What is scarification? How do a scarify a seed?
Scarification, different from stratification, is the process of penetrating a hard seed coat. Delayed germination caused by seed coats strongly resistant to penetration by moisture can be overcome in various ways. Mechanical rupturing or scarification is practical with many large and medium-sized seeds. Those of sweet peas for example (dark-seed sorts are often slow to germinate, can be chipped with a knife. Canna seeds respond to filing, which is easily done by placing a sharp triangular file on a firm surface and, holding the seed between finger and thumb, stroking it along the upper edge of the file until the seed coat is cut through. Smaller seeds can be scarified mechanically by placing them on a flat surface and rubbing them with emery paper attached to a block of wood.
Hope this is helpful.
Courtesy of the NYBG Plant Information Service