FNGLA Funds Citrus Research

The Florida Nursery, Growers and Landscape Association (FNGLA) has announced a new research project funded by FNGLA’s Citrus Nursery Division’s predecessor organization – the Florida Citrus Nurserymen’s Association.  FNGLA’s Citrus Nursery Division promotes and represents the business interests of citrus nursery members within Florida’s environmental horticulture industry. 


Dr. Tim Spann, an assistant professor in horticultural sciences at the University of Florida’s Citrus Research and Education Center (CREC), is conducting research in the areas of soil temperature and soil moisture related to nursery tree growth. Spann has recruited two undergraduate students from the Agricultural University in Honduras to assist in the research process.  

The following research is being conducted at citrus nursery sites around the state. The results will be beneficial to all Florida Citrus Nursery operations.   

Soil Temperature
The first part of the research experiment focuses on container media temperature and is one of several steps in an effort to understand the source of variability among trees in a nursery. 

Root temperatures have a tremendous influence on plant growth, primarily through limitation on root growth and water/nutrient uptake when temperatures are too low in winter or too high in summer. The study will examine the effects of root/media temperatures on plant growth under two different day lengths, determine the natural variability that exists in root/media temperature in at least one commercial nursery, and will correlate root/media temperature with plant growth in at least one commercial nursery.

This research will answer the question about the importance of root/media temperature to tree growth in the nursery, what variations exist and will provide data for nurseries to decide whether or not it is worth their investment to alter root/soil temperature.  

Soil Moisture
The second part of the research relates to drought stress and examines the effect of soil and plant water status on liner growth, bud take and bud growth. Currently, most nurseries use overhead irrigation for watering. This method of irrigation is inherently non-uniform and may be made more variable by factors such as close pot spacing and large tree size. Since water is very influential in regulating plant growth, growth of individual trees may be reduced even though that tree never appears to wilt. This study strives to reach a better understanding of drought-induced growth limitations in the commercial citrus nursery. 

This research will be directly applicable to citrus nurseries for understanding the variability in water application that exists in their nurseries and what effect it has on tree growth. Nurseries can more thoroughly examine irrigation scheduling or methods.

For more information about these research studies, please contact Dr. Tim Spann at [email protected].