Seed Dormancy

Seed dormancy refers to a natural resting state in seeds in which, despite being viable, they do not germinate straight away. This mechanism prevents a seedling from growing at an unfavourable moment, for example during a dry spell, before the onset of winter, or under other unsuitable environmental conditions.

Seed dormancy is an important protective mechanism in many plant species. It ensures that germination only takes place once factors such as moisture, temperature, light and soil conditions are favourable for further growth.

Causes of seed dormancy can include a hard seed coat, germination-inhibiting substances within the seed, or an embryo that has not yet fully developed. Plant hormones also play an important role in controlling this state.

A distinction is made between primary and secondary dormancy. Primary dormancy is already present when the seed reaches maturity and is part of the plant's natural development. Secondary dormancy can develop later, when a seed that is already capable of germinating is exposed to unfavourable environmental conditions.

Many wild plants show a pronounced degree of seed dormancy, whereas in cultivated plants it has often been reduced through breeding, to allow even and predictable germination. In some species, dormancy can be broken by special pre-treatments such as stratification (a period of cold) or scarification (nicking the seed coat).

For gardeners, seed dormancy is particularly relevant when seed fails to come up as expected, or comes up only slowly or unevenly, despite good germination capacity. Understanding this natural germination inhibition helps in planning sowings more successfully and applying the right pre-treatments.