Post harvest processing, cleaning and sorting
Separating the seeds from plants usually falls into two types of processing techniques:
- Wet – when the seeds are enclosed in fruits, drupes, berries or covered in some sort of damp or gooey material or even inside sticky resin. Often this process involves simply washing the seeds with water. But sometimes this also involves fermentation, rotting processes or imitating being eaten and excreted by animals or birds to remove natural germination inhibitors that surround the seed or seed coating. And some seeds do not germinate at all if left to dry out and must stay damp to successfully grow.
- Dry – when the fruits or flowers release the fully ripe seeds at a time when they are fully dried out and often the whole plant itself or the above ground part dies and dessicates. Sometimes once the seeds are fully ripe they can be removed and left to dry away from the plant material.
Some fruits and the seeds that are inside them will continue to ripen after being removed from the plant once they have reached a certain stage of development. The seeds can be removed from these fruit physically and then either washed or left to dry out. Examples being the cucurbit family (eg. squash and pumpkins) and the solanum family (eg. tomatoes).
Some plants produce very clean seed naturally while some can be very messy or have husks and sharp hard enclosing structures that make it very difficult to clean and sort. Each plant family tends to have an ‘easier’ way to harvest and process their seeds.
Wet
- Fermentaion
- Washing and cleaning
- Water winnowing
- Drying
Dry
- Drying
- Threshing
- Winnowing
- Sieving
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