Scarification of Hard Seeds
While the seeds of many annuals (for example: Hemp, Klip Dagga, Marihuanilla, Wild Opium Lettuce) will germinate easily when sown straight into the soil in spring, many other plants (for example: Acacia, Mimosa, Morning Glory) have hard seed coats that need to be broken before they will grow.
To break the hard outer seed coat a number of methods may be used. The following are some of the more common methods:
- Boiling - Place the seeds in a cup and fill cup with boiling water. Leave seeds to soak as water cools for approx 24hrs. Remove any seeds that have softened and swollen up with water. These are ready to sow. Repeat this process (up to 10 times) on any seeds that are still hard.
- Nicking - If the seeds are large enough, a small knife, file or sand-paper may be used to gently cut or file a small nick or cut in the side of the seed. Be careful not to damage top and bottom of the seed
*Special thanks to Roger Culos for the great pic.