Seeds cleaning

(Dr. Laurent Legendre - February 2003 - )


To prevent seeds from rotting during storage or after sowing, ripe seed capsules must be rapidly dried after harvest. The seeds must also be stored away from contaminating plant debris. The following steps help.


1-     Harvest fully mature seed capsules (they harbour brown stems at their base) before they open. There is only a very short window of time of no more than a couple days between seed capsule maturity and capsule opening, so, watch out!


2-     Place the seed capsules in a paper bag loosely closed and leave them at room temperature for 1 to 3 days depending on how wet the seed capsules were. There could be moisture on the surface of the seed capsules (our plants live, and we grow them, in a humid air) and there is often heavy moisture in the lumen of the seed capsules (empty space between the central placentation where the seed are located and the walls of the capsule). Sometimes, some drops of water can even be seen through the translucent capsule walls. The seed capsules often burst open during this treatment.


3-     Place the seed capsules at the center of a white paper sheet (A4 or B4 format).


4-     With a toothpick, smash the seed capsules to release all of the seeds. For some species, the seeds need to be brushed off with the toothpick from a central ball-like structure.


5-     With the open end of a ball-end ink pen, touch gently the large, non-seed, material. They will stick to the ink of the ball of the pen which helps to discard them.


Tilt the paper sheet while tapping it gently until the seeds start rolling. Collect them in the seed pack (see below for constructions). Pollen grains, seed capsule debris and dead seeds (often skinnier than normal ones), will stick to the paper by static electricity and can thus be separated from the live seeds. If the seeds are still contaminated by plant debris or dirt, repeat the process as many times as necessary. Dead plant material infects easily during storage and would contaminate the seeds of the same seed pack.