What Is Seed Dormancy?
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What is seed dormancy? It is the temporary inability of a viable seed to germinate even when conditions are otherwise favorable for germination. A seed can be viable and still not sprout, because something holds germination back until the timing is right. This article explains the definition, why plants use dormancy, the main ways it is released, and what the research does not yet settle. The explanation draws on two open-access reviews from the National Library of Medicine’s PubMed Central archive. One covers secondary dormancy in the model plant Arabidopsis thaliana, and the other covers how dormancy is defined and regulated.
Quick answer
- Seed dormancy is the inability of a viable seed to germinate under conditions that would otherwise allow germination.
- Dormancy times germination to the right seasonal environment, and it spreads germination out over time.
- Dry storage and certain temperature treatments can release dormancy, and the right temperature depends on the species.
- Germination rate and dormancy are different things, and the research warns against mixing them up.
The basic definition
One review defines seed dormancy as the temporary inability of a viable seed to germinate under conditions otherwise favorable for germination. The other review gives the same idea in different words: dormancy is the absence of germination of a viable seed under conditions that are suitable for germination. Both definitions require a viable seed. Dormancy describes a seed that is alive and still does not germinate when it could.
The first review also makes a distinction that matters for gardeners. Dormancy is not simply non-germination or quiescence. A seed that is not sprouting is not automatically dormant, and the definition is about a viable seed held back under suitable conditions.
The second review adds a point about measurement. Dormancy is usually measured on a population of seeds, not on one seed. A batch of seeds that does not fully germinate under favorable conditions can be described as having some level of dormancy.
Why plants use dormancy
Dormancy is a timing system. The first review states that seed dormancy functions to time the moment of germination in the right seasonal environment. Dormancy holds the seed until conditions are more likely to support a seedling.
Dormancy also spreads germination out over time. The first review notes that not all the offspring of one plant germinate at the same time or in the same place. Staggered germination means the seeds from one plant do not all respond to the same conditions at once.
The second review places dormancy among the seed traits that determine the start of a plant’s life cycle. Dormancy, germination rate, and longevity all shape when a plant begins to grow. For wild plants, the review says germination should be postponed until the start of a favorable growth season. For crop plants, it says germination should be immediate, uniform and fast.
Types of dormancy
The first review groups dormancy into several types. These include physical dormancy, morphological dormancy, physiological dormancy, and combinational dormancy, which combines more than one type.
Physical dormancy is the easiest type to picture. The review explains that in certain types of physical dormancy, seeds have a hard, impermeable seed coat that has to be weakened before water can be taken up and germination can begin. In those seeds the coat is the barrier, and the embryo cannot start growing until it is weakened.
How dormancy is released
Dormancy can be lifted by treatment. The first review states that primary dormancy is released during dry seed storage, a process called after-ripening. The second review uses similar language: dormancy can be overcome either by extended storage in dry conditions, which is after-ripening, or by imbibition at specific low or high temperatures, which is called stratification. The second review adds that the exact temperature depends on the plant species.
Stratification is the cold-treatment method most often mentioned in the first review. The review describes it as a process in which imbibed seeds are exposed to low temperatures for a period of time before they are incubated at normal temperatures. The seeds have already taken up water when the cold period is applied.
The first review also notes that treatments such as nitrate, or karrikins, which are present in smoke, can alleviate dormancy. The review says these treatments act on the hormone levels of gibberellins or abscisic acid, or on their signaling pathways.
For practical seed handling, the guides on how to check seed viability and how to store seeds for next year cover those topics separately from the science in this article.
The hormone side of dormancy
Plant hormones are central to dormancy. The first review states that gibberellins promote germination, while abscisic acid, called ABA, represses germination. Dormancy-release treatments act on these hormone levels or on the pathways that carry out their effects.
In primary dormancy, the review says ABA is produced by the endosperm and the embryo when the seed takes up water. The review also says ABA breakdown is reduced and ABA sensitivity is increased compared with seeds that are not dormant.
Primary and secondary dormancy
The first review draws a line between primary and secondary dormancy. Primary dormancy is dormancy in seeds that have just been shed by the parent plant. Those seeds cannot germinate under otherwise favorable conditions. Primary dormancy is the form that dry storage and temperature treatments are known to release.
Secondary dormancy is a different situation. The review explains that non-dormant seeds can temporarily block their germination if they are exposed to unfavorable conditions after taking up water. If those conditions last long enough, they can re-induce dormancy. The seed then does not germinate when favorable conditions return. The review calls this phenomenon secondary dormancy.
The review also states that the mechanisms underlying secondary dormancy remain understudied in Arabidopsis thaliana and are largely unknown. Most of the current knowledge on dormancy comes from studies of primary dormancy release in dry seed.
Dormancy and germination rate
The second review warns against mixing up two ideas that are often confused. Germination rate describes how quickly seeds germinate, while dormancy describes the absence of germination under suitable conditions. The review states that reducing dormancy leads to a widening of the environmental conditions at which a seed can germinate, and often to an increase in the rate of germination. It also says that the two should not be mixed up when seed batches are compared.
How we chose
The sources for this article were selected because they are open-access reviews published through the NIH PubMed Central archive, and because each one defines dormancy directly. The first review uses Arabidopsis thaliana as its example species. The second review focuses on the definition and regulation of dormancy through the DOG1 gene. Both were opened and checked on 2026-10-27. The article does not rely on any retail page and does not recommend any product.
What we could not verify
The reviews do not provide one method that works for every seed. Dormancy release differs by species, and the second review explicitly says the temperature for stratification depends on the plant species. The reviews also do not give timing guidance for particular garden plants. Anyone growing a specific species will need a source that covers that species directly.
What the sources do not say
The sources do not provide a number of days of dry storage or a number of weeks of cold treatment for any particular garden seed. They do not describe home methods for breaking seed coats. They also do not describe how to recover seeds that have entered secondary dormancy. Any statement about those topics would need a separate source, and none is included here.
Frequently asked questions
Is a dormant seed the same as a dead seed?
No. The definitions in the reviews require that the seed be viable. A dormant seed is alive but held back from germinating under conditions that would otherwise allow it.
Why do seeds have dormancy?
The first review states that dormancy times germination to the right seasonal environment and spreads germination out over time, so that not all of one plant’s offspring germinate at once.
What releases seed dormancy?
The second review states that dormancy can be overcome by extended dry storage, which is after-ripening, or by imbibition at specific low or high temperatures, which is stratification. The right temperature depends on the species.
What is the difference between primary and secondary dormancy?
Primary dormancy is found in newly shed seeds. Secondary dormancy can be re-induced when non-dormant seeds face prolonged unfavorable conditions after they have taken up water.
Is germination rate the same as dormancy?
No. The second review states that germination rate and seed dormancy should not be mixed up, because they describe different things.
Sources
- A Perspective on Secondary Seed Dormancy in Arabidopsis thaliana, PubMed Central, https://pmc.ncbi.nlm.nih.gov/articles/PMC7355504/ (opened 2026-10-27)
- Seed dormancy back on track; its definition and regulation by DOG1, PubMed Central, https://pmc.ncbi.nlm.nih.gov/articles/PMC7586819/ (opened 2026-10-27)
