Abstract: A seed drill which will allow seed to be planted at a substantially constant depth regardless of contours and irregularities in the ground surface. The said drill has a tyne pivotally mounted on a frame for angular movement about a substantially horizontal axis transverse to the direction of travel. The lower end of the tyne being adapted to support a ground engaging tool with a seeding boot located rearwardly of the tool whereby the tool is arranged to form a furrow in the ground for seed discharging from the seeding boot. A spring biassing means acts between the tyne and frame for urging the tool into engagement with the ground. The spring biassing means is arranged to exert a biassing force on the tyne for counteracting the resistive force exerted on the tool as the tool traverses the soil whereby to maintain the tool at a substantially constant working depth in the soil.