A cultivator is a type of farm implement used for secondary tillage. It stirs and pulverize the soil, either before planting to aerate the soil and prepare a smooth, loose seedbed or after the crop has begun growing (to kill weeds—controlled disturbance of the topsoil close to the crop plants kills the surrounding weeds by uprooting them, burying their leaves to disrupt their photosynthesis, or a combination of both). These are designed to disturb the soil in careful patterns, sparing the crop plants but disrupting the weeds.