The aim of this paper is to utilize the horizontal metering disc device to perform planting of sprouting tubers operation with minimum sprout damage, minimum tubers void, minimum tubers double and in proper time. The Horizontal metering mechanism was investigated as a new system to fulfill planting potato tuber with previously grown buds (Sprouts). The construction features of the developed potato planter (Horizontal Metering Mechanism) prototype are mainly: tuber hopper; chamber room; circle tray with feeding cups; the vibration mechanism and power transmission system from the land wheel to the rod of metering device. The theoretical investigation of the developed mechanisms was investigated. The relation between horizontal disc and tuber diameters was theoretically found. The diagram among engineering of feeding disc device parameters and tuber diameters were illustrated. The result of tuber void ratio versus land wheel speed (rpm) was 0% for time equal to four cycle time of land wheel. The tuber out percentage was evaluated at two categories of tuber samples 30-50, 50-80g. The general trend of this relationship is the percentage of tuber out decreased with the increase of land wheel speed and decrease of feeding cups diameter. The maximum value of the sprout damage percentage (Ts,%) is 26.1% at land wheel speed of 14rpm. and feeding cups diameter of 8cm recorded for category 50-80g, and the minimum value of (Ts,%) was 11.5% at Land wheel speed of 10 rpm. and feeding cups diameter of 6cm recorded for category 30-50g. From above results, May be recommend that the disc metering mechanism need more improve.