An old or abandoned field that has become overgrown with weeds will, over time become overgrown with rocks as well. Over the passage of time, woodland type weeds begin to dominate over perennial weeds in an abandoned or neglected field, causing the soil to become more acidic. As this happens, rocks begin to rise to the surface of the soil. It's difficult to mow and till if you want to care for the field and bring it back into a productive state. If you have an old hayfield or other neglected field that you need to clear of rocks, renting a rock picker or windrower will help you get the job done quickly.
Assess the condition of your field. Walk over the surface, surveying the field and keeping a record of the rough number of large stones and rocks you see scattered throughout the field. Note the average size of the rocks in your field. Mark off the center of your field with orange cones or flags.
Rent a rock picker, windrower or bulldozer with a rock rake attached to it to clear your field of rocks. Alternatively, you may choose to hire someone to use one of these machines to clear your field of rocks for you.
Review the rock size limitations for the specific rock picker or windrower you are considering renting. Many rock pickers can handle rocks up to 27 inches in diameter.
Starting in the northwest corner of your field, run the picker or windrower at slow speeds of about 2 miles per hour in rows over your field. Once the hopper on the rock picker or windrower fills to capacity, lift the picker or rake off the surface of the ground and drive slowly to the center of your field. Dump the collected rocks into a pile in the center of the field.
Continue driving over the field until the entire surface has been cleared of rocks that you've gathered into a large pile in the center of your field. Return the rock picker and rent a bulldozer or other piece of heavy machinery to remove the rocks from your field and take them to a local salvage or junk yard. Or, use the rocks to mark off the perimeter of your field, if desired.