An agricultural row unit for planting seeds in a furrow includes an opening tool that cuts a furrow in the soil to be planted, and a gauge wheel that engages the soil to control elevation. A depth control actuator applies a controllable down force to the gauge wheel, and a sidewall compaction sensor extends into sidewalls of the furrow and produces a signal representing the compaction of the soil. A controller supplies the depth control actuator with a control signal representing a down pressure set point to form a furrow having a desired depth. The controller uses the signal representing the compaction of the soil in the sidewalls to determine whether the down pressure set point should be increased or decreased, and supplies the depth control actuator with a control signal when it is determined that the down pressure set point should be increased or decreased.