A main concern for producers of container grown plants is optimal water relations. Most problems occur because of poor physical properties of the media, container design, and poor irrigation practices.
The purposes of this study were (1) to determine the effects of container design on physical parameters of container media of differing bulk density and (2) to determine the effects of various edaphic parameters on the functioning of a new moisture controlling device (MCD), designed to optimize plant-media water relations.
Four container designs and four media were tested to determine the following factors: total porosity, water-holding capacity, air space, and bulk density. As bulk density increased for the four media, total porosity decreased. An experimental prototype container with a fabric bottom, placed on a column of sand, resulted in removal of the perched water table, therefore increasing air space in a given medium.
A newly developed moisture controlling device (MCD) was tested under laboratory and greenhouse conditions. The MCD was influenced by different media, soluble salt levels, and different moisture levels. The MCD responded well over the range of moisture found in container media and should prove to be useful under conditions where other devices fail. Water utilization of container grown Coleus was monitored using the MCD and it was found that media was the dominant factor in the time to wilting of these plants under greenhouse conditions. Milliampere readings on the MCD were highly correlated with percent water holding capacity remaining in a container, though influenced by soluble salt level and media
