What is Threshing?
Merriam Webster definition:
“to separate seed (from a harvested plant) mechanically.”
These wintry days, as we organize our seeds for sales and growing on, I’m looking for low-budget ways to process the maximum quantity of plant material for seed as possible. I came across a good solution after some research online.
The best resource I found for the design was a blog post by Annapolis Seeds out of Nova Scotia. In the post, they mentioned a design learned from Dan Jason of Salt Spring Seeds. He’s a long-time seed saver and farmer on Salt Spring Island, British Columbia. He has used this design for over 30 years.
Dan was contacted for a few more specific details
The design specifications are pretty straightforward:
A 2 x 3 foot, 3/4 inch thick piece of plywood forms the base of the box (I used 5/8 inch to save money as lumber was so expensive at the time of purchase).
To form the walls, I used 5/4 inch x ~8 inch slabs. These were then screwed on top of the plywood (through the bottom of the box).
Wherever a screw went through solid wood (non-plywood) it was first drilled.
The central, lengthwise 3/4 x 3/4 inch piece was first centred and then I measured the crosswise pieces. The crosswise slats were spaced every 6-8 inches.
One change to the design I made was: one quarter of the box has thinner 1/4 inch slats running crosswise. I am hoping these work better with finer seeds that may otherwise be difficult to process against the thicker slats.
The plant material is ground by foot (with some sort of reasonably protective footwear) and this releases seeds. To avoid damage, the seeds must be well-dried before cleaning with this tool.
Threshing Box in Action
The seeds are dumped out of the box into a container for further screening and chaff removal. Clean seeds will store better than those in a container with a lot of chaff.