Seed firmer

1. A seed firmer for pressing seeds into soil during planting, the seed firmer comprising:

a mount for attachment to a row unit of a planting machine; and

an arm defining a ground-facing surface having at least one point of contact with the ground, including a rearmost ground contact point with respect to a direction of forward travel during planting operation,

wherein the ground-facing surface has a transition section directly trailing a rearmost ground contact point, the transition section extending upwardly from the rearmost ground contact point with a radius no less than 25 mm.

2. The seed firmer of claim 1 , wherein the rearmost ground contact point is the single lowest point of the ground-facing surface.

3. The seed firmer of claim 1 , wherein the ground-facing surface includes a flat section forward of the rearmost ground contact point.

4. The seed firmer of claim 1 , wherein the transition section extends upwardly from the rearmost ground contact point with a radius no less than 40 mm.

5. The seed firmer of claim 1 , wherein the transition section extends upwardly from the rearmost ground contact point with a radius no less than 60 mm.

6. The seed firmer of claim 1 , wherein the mount includes a linkage having two parallel intermediate links rotatably coupled to the arm to provide vertical travel of the arm without changing the orientation of the arm.

7. The seed firmer of claim 6 , wherein the mount further includes a first spring engaged with the linkage to bias the arm in a downward direction toward the ground.

8. The seed firmer of claim 1 , wherein the arm includes an overhang spaced rearward and above the rearmost ground contact point.

9. The seed firmer of claim 1 , wherein the transition section extends at least 3 mm above the rearmost ground contact point.