This potato harvester sorts the rocks from the spuds

A new harvester eliminates one of the more mundane tasks of the potato harvest — separating the rocks from the spuds.

Harvester can tell the difference between a rock and a spud

Alex Docherty says this new harvester is 'priceless,' because of the way it sorts rocks from the potatoes. (Pat Martel/CBC)

Up until this fall, Alex Docherty, chairman of the PEI Potato Board and a potato farmer in Elmwood, P.E.I., would do what most potato farmers on the Island still do today — hire rock pickers. 

This year, he purchased a Spudnik AirSep Harvester, a piece of equipment instead that eliminates one of the more mundane tasks of the potato harvest — separating the rocks from the spuds.

"It's an incredible piece of equipment," he said.

Old way of picking rocks disappearing

Typically, rock pickers stand on top of the moving harvester as it scoops up spuds from the red earth and speeds them along a conveyor belt to a truck driving alongside.

A tradional 'rock picker' grabs stones on the conveyor belt harvester and drops them into a box. (Submitted by Valerie Docherty)

"We would normally have three to four people on the harvester, and they'd only probably be getting fifty per cent of the stones," said Docherty.

Follow the bouncing spuds

But his new harvester has technology that can tell the difference between a rock and a spud.

"It literally takes the stones out of the potatoes itself without anybody touching them," said Docherty.

This potato harvester sorts rocks from the spuds 0:53

As the potatoes and rocks come out of the ground onto the conveyor belt, they pass over a pressurized wind tunnel. Since potatoes are a lot lighter than rocks, they start floating and bouncing, while the rocks drop down onto the conveyor belt and into big boxes.  

And the rock pickers aren't completely out of a job — Docherty said because the new harvester doesn't get every rock, his employees are still needed back at the warehouse to do a final scan of the potatoes — something they are now able to do indoors and out of the cold.

The Spudnik AirSep Harvester can gather and separate a tonne of rocks in just a few minutes. (Pat Martel/CBC)

'It is priceless'

Docherty wouldn't say exactly how much his new harvester cost, except that it was in the hundreds of thousands of dollars. 

A local dealer said they range from $250,000 to $350,000 depending on which features the model includes.

"It is priceless and nine times out of ten, you get exactly what you pay for," said Docherty.

The new harvester is only used about three weeks during the harvest, before it's parked in the warehouse until next year. 

Docherty believes there are currently three harvesters like this being used in P.E.I., a number he believes will increase over time.