關鍵字： 極有效水、緩衝水、水分總計 。

　　Five organic media, spent golden mushroom compost (GM), peat moss (PM), rice hull (RH), sugarcane compost (SC), and spent Shitake mushroom compost (SM), were used to grow Impatiens walleriana and Begonia semperflorens in 15 cm pots for 6 months. As the planting period increased, soil moisture decreased less in magnitude when water tension of the media exceeded 10 kPa. Means of total water content and easily available water of the five tested media did not reach a favorable level before use. Unless for rice hull, water buffering capability of the other four media was around 5%, but all of them reached favorable level except for Shitake mushroom compost after used for six months. In comparison of organic media used before and after six months, the available water of all media increased. Shitake mushroom compost was the lowest and the rice hull was highest. In the control pots without plants, the trend of available water increased. Therefore, the primary factors on physical properties were the media themselves and the placing period of media.

Key words: easily available water, water buffer capacity, water content .