Growers report that plants on gravel bed surfaces require more frequent irrigation compared to plastic surfaces. The objective of Expt. 1 was to determine if bed surface type influenced container environment and plant growth of azalea and Japanese holly plants on plastic- or gravel-covered beds. Measurements included bed, substrate, and plant canopy temperatures; evapotranspiration (ET), stem water potential, and plant widths also were determined. The objective of Expt. 2 was to determine the amount of water retained following irrigation and drainage for four pre-irrigation substrate water contents (230%, 208%, 185%, 162%; mass basis) on gravel or plastic bed surfaces. Containers on plastic or gravel beds were irrigated, drained for 1 hour, and the amount of water retained in the container substrate was determined. In Expt. 1, plastic bed surface temperatures (0730 to 1930 hr) were higher than for gravel. Container substrate temperatures on plastic were 1°C higher than gravel from 2300 to 0400 hr with no temperature differences from 0500 to 2300 hr. There were no treatment differences for other characteristics. In Expt. 2, containers on plastic retained 21%, 15%, 23%, and 16% more water than on gravel for the 230%, 208%, 185%, 162% pre-irrigation water content treatments, respectively. When containers are seated on plastic, the bottom drainage hole is sealed resulting in more water retention compared to gravel.