The most basic type of tilling is simply turning over large portions of soil with a garden spade or shovel. Specialized tilling tools lift soil, flip soil and break clumps of dirt into smaller particles. Tilling not only improves the workability and drainage of soil but also allows the garden to incorporate mulch, compost and fertilizers with native soil. Task-specific tilling tools, called tillers and cultivators, are available as both manually operated hand tools and engine-driven machines.
The term hand tiller generally refers to pronged tools that mount to poles or short, straight handles. The most common type of hand tiller has a metal head of three claw-like prongs, similar in design to a back-scratching tool. To use this type of tiller, the gardener plunges the prongs into the soil and pulls toward his body to move and break soil.
Another common type of hand tiller, often called a hand cultivator, has a head of straight prongs that jut outward at various angles to form a web of sharp points. When plunged into the earth and rotated, the hand cultivator breaks up soil. Like the hand tiller, the hand cultivator mounts either to a short, straight handle for working close to the ground or a long pole for working from a standing position.
The power cultivator shares the arrangement of its tilling blades with the hand tool of the same name. However, unlike the manually-operated hand cultivator, the power cultivator's web-like arrangement of prongs rotates with force supplied by an electric or gas-powered motor. The power cultivator's blades sit at the end of a long, curved body, typically similar in design and appearance to the body of a string trimmer. To use the power cultivator, the gardener holds the tool waist-high, grips its handle and pulls the trigger to activate the prongs' rotation.
Common among both amateur and professional projects, the rotary tiller turns and breaks soil with a set of rotating blades. The rotary tiller drives its blade with a gas-powered motor. Wheels mounted aside the engine allow the machine's operator to push the machine with a waist-high, walk-behind handle. The rotary tiller's set of blades often stretch 2 or 3 feet wide and plunge several inches to more than a foot below the soil's surface. Aside from tractors, rotary tillers are the most expensive tilling tool. However, most tool rental companies keep rotary tillers on hand for hourly or daily rental.