Six Ways to Screen and Winnow Seeds
Low-Tech Tools for Threshing Seeds
Here are six devices for separating seeds from debris and chaff:
• Pillowcase or Cloth Sack – Perhaps the most common method of hand threshing, place seed pods in the sack and thrash (“thresh”) it against a hard surface to break the seeds from their coverings.
• Boards – Place harvested seed pods between two boards and apply gentle pressure to crack open the pods. Take care not to press so hard you split the seeds.
• Screens or Strainers – Screens with meshes of varying sizes provide a quick way to separate debris from seeds. Even using a single screen is a vast improvement over hand picking. Screens work especially well for seeds (such as lettuce) that do not have pods. A set of graduated screens will cut out about 80 percent of the hand work. You can build screens yourself or buy them pre-built.
• Wind Power – Outside on a breezy day, drop seed from one container into another and let the wind blow away the unwanted chaff.
• Electric Fan – While wind can be fickle and blow your chaff in unexpected directions, a fan set on low will produce a steady stream of air for winnowing.
• Gravity – This works well for round seeds. Use gravity to help roll seeds down a newspaper into a container. The heavier seeds roll down, while the chaff remains behind.
How to Screen and Winnow Seeds
Using newspaper, wind power and simple screens, this slideshow demonstrates several easy ways to separate seeds from their pods and husks. Many of the methods use materials already found at home.
More about threshing and seed saving:
Threshing Dried Beans: A Low-Tech Method for Small-Scale Growers
How to Save Tomato Seeds
The Seeds of Sustainability