Cultivators are attachments for tractors that are used for shaking up and loosening the soil. It is used before planting the seeds. But it is also used after the crop starts growing for removing weeds, and letting air percolate in the soil. It has several thick blades attached to it. These blades are like flat strips of curved iron. There are wheels behind to allow the implement move forward along with tractor. Used and new cultivator's from John Deere, Black & Decker, Ryobi, and other popular brands.