Purpose and Use
Rototillers are used to break up compacted topsoil and mix in soil amendments such as fertilizer, compost and peat moss. There are two basic types manufactured, the front tine and the rear tine. Rear tine models are easier to use and cost considerably more. They require little physical effort other than walking and guiding. The machine is supported and driven by wheels, and the tine mechanism lowers into the soil. Front tine models are more difficult to use. The weight of the machine is partially borne by the user and considerable effort is required to guide it. Either model will do the job efficiently, turning soil to a depth of 6 to 8 inches or more. Some rear tine models have attachments available for furrowing and seeding.
Regardless of type, rototillers employ a number of spinning blades called tines. The tines have the ends bent in and act as both blades and scoops. As the tines spin, the blades dig into the soil and scoop it up, bringing it to the surface. This action is repeated over and over, cutting and mixing the topsoil to a coarse growing medium. It is this same action that is used to mix amendments into the topsoil. The area to be amended is first tilled until it is finely ground. The amendments are spread over the tilled soil and the tiller is employed to mix them in. Several passes in different directions ensure even and thorough mixing.
Engine and Transmission
On front tine models, the engine serves only as a source of power for turning the tines. Power is transferred from the engine to the shaft the tines are mounted on by means of a belt or chain. The speed of the engine shaft is reduced using pulleys of different sizes. On rear tine models, the machine is self-propelled and a transmission is used to transfer some of the engine's power to the drive wheels, at the same time the tines are made to spin. The rear wheel height is adjustable, which sets the depth the tines will sink into the soil. Better rear tine models have different gear settings that drive the machine forward or reverse at various speeds, independent of the spinning tines.
Mechanical attachments for rear tine tillers make them useful for field work. Furrowing blades dig a furrow in the tilled soil for seeds, which are placed into the furrow using a disk seeder. The disk seeder has various-sized disks for different size seeds. The holes may be spaced to allow for different planting distances. It is the furrow that sets the depth of the seeds. After the seeds are placed in the furrow, the furrow is covered by yet another blade. These attachments are seldom used in small, urban gardens, but have widespread use in market gardening, where large garden plots are grown.