Understanding the mechanical actions of weeding with a spring-tine harrow at different tine settings is necessary to achieve optimal weed control. The mechanical actions of a tine harrow in two different soils at two different locations on the harrow were investigated, pointing out the effects of varied implement settings and operational conditions on the tine weeding performance. A commercially available flexible harrow tine was investigated in sandy and sandy clay loam soils. The tine was pulled in soil bins without plants in order to avoid biological variances. Tine movements and forces acting on the tine were measured with strain gauges and analysed as the mean backward and upward tine torsion, the variation of the tine location around the mean position in sideward and upward direction and the properties of the vibrational frequency in sideward and upward direction during working. In addition, a high-speed camera was used to provide visible description of tine mechanical actions.