A seed firmer for use on a seed boot having a guide plate with a rear edge may include an elongated main portion having a mount end for mounting to the boot and a free end extending away from the boot. The main portion may have broad faces and narrow sides extending between the broad faces. The firmer may have a guide portion positioned at a medial location on the guide portion between the ends. The guide portion may have a thin, planar character that protrudes from the main portion in a plane that is oriented generally perpendicular to a plane of one broad face. The guide portion may have a peripheral edge with a substantially linear section and an arcuate section, and the substantially linear section may be positionable adjacent to the guide plate when the main portion is mounted on the boot.
