Cultivators and tillers both use metal blades to dig into the ground. The size of the job you plan to tackle will determine whether you need a cultivator or a tiller.
A cultivator is good for loosening the soil in an existing planting area, weeding the area during the growing season or mixing compost into the soil. Cultivators are smaller and easier to maneuver than tillers. You can find cultivators in gasoline-powered, cordless and corded electric-powered models. Some gasoline-powered cultivators will crank with an optional powered device that you purchase separately, eliminating the need for using a pull cord.
A tiller is a gasoline-powered machine with a greater working width than a cultivator, making it a good option for heavier jobs. Tillers are more powerful than cultivators and have larger, heavy-duty tines that work the soil.
Front-tine tillers can perform general garden maintenance such as weeding, soil preparation and composting in small or medium gardens. A small tiller like this has tines that help move the machine while digging into the soil. Some have the option to engage the tines in forward or reverse.
Rear-tine tillers have engine-driven wheels. These machines are best for larger planting areas. They can have forward-rotating tines that perform well in existing beds for cultivating, weeding and working in compost or old vegetation. Rear-tine tillers can also have counter-rotating tines that turn in the opposite direction of the wheels. Counter-rotating tines have more torque for breaking up new ground and can dig deeper into the soil. Some rear-tine tillers offer dual-rotating tines so you can select forward or counter rotation to match the work you need to do.
*From Marc M.