Chip a seed with a hard seedcoat with a knife or razor blade until the seed itself is exposed and water can be taken up. Do not cut into the embryo. Alternatively, rub with a file until seedcoat is sufficiently worn away for water to be absorbed into jthe embryo.
Before sowing it is necessary to break the dormancy of seeds with hard seedcoats, and this can be done artificially by the gardener so that germination will occur as soon as conditions are suitable.
Commercially, the dormancy period is reduced by adding concentrated acid to the seedcoat, which then disintegrates. Simpler and safer methods are to be preferred, however. Seeds of a sufficient size to be handled individually can be chipped by cutting a portion of the hard seedcoat away to expose the seed itself. It is not necessary to reduce or cut away all the seedcoat but merely to allow enough to be removed so that water can enter. The seed will then swell and rupture the remainder of the hard seedcoat.
Smaller seeds and seeds with coats that do not lend themselves easily to chipping can have their seedcoats reduced by scarification. This is a fairly simple process in which the seeds are rubbed with an abrasive substance until the seedcoat is eventually worn down to a level at which water will enter. Possibly the easiest way to scarify seeds is to take a jar with a screw lid and line it with sandpaper. Place the seeds in the jar and then shake until the seedcoat is sufficiently abraded to allow water uptake.
Often a seed with a hard seedcoat also needs to be chilled to break dormancy. In this case the seed is subjected to a warm temperature to reduce the seedcoat before being stratified (see page 33). As most seeds are shed in the autumn, this means that such seeds should be stored dry over winter in a warm environment, stratified in early summer and chilled during the following winter before being sown in the spring.
1 Take a jar with a screw-top lid and line it with a sheet of sandpaper.
2 Place a quantity of seeds with hard seedcoats in the jar and screw on the lid.
3 Shake jar until seedcoats are worn down so that water can be taken up.
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