What Is a Dormant Seed?

Winter Hardy

• Dormancy refers to a seed-producing plant's capacity to withstand winter freezes. A seed-producing plant that is winter hardy, or more dormant, is better able to grow in northern climates. A dormant seed remains alive but it is not active metabolically and it cannot germinate. The seed is actually asleep and waiting for the right conditions at which time it will waken.

Reason for Dormancy

• The reason seed dormancy occurs is to make sure that a certain species survives. Dormancy aids the survival of the species by retarding or delaying germination. The process of germination is instead dispersed over time. If the conditions aren't ideal at a particular time, some of the seeds simply wait and germinate later when the conditions are more favorable.

More Rather Than Less Dormant

• A seed that is more, rather than less, dormant is usually easier to grow because there is less spoilage in the summer. On the flip side, a more dormant seed is a harder seed, which produces a lower yield and takes longer to sprout.

Hardseededness

• Another type of dormancy is due to hardseededness, which is caused by the seed coat that surrounds the seed and creates a physical barrier that alters the uptake of water. The seed coat also doesn't allow expansion of the germinating seed. Germination is the result of the respiration of stored food within the seed, and if the seed doesn't get oxygen, which can occur if the seed coat is impermeable to the uptake of oxygen, germination can't occur. When hardseededness is an issue, the seed needs varying temperatures in order to germinate. Hardseededness can make it impossible for shrubs and trees to germinate when the seed unit is a drupe (fruit with a pit inside) or a nut.

After-Ripening

• When plants are domesticated, sometimes the mechanisms that nature put in the plant to ensure dormancy are bred out of them and they will show pre-harvest sprouting, which is called viviparous germination, according to Seedimages.com. When a seed is kept in dry storage this tends to makes it lose control over dormancy and germination. When a plant loses the dormancy mechanism that nature gave it, this is considered after-ripening, or the loss of the dormant state that occurs over a period of time. When the seeds go through after-ripening, the seed must experience a time of quiescence, or calm, in order to separate from the mother plant and become autonomous.