Accurate Seed Treater

February 22, 2010 09:49 AM


Accuracy, capacity, compact design and the ability to treat seed at night or during rainy weather earned Robbie Williams' seed treater a category win in Farm Journal's "I Built the Best” contest.

The seed treater built by Henderson, Ky., farmer Robbie Williams, his seed-treating partner Nic Womack and several assistants, is noteworthy for its capacity, its compact design, the ability to treat seed at night or during rainy weather and the ability to load either bags, boxes or trucks with treated seed. But its most striking feature is its accuracy—perhaps unprecedented in a farm-scale setup.

The treater—which won first place in the Miscellaneous Category of Farm Journal's I Built the Best Contest--consists of two custom-built cone-bottom seed tanks mounted on a tubular-steel framework. Product tanks for liquid fungicide, insecticide and inoculant are located underneath.

"Mounting the seed tanks overhead, with the equipment for inoculant, fungicide and insecticide underneath, minimizes space requirements,” Williams points out. "It's a much more compact design than you usually find.”

The process of applying chemicals is similar to that used by seed companies. Seed to be treated is transported to a "dry tank” in a custom-built conveyor.

Chemicals and biological products are loaded through inductors—a conventional one for those that come in jugs and a laundry-sink inductor for those packaged in plastic bags—easily accessible from ground-level. From the inductors, treatment materials are transferred to the product tanks by Grainger air-powered diaphragm pumps.

Into the mixing chamber. From the product tanks, treatment materials are metered into the mixing chamber by Cole-Parmer peristaltic pumps. "We chose positive-displacement pumps because they provide more repeatable accuracy,” says Williams.

"We can apply each product separately, or all three together,” says Williams. "We keep the products separate until just before they are applied to the seed.”

After the dry tank is filled with seed, a pneumatic air cylinder controlled by an electric solenoid valve opens a sliding gate in the bottom. The flowing soybeans trigger a microswitch, and inoculant, fungicide and/or insecticide is applied by a Gustafson CS-1700 rotary atomizing head and mixing chamber.

When the flow of seed ends, a microswitch shuts off the flow of product. The treated seed is carried to the output tank by a second conveyor. If the output conveyor stops for any reason, a contactor, salvaged from an old grain dryer, automatically closes the sliding gate in the dry tank, stopping the flow of seed and shutting off the product pumps.

Other fail-safe features are incorporated throughout the system, including overloads on all the motors that shut down the system if any motor begins pulling too much electricity.

Continuous-flow. Because of the capacity of the tanks (each one can hold 100 50-lb. units, or 5,000 lb. of seed) and the speed of the conveyors, an operator can begin treating a batch of seed as the seed is being unloaded from a bag or box and conveyed into the dry tank. While the treated seed accumulates in the output tank, the original bag or box can be moved underneath the output tank, to be re-filled with treated seed. So there are no bottlenecks in the treatment process.

Williams calls the feature "surge control,” adding: "We can treat 700 bu. of seed per hour on a continuous-flow basis.”

Both custom-built KSI conveyors feature cleated belts and slow running speeds, to prevent seed damage. They can handle seed at up to a 45° angle. A rubber-lined seed ladder at the end of each conveyor limits the beans' fall to 1' increments, to minimize damage.

So far, everything we've described is very efficient, but not necessarily unique. What is unique, for a farm-scale setup, are the two custom-built scales—one for each product tank—that combine digital counting heads with 600-lb. platforms.

"The counting scales let us measure the weight of the product tanks and divide the contents into any increments we want,” says Williams. "We tell the scale how many pounds of soybeans we want to treat, and the scale matches the chemical to the flow of soybeans on a weight-by-weight basis.

99% accuracy. "This is much more accurate than calibrating the volume of the treatment to the speed of flow of the seed, using buckets and stop watches, as is usually done when treating at the farm level,” Williams explains. "We usually get 99% accuracy—99.6% to 99.8% is not uncommon.”

There's also a conventional 5,000-lb. platform scale under the output tank. "The three scales let us check calibration with every batch, by matching the units of product applied to the units of seed treated,” says Williams.

From the output tank, seed can be loaded into bulk bags or boxes or conveyed to a truck. Trucks can be pulled inside for loading.

The treater is contained inside a building—ventilated with 24” variable-speed hoghouse fans, to control dust--which also serves as a seed warehouse. "We can treat seed any time of the day or night, and even when it's raining,” says Williams. "If we can't work outdoors, we can go treat seed.”

Other features include agitation built into the chemical inductors, stainless steel catch basins under the tanks and inductors and a 3-phase vibrator welded to the bottom of the output tank to shake loose the last few soybeans.

Planning pays. "I've looked at hundreds of dealer- and retail-level seed treaters, and I've never seen one with a more thought-out design,” says Mike Reed of Bayer Crop Science. "Measuring treatments by weight, rather than volume, is much more accurate, and I have only seen such systems in commercial setups. The two hoppers are round, sloping downward, perfectly sized—much more professional than most. They took a lot of thought and effort.”

Williams built the seed treater, and bought the building that houses it, in partnership with Womack, who operates a seed business and also helps Williams on his farm. Besides treating Williams' own seed, they custom-treat seed for other farmers. 

For Williams, that creates a business advantage on top of the agronomic benefit. "Custom seed treating makes it possible for me to have the assistance of Nic, a college graduate who is knowledgeable enough to run the farm if I have to leave to do something else,” he says. "I couldn't afford to employ him otherwise.” Seed treating also provides a job on the farm for Williams' 16-year-old daughter Caroline, who operates a forklift on weekends and after school.

The treater was constructed by two of Williams' friends, Drew Clements and Justin Parker, who help on the farm in their spare time, just because they enjoy it. Clements, who works as a biomedical equipment technician at a hospital, played a key role in the project because of his knowledge of electronics. Parker, a sales representative for an industrial supply company, sourced all the steel tubing and fasteners.

Often, the group spent their lunch hours devising plans for the treater. "There's no telling how many Pizza Hut napkins it took to design this thing,” Williams jokes.

On his own farm, the treater lets Williams make last-minute seed treatment decisions based on weather conditions. "If I plant early, I may decide to apply fungicide and insecticide,” he says. "But if I can't plant until June, I'll leave the chemicals in the jug.”

The seed treater makes it easy to conduct on-farm trials of various products, Williams notes. Cost of setting up the system, including improvements to the existing building, totaled about $40,000. 


Share your machinery ideas and win $500.
Entries are judged in 12 categories:

  • technology
  • livestock
  • planters
  • sprayers
  • harvesting equipment
  • chemical handling
  • drills/air seeders
  • shops
  • tillage tools
  • hay tools
  • service trucks
  • miscellaneous

Just send a photograph or sketch and a brief description of your idea to Darrell Smith, Farm Journal, P.O. Box 13018, Des Moines, IA 50310-0018 or e-mail Category winners will receive $500 when the idea appears in Farm Journal. Any idea that is published, even if it is not a category winner, will earn you a check for $100.

You can e-mail Darrell Smith at


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