1. Apparatus for sowing seed in buried condition at a substantially uniform and selected depth below the ground surface and in zig-zag row pattern, said apparatus comprising, in combination: a frame adapted to be moved over the ground surface along a selected path; means for supporting said frame at a selected level above the ground surface as it is moved along said path; a plurality of teeth carried by said frame and depending therefrom to distances greater than said selected level whereby tip portions of said teeth project into the ground, each of said teeth having a rearwardly directed seed discharge opening in its tip portion and all of said seed discharge opening being located in a substantially common horizontal plane located at said selected depth at which seed is to be buried, each tooth also having a seed-guiding channel therein leading downwardly to a corresponding seed discharge opening; seed supply means carried by said frame above said teeth and including seed guiding means communicating with upper portions of said channels Whereby seed flows by gravity from said seed supply means, through said channels and out through said seed discharge openings at said selected depth; and drive means for moving said teeth back and for transverse to said path as said frame is moved along such path so that (1) seed is sown in zig-zag row pattern at said selected depth and (2) the ground soil automatically fills in and buries seed at said selected depth.

6. A harrow comprising a frame, a plurality of transversely extending teeth carrying beams provided in spaced generally parallel relationship with one another and movably supported by the frame, each of said beams carrying depending teeth, drive means supported by the frame and operatively connected to said beams for transversely reciprocating said beams, said harrow being movable in a direction so as to define a leading beam which is forwardmost of said beams and a trailing beam disposed rearwardly of said forwardmost beam, the teeth of said trailing beam each including means defining a channel extending longitudinally of the associated tooth, a seed supply supported by said frame and being connected with an upper portion of each of said channels, each of said channels defining an outlet at the lower end thereof for sowing seeds, a rubbing plate being supported by said trailing beam, said plate being located above the outlets of said channels, said rubbing plate being provided with teeth on the rear side thereof.

8. A method of sowing seeds comprising feeding seeds downwardly by gravity through channels associated with a plurality of teeth, said channels terminating in rearwardly facing seed outlets at their lower ends and being positioned beneath the surface of the ground, maintaining said seed outlets at a selected depth below the ground surface, moving said teeth through the ground in a forward direction while feeding said seeds downwardly by gravity, and simultaneously moving said teeth back and forth in a direction transverse to said forward direction to thereby sow seeds into the ground beneath the surface thereof in a generally zig-zag pattern and at said selected depth.