The experiments reported here measured daily water use by petunias grown in containers in a glasshouse.
Seedlings of 'Single Dreams Pink' and 'Prostrate Easy Wave Pink' were transplanted into plastic containers holding 420, 767, and 1,320ml of a soil-less substrate. Irrigation was controlled via capacitance sensors placed in each size of container with each cultivar. When the average water content in a treatment dropped below 0.4cu m per cubic metre, solenoids opened and 2.4ml of water was delivered to each container.
The daily water use could then be calculated from the number of irrigations per day. Various mathematical models were tested for their ability to predict the daily water use of petunia. 'Days after planting' proved to be a simple and accurate estimate of the influence of plant size.
This could be further refined by including a term for container size.
The influence of the environment was adequately described by monitoring the daily light integral, humidity, and temperature.
The best model accurately predicted the observed fluctuations in daily water use and so could be used to control the irrigation of petunia.
Dr Ken Cockshull, Associate Fellow, Warwick Crop Centre, University of Warwick
Estimating Daily Water Use of Two Petunia Cultivars based on Plant and Environmental Factors by Kim, van Iersel and Burnett (2011). HortScience 46 (9): 1287-1293. Members of the International Society for Horticultural Science can view HortScience from the website www.ishs.org