Scarification is a process in botany that involves weakening, opening, or otherwise altering the coat of a seed to encourage germination). The seeds of many plant species are often impervious to water and gases, thus preventing or delaying germination. Any process designed to make the seed coat more permeable to water and gases is known as scarification). Scarification can be done mechanically, thermally, and chemically). Mechanical scarification is the most common type, where the testa is physically opened to allow moisture and air in. Seed coats may be filed with a metal file, rubbed with sandpaper, nicked with a knife, cracked gently with a hammer, or weakened or opened in any other way). Heat, hot water, and acid are other methods of scarification. Scarification is used to speed up the natural processes that normally make seed coats permeable to water and air, and scarified seeds tend to germinate more often and in less time than unaltered seeds). Scarification finds use not just in industry but also in home gardens, where the seeds of plants that are otherwise difficult to grow from seed may be made viable through scarification.