Midseason Checkup

02:20AM Apr 26, 2014
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How to pinpoint and remedy planter problems

There’s a logical process to identifying mid-season planter problems that starts with getting your knees and hands dirty."I call it ground truthing," says Chris Hartter, product support manager for Precision Planting. "Our 20/20 seed monitors are incredibly accurate at diagnosing problems, but getting out of the tractor cab and digging is still the best way to diagnose planter problems."
In-furrow evidence often indicates how to correct planter problems. On planters with seed meters equipped with finger units, doubles suggest worn seed brushes or finger-unit backing plates. Skips hint of damage to finger springs or the finger mechanism itself. An erratic mix of skips and doubles points to a damaged seed-delivery belt or worn drive pegs/teeth on the plastic wheel that drives that belt.
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The drive pegs on seed belt drive wheels in finger-units can wear thin and hook, causing the belt to jerk and lead to inaccurate seed metering.

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A piece of seed bag "rip strip," a seed bag string or other debris can interfere with accurate metering that shows up as low population on the seed monitor and in the furrow.


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Worn areas alongside the lower seed-delivery belt idler in finger units can disrupt accurate seed delivery. 

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A midseason check of a seed meter on a test stand can usually pinpoint why the unit is planting inaccurately.


On air planters, skips and doubles can often be corrected by adjusting the air system. On vacuum planters, skips hint the vacuum is inadequate to hold seeds to the seed plate. Doubles suggest excess vacuum is holding too many seeds against the plate. 

Simple adjustments. On planters that use air pressure to hold seeds against the seed plate, similar diagnostics apply.

"Skips often mean the air pressure is too low, and doubles mean the air pressure is too high on our planters," says Daryl Cress, service manager, Great Plains Manufacturing. "If you see skips, increase the air pressure. If you see doubles, decrease it."

Loose or worn drive chains can also cause seed monitors to vibrate. After rainy spells, minor rust in the drive chains on ground-drive transmissions can cause jerks that knock seeds off disks in air planters, causing erratic population. Hydraulically driven planters have fewer drive chains but are still susceptible to drive-chain problems.

"If the chain between the hydraulic drive motor and the drillshaft has kinks or is loose, it can jump, and that shows up as erratic population on the seed monitor," says Eldon Schans, a 20-plus-year technician at Greenmark Equipment, Holland, Mich. 

The hydraulic-drive motors can cause seed monitors to sound-off in cabs. Most hydraulic-drive motors are controlled by pulse width modulation (PWM) valves attached to the motors, which are sensitive to contamination.

"If a hydraulically driven planter keeps dropping seeds when the planter is raised, it’s often because debris is caught in the PWM valve and letting oil keep the hydraulic motor turning when it shouldn’t be," Schans says. "I unscrew the cartridge and use contact cleaner to rinse it, which usually fixes the problem."

If individual rows are planting inaccurately, Hartter recommends switching components between rows to diagnose the problem. 

"If the problem stays with the row and doesn’t follow the seed meter or seed tube sensor, then check the [seed monitor] wiring to that row," Hartter says. "Be suspicious of a wire pinched in the parallel linkages or in the hinge of a folding planter."

If the problem follows the component to another row, look for something as simple as a seed bag tag or other debris fouling the seed-delivery mechanism in the meter.

Component wear might also contribute to midseason problems. Finger-unit springs or seed-delivery belts break. Seed brushes fray. "Knock-out" devices that are designed to clean seed tips and debris from the holes in plates wear beyond design tolerances.

That’s why it’s beneficial during rain delays to open each seed meter and check all components for wear and seed-treatment buildup. 

"Seed treatments get stickier on hot, humid days," Cress says. "Clean off accumulations of treatment on brushes and disks in the meter, use a bottle brush to clean the seed sensor eye in the tube and use more talc to minimize buildup."