The biopolymer Agar Agar, derived from red algea belonging to Rhodophaceae, was tried as a gel soil conditioner. Four greenhouse ex-periments were conducted for this purpose during the period from 1992 to 1994. Results obtained in this study show that seed soaking method could have a promising effect, as: 1: Soaking wheat seeds in Agar solution of 0.2 % significantly in-creased dry weight of plants grown on sandy soils by about 73 % over that obtained from control. A significant considerable enhancement ef-fect for its combination with the three microelements Fe, Mn and Zn at 0.2% of each in chelated form was obtained (129% over control), while the response to these nutrients alone was little. However, there was a relatively slight response to either Agar, micronutrients or their combina-tion in clayey soil. 2: Soaking cotton seeds in Agar solution of 0.2 % significantly in-creased the response of seed cotton yield to N fertilizer in clayey soil. 3: Soaking wheat seeds in Agar solution of 0.1% increased the ef-ficiency of the biofertilizer Cerealin with wheat plants grown on sandy and calcareous soils, as their dry weight increased by 18% and 25% re-spectively over that obtained from Cerealin alone. On the other hand, application of Agar solution to a calcareous soil as anticrusting agent at the rate equivalent to 0.025 % of soil weight, slightly improved the yield of sudan grass. Increasing such rate to 0.05% depressed the yield, indicating that these rates were much higher than that should be used with Agar, a result of economical importance.