Model (Scale 1:4) of Martin's seven-tine cultivator, No. 1 size, embodying patent of 1828

The grubber or cultivator belongs to the Harrow class of implements in as much as it pulverises and stirs the soil without reversing its surface as does the plough. Cultivators are generally of heavier construction than harrows, and are therefore capable of greater working depth. In general it may be said that the cultivator does the rough work of breaking up the soil after he plough while the more superficial work of stirring is done by the harrow; under certain circumstances the cultivator may be used in place of the plough.

A primitive type of cultivator was used by the Ancient Romans, and similar implements, exhibiting a gradual transition from the harrow to the cultivator, appear to have been known to the more progressive British farmers during the 18th century. It was not until the 19th century when Sir John Sinclair in 1811 introduced an implement then known as a scarifier, and later as the old Scotch Grubber, that the development and use of this class of implement became,e wide spread.

The distinguishing feature in Martin's cultivator patented in 1828, was the sliding tine held by a strong spring. This was to combine the advantages of strong rigid tines which remain at the same depth an proper angle, with those of sprint steel tines which vibrate and pulverise the soil well. The tine frame could be adjusted in relation to the wheel ale by means of the near side handle. This lever also controlled the working depth of the tines. The off side lever was used for raising the tines when turning.