Dormant seeds are unable to germinate even when the conditions for germination are favorable.
Many types of plants in our temperate forests use seed dormancy as a survival strategy. This is because there are ecological advantages for plants with seed dormancy. These include:
1. Delaying seed germination until the conditions for seedling survival are most favorable. For example, seeds may be shed from the plant in late summer or early fall. The germination conditions are favorable for germination, but because winter conditions will occur soon, it may not be the best conditions for seedling survival. By requiring seeds to receive several months of moist, chilling conditions to satisfy dormancy, these seeds will not be able to germinate until spring when conditions for seedling survival are higher.
2. The creation of a seed bank. A seed bank includes the seeds that are shed from the plant that do not germinate for years due to dormancy. A seed bank ensures that not all seeds germinate in a single year. This is insurance against seedlings being exposed to catastrophic conditions (like drought or cold) that kill the entire next generation of a species. It also allows seedlings to grow during favorable years even if the mother plants failed to flower and make seeds.