Differences Between Grass and Grain Drills
GRAIN DRILLS: Grain drills are configured with either a single seed box for "Flowable seeds, large" or may also have a second box for small "Flowable seeds (small)". Generally, grain drills will have a larger box capacity and therefore can handle bigger plantings.
GRASS DRILLS: Grass drills are generally configured with two or more boxes to meter and distribute a variety of species. A box for Nonflowable seeds is standard along with a smaller box for Flowable, (small) seeds. In addition, a multipurpose grass drill can be manufactured by adding a Flowable seed, (large) to a two box grass drill. When this is done the third box is a smaller capacity so as not to effect the straight line seed drop from the seed meters.
Flowable seeds, (large) such as cereal grains, beans, wheat grasses, tall fescue, and smooth brome are metered and distributed through a grain drill which has fluted feed roll meters with either no agitators or a passive agitator to prevent lodging in the bottom of the seed box.
Flowable seeds, (small) such as legumes, some cool season grasses, i.e. timothy and orchard grass, and some forbs are metered and distributed through a seed box that utilizes a small sized fluted feed roll meter.
Nonflowable seeds, such as the prairie grasses, i.e. blue grama, the bluestems, and side oats, which require aggressive agitation and positive feed meters with picker wheels, are distributed through a grass drill that is equipped with these features.