduce domestic violence? Forestry Report. R8-FR 55, Technical Bulletin No. 4. USDA Forest Service Southern Region, Athens, GA.

Kuo, F.E., and W.C. Sullivan. 2001. Environment and crime in the inner city: Does vegetation reduce crime? Environment and Behavior 33:343-367.

Kweon, B.S., W.C. Sullivan, and A. Wiley. 1998. Green common spaces and the social integration of inner-city older adults. Environment and Behavior 30:832-858.

Lineberger, S.E. 1999.The effect of school gardens on children's attitudes and related behaviors regarding fruits and vegetables.<http://aggie-horticulture.tamu.edu/nutrition/research/abstract.html>.

Lohr, V.I., C.H. Peason-Mims, and G.K. Goodwin. 1996. Interior plants may improve worker productivity and reduce stress in a windowless environment. Journal of Environmental Horticulture. 14:97-100.

Meyer, M.H. 1997. Master Gardener Projects -- Making connections .HortTechnology 7:339-344.

Mooney, P.F., and P.L. Nicell. 1992. The importance of exterior environment for Alzheimer's residents: Effective care and risk management. Healthcare Management Forum 5(2): 23-29.

National Gardening Association. “Research Support for Kids’ Gardening,” 2002.

Parsons, R., L.G. Tassinary, R.S. Ulrich, M.R. Hebl, and M. Grossman-Alexander. 1998. The view from the road: Implications for stress recover and immunization. Journal of Environmental Psychology 18:113-140.

Pothukuchi,K., and J. Bickes. 2001. Youth nutrition gardens in Detroit: A report on benefits, potential, and challenges. Wayne State University, Detroit, MI

Predny, M. And P.D. Relf. 2000. Interactions between elderly adults and preschool children in a horticultural therapy research program. HortTechnology 10:64-70.

Schrock, D.S., M. Meyer, P.Ascher, and M. Snyder. 2000. Reasons for becoming involved as a Master Gardener. HortTechnology 10:626-630.

Sheffield, B.K.. 1992. The affective cognitive effects of an interdisciplinary garden-based curriculum on underachieving elementary students. Unpublished doctoral dissertation, University of South Carolina, Columbia.

Skelly, S.M., and J.M. Zajicek. 1997. The effect an interdisciplinary garden program, on the environmental attitudes of elementary school students. HortTechnology 8:579-583.

Taylor, A.F., F.E. Kuo, W.C. Sullivan. Coping With ADD: The Surprising Connection to Green Play Settings. Environment and Behavior, Volume 33, Number 1 (January 2001): 54-77.

Taylor, A.F., A. Wiley, F.E. Kuo, and W.C. Sullivan. 1998. Growing up in the inner city: Green spaces as places to grow. Environment and Behavior, Volume 30, 3-27.

Tennessen, C.M., and B. Cimprich. 1995. Views to nature: Effects on attention. Journal of Environmental Psychology. 15:77-85.

Turner, L., M.A. Bass, L. Ting, and B. Brown. 2002. Influence of Yard Work and Weight Training on Bone Mineral Density Among Older U. S. Women. Journal of Women and Aging 14(3-4): 139-148.

Ulrich, R.S. 1984. View through a window may influence recovery from surgery. Science 224:420-421.

Ulrich, R.S., and R.F. Simons. 1986. Recovery from stress during exposure to everyday outdoor environments. p. 115-122. In: J. Wineman, R. Barnes, and C.Zimring (eds.). The Costs of Not Knowing. Proceedings of 17th Annual Conference of the Environmental Research and Design Association, Washington, D.C.

Waliczek, T.M. and J.M. Zajicek. 1999. School gardening: Improving environmental attitudes of children through hands-on learning. Journal of Environmental Horticulture 17:180-184.

Wolverton, B.C., R.C. McDonald, and E.A. Watkins, Jr. 1987. Foliage plants for removing indoor air pollutants from energy efficient homes. Economic botany 38:224-228.

Wolverton, B.C., and J. Wolverton. 1993. Interior plants: Their influence on airborne microbes and relative humidity levels inside energy-efficient buildings. Research report WES/100/05-93/001, Wolverton Environmental Service, Inc., Picayune, MS.

Wood, R.A., R.L. Orwell, J. Tarran, F. Torpy, and M. Burchett. 2002. Potted-plant/growth media interactions and capacities for removal of volatiles from indoor air. Journal of Horticultural Science and Biotechnology.

Additional Sources:

Plants at Work. “Resources by Building Type.” Case studies and reports of the ways plants improve our lives in the built environment. http://www.plantsatwork.org/.

Pranis, E. 1992. GrowLab curriculum study. National Gardening Association, South Burlington, VT.

Wolverton, B.C. How to Grow Fresh Air. Penguin Books, 1997.

 

 

Back to Activity

Copyright© 2005 National Gardening Association