You'll get better results by also plowing. The disc will help cut the soil up which in turn will give you easier plowing. The deeper you can loosen the soil, the better it'll be for your planting. You may get by though by discing the heck out of the area. If planting clovers/grasses, you don't need inches of loosen soil. It helps, but could get by. Disc it till it's black and loose 3-4 iches and see what happens.Taz