This rolling dibble drum is custom made to the width of the bed. The points on the drum are spaced for the minimum plant spacing used and when planting the worker uses every mark, every other, etc. and only the rows of interest. The drum is interchangeable with one that simply makes lines down a bed for guiding a pushed seeder like a Planet Junior. There is also a light-weight handle that the drum clips into for manual dibbling; we often use it inside a movable greenhouse. A careful user can create very straight rows.
There are many designs for rolling dibbles. This one, made from 12" schedule 40 PVC pipe, was derived from a design from the University of Wisconsin.
In frame for mounting behind Cub.
Snapped into hand frame
Another, larger version
I am not making these anymore.