Preparing To Dig

Properly inverted plants will form a uniform, fluffy, well-aerated windrow with few pods touching the soil.

peanut harvestWhen to dig peanuts is one of the most important decisions growers make each year. The hull-scrape method of determining peanut maturity is an accurate way of judging when to harvest. County Extension agents routinely run crop maturity checks using the peanut profile board in the late season to determine the crop’s progress and potential days to digging. Using this method is more accurate than simply going by days after planting as crop conditions can greatly affect maturity.

Pest management, particularly an effective weed control program, makes harvesting easier, reduces weed pressure and lessens soil compaction. Use tillage or herbicide treatments to suppress grass and other weeds along field borders and at the ends of peanut rows.

When vegetation is present where the digger blades engage the soil, it has a tendency to wrap around the blades, covering the cutting edge. The presence of tough, dead plants at harvest hampers digging even more than the presence of live plants.

Minimize Losses
In a recent study by Clemson University agricultural engineer Kendall Kirk, he found that driving too fast can lead to significant losses when digging peanuts. Conversely, driving too slowly can rip vines apart and increase costs.

According to his study, the optimal ground speed for digging Virginia peanuts is 2-2.5 miles per hour. For each mile per hour above that target speed, digging losses increased 200 pounds per acre.

Kirk also says growers should synchronize the speed of their digger’s shaker chain, or conveyor belt, to their ground speed. If driving 2 miles per hour, for example, the conveyor belt should be set to a speed of around 2 miles per hour. A conveyor belt running about 20 percent faster than ground speed can result in yield loss of 100 to 200 pounds per acre, he says.

Pre-Digging Inspection
Before a speed can be selected, a thorough inspection of the equipment is a must. Inspect the digger-inverter for broken, bent or missing parts before making adjustments. Make sure the front tool bar is level with the tractor. Stand at the rear of the machine with the implement raised and sight the top of the tool bar with the top of the rear axle.

For accuracy, first be sure the rear tractor tires are inflated to the same pressure. If the tool bar is not parallel to the tractor axle, level the digger by adjusting the lift arm.

Next, inspect the blades. A well-adjusted digger will have sharp, flat-running blades set to clip taproots just below the pod zone where the taproot starts branching. Blades should run level, with a slight forward pitch to lift plants into the shaker. This adjustment can be accomplished best on a flat surface.

Excessive pitch of the digger blades may result in soil and pods being carried forward by the blade before being freed by the cutting edge. Such pods are usually lost. Dull blades cause most digging losses because they fail to cleanly cut the taproot and may drag roots or pods, dislodging the pods from the plant.

Set Up For Good Drying
preharvest tipsAfter plants pass over the digger blades, they are transferred onto the shaking conveyer. The shaking conveyer should be set at a depth at which it picks up vines with its teeth just clearing the soil. Check the conveyer chain speed and depth. The chain speed should be set to avoid a pileup of vines ahead of the pickup point and allow a smooth flow of vines through the digger-inverter.

In the field, notice the shaking action. It should be enough to remove soil from the vines. More aggressive shaking is needed where soil clings to pods, roots and stems. The amount of shaking can be changed by adjusting knocker wheels up or down.
As vines exit the shaking conveyer, they engage the inversion wheels and rods.

These rods are factory set; however, they will change position with use. Adjust the inversion rods before going to the field by placing the digger on a level surface and setting them according to the operator’s manual. Properly inverted peanut plants will form a uniform, fluffy, well-aerated windrow with very few peanut pods touching the soil.

For more information on harvesting equipment, consult your equipment owner’s manual or University of Georgia Extension publication: Peanut Digger And Combine Efficiency at

Related Articles

Quick Links

E-News Sign-Up

Connect With Peanut Grower