Ridges are usually built 6 to 8 inches high to allow for weathering and settling. By spring they will usually be 4 to 6 inches high. Ridges are usually built when the crop is 12 to 18 inches high. Since there is only a short time span when ridges may be formed before the crop is too large, cultivation may become the critical factor for large operators. Ridges are seldom used with rows narrower than 30 inches.
Wider rows allow the ridges to be higher or less peaked.
Ridges that are nearly flat, or slightly rounded, and fairly wide present less problems with holding planters on ridges. Wider rows also allow the use of the wide widths of combine tires more commonly used on the larger machines. Ridges are sometimes built after harvest. This works best when there is very little residue on the surface, such as after removal of a silage crop. Heavy residue, such as corn or milo stalks, should be shredded.