Background and Purpose
Recently, school gardens have begun to move from niche to norm as a strategy to promote public health (Severson, 2010; Otterman, 2010).  However, despite growing interest, few studies have examined the effects of gardens on children’s health or health behaviors.  Evidence suggests that gardens may positively influence children’s diet-related outcomes such as vegetable consumption, vegetable knowledge (Morris, Briggs & Zidenberg-Cherr, 2002), willingness to taste vegetables (Morris, Neustadter & Zidenberg-Cherr, 2001; Morris, Briggs & Zidenberg-Cherr, 2002) but studies of gardens’ effects on children’s physical activity (PA) are virtually nonexistent.

Despite the dearth of research examining school gardens and PA, the influence of school gardens on children’s PA merits study for four reasons.  First, preliminary evidence suggests that school gardens have the potential to influence PA (Hermann et al., 2006) and gardening has been linked to PA among adults (Twiss et al., 2003). Second, we know that time spent outdoors is a positive and consistent predictor of PA among children (Ferreira, van der Horst, Wendel-Vox, van Lenthe & Brug, 2006; Sallis, Prochaska & Taylor, 2000).  Thus, one strategy to increase PA is to increase time outdoors, enhance children’s desire to be outdoors, and thereby compete with the “draw” of indoor activities such as TV and computers.  A third argument for gardening as a means to increase PA is that there may be carry-over effects from one context to another — in this case, from school to home.  After participating in a community gardening program in San Bernardino, California, the number of students who gardened at home increased by 20% (Twiss et al., 2003).  A fourth argument for gardening as a strategy to increase youth PA concerns the initiation of long-term health-related habits. Children and youth in this country are not achieving recommended levels of PA (Pate, Freedson, Sallis et al. 2002).  Among children ages 6-11, only 42% achieve the recommended 1 hour of PA per day (Troiano et al, 2007).  Consistent with the life course perspective, empirical evidence suggests that life-long habits, including those related to food and PA (DiNubile, 1993), are established early (Elder 1998; Wethington, 2005).  Introducing children to gardening may help to shift them from a life course trajectory of sedentary activities toward a positive trajectory of gardening and healthy habits.

Objectives
The objectives of this study are to examine:

1. the effects of school gardens on children’s time spent outdoors and physical activity levels during the school day
2. the effects of school gardens on children’s general activity and sedentary behavior patterns over time
3. among children in the intervention group, differences in activity and movement patterns while participating in an outdoor, garden-based lesson compared to while participating in an indoor, classroom lesson.

Methods
In a randomized controlled trial, this 2-year study examined the effects of a school garden intervention on elementary school children's time spent outdoors and physical activity.  Eight low-income New York State schools were randomly assigned to receive school gardens or to serve as wait-list control schools that received gardens at the end of the data collection period. Physical activity was operationalized with three measures.  Actigraph GT3X+ accelerometers worn during the school day for three days at each of four waves of data collection indicated children's levels of vigorous, moderate, and light physical activity as well as sedentary activity.  Lux measures from the accelerometers provided a measure of children's time spent outdoors.  The GEMS Activity Questionnaire (GAQ) (Treuth et al., 2003) documented changes in overall physical activity behaviors over the 2-year period.  Lastly, the PARAGON direct observation measure (Myers & Wells, under review) was used to characterize the postures and movement associated with indoor versus outdoor learning.

Results
Lux readings from the accelerometers indicate that children in the garden intervention group showed an increase in the amount of time spent outdoors during the school day.  In addition, accelerometry results indicate the intervention group increased proportion of time spent in moderate physical activity (MPA) and moderate to vigorous physical activity (MVPA) compared to pre-garden baseline and to the non-garden control group.  Results from the GAQ suggest that over time, children in the garden intervention are less sedentary in their overall activities than the control group children.  Lastly, direct observation data suggest that while participating in a garden-based outdoor lesson, children engage in less sitting and in more walking and standing than while participating in an indoor lesson in the classroom.

Conclusions
School gardens appear to be a potent intervention to increase children’s time spent outdoors as well as the proportion of time spent in MVPA during the school day.  Gardens may also contribute to reduction of overall sedentary activities.  Lessons delivered in the garden are associated with more movement than are indoor lessons.

Implications for Practice and Policy
This study provides evidence that school gardens should move from niche to norm in schools throughout the United States, as another strategy in our toolkit to increase physical activity.

References

1. DiNubile, N. (1993). Youth fitness—Problems and solutions. PrevMed 22:589–594.
2. Elder, G.H. (1998). The life course and human development. Chapter 16. In: W. Damon and R.M. Lerner (Eds.) Handbook of Child Psychology. Vol1: Theoretical Models of Human Development. NY: J. Wiley & Sons, Inc.
3. Ferreira, I., et al. (2006). Environmental correlates of physical activity in youth -- a review and update. Obesity Reviews, 8, 129-154.
4. Hermann, J.R., et al. (2006).  After-school gardening improves children’s reported vegetable intake and physical activity. JNEB, 38: 201-202. 
5. Morris, J.L., et al., (2002). Development and evaluation of a garden-enhanced nutrition education curriculum for elementary schoolchildren. Journal Child Nutrition Management, 2 (Fall 2002).
6. Morris, J. L., et al.(2001). First-grade gardeners more likely to taste vegetables. California Agriculture, 55(1), 43-46.
7. Myers, E.M. & Wells ,N.M. (under review).  Children’s physical activity while gardening.
8. Otterman, S. (2010.  Turning Asphalt into Edible Education.  NYT, October 19, 2010.
9. Pate, R.R., et al. (2002).  Compliance with physical activity guidelines: prevalence in a population of children and youth.  Annals of Epidemiology, 12, 303-308
10. Sallis, J. F., et al. (2000). A review of correlates of physical activity of children and adolescents. MSSE, 32(5), 963-975.
11. Severson, K. (2010).  School adds weeding to reading and writing.  NYT, January 19, 2010, p. D3. 
12. Treuth, M.S., et al. (2003).  Validity and reliability of activity measures in African-American Girls for GEMS.  MSSE, 35 (3), 532 – 539.
13. Troiano, R.P., et al. (2008).  Physical activity in the United States measured by accelerometer.  MSSE, 40 (1), 181-188.
14. Trost, S.G., et al.(1998). Validity of the computer science and application (CSA) activity monitor in children.  MSSE, 1998, 30 (4), 629-633.
15. Twiss, J., et al (2003).  Community Gardens AJPH, 93 (9), 1435-1438.
16. Wethington, E. (2005). An overview of the life course perspective: Implications for health and nutrition. JNEB, 37 (3), 115-120.

Support / Funding Source
This research was supported by The Robert Wood Johnson Foundation through its Active Living Research Program (ALR); The U.S. Department of Agriculture, Food & Nutrition Service (FNS), People’s Garden pilot program; The Atkinson Center for a Sustainable Future.