Abstract: The Co-Compostage (CC) of Palm (Poenix dactylifera L.) Fiber (PF) and Sewage Sludge (SS) at volume rate (1PF/1SS), mixed with Top Soil (TS) have been used as a substrate for cucumber cultivated in soilless crop system. Five substrates with volume ratio T (CC-TS) were tested: T (10-0), T (9-1), T (8-2), T (7-3) and T (6-4). They were compared to peat in nursery and to TS in Cucumis sativus L. crop production. Total porosity, bulk density, moisture content, rate of drainage, pH and electritical conductivity of T (8-2) and T (7-3) were relatively favorable for plant growth. After 45 days of growth and in comparison to peat, T (9-1), T (8-2) and T (7-3) gave the best parameters of root development: volume, architecture, length, number, best seedling growth and a positive correlation (R = 0.751) between root and shoot dry matter. After 120 days, cucumber attained the best root development under T (8-2) and T (7-3). Fruits production of these substrates was 40% higher than those of the control.