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Seed Germination Times – 4 Affecting Factors & Examples

Seed Germination Times – 4 Affecting Factors & Examples

Observing the germination of seeds for the first time after planting is a truly enjoyable aspect of having a home garden.

How long that takes depends mainly on the seeds themselves as well as the growing conditions. Not all seeds take the same time to germinate. 

How long does it take seeds to sprout? The average time for seeds to germinate is within 2 weeks. Some seeds might germinate in a couple of days, while other plant species might take a few months to a year to sprout. Moisture, soil temperature, and light conditions can impact the time it takes for seeds to sprout as well.

Seeds with hard shells can be treated with soaking to speed up their germination, while others need some time in the fridge to coax them into sprouting.

Read more to find out the average germination time for many plants and the different factors affecting seed germination.

Seed Germination Time Frame

Garden seeds vary in their germination time from a couple of days to a couple of weeks.

Most often though, the time it takes for seeds to germinate is determined by the moisture, temperature of the soil, and the depth of the seed in the soil.

Before you sow the seeds, make sure to provide the ideal conditions to encourage them to germinate quickly.

How Long Does It Take Vegetable Seeds To Sprout?

Vegetables are known for their short germination time. Most vegetables will sprout between one and two weeks from the time you sow the seeds.

To help seeds sprout quickly, make sure that the seeds are covered with soil (use seed-starting mix rather than potting soil) and that they’re planted at the right depth. 

How Long Does It Take Flower Seeds To Sprout?

Flower seeds take even less time to germinate than vegetables. This is especially true of annuals that live only for one season.

On average, flower seeds take between 4 and 7 days to germinate. Perennials might take longer to sprout, and it’s not uncommon for you to wait between 3 and 4 weeks before the seeds sprout. 

What Does a Seed Need To Germinate?

The common misconception is that all seeds need is some water and they will sprout automagically.

This might work for the hardy weeds that sprout between cracks in the pavement, but vegetables and flowers need a little more than just moisture. 

Moisture

The basic prerequisite to getting any seed started is to give it water. Moisture starts the process that leads to seeds breaking their shells and launching stems upward and roots that dive deep into the soil.

Until you expose the seed to water, it remains dormant.

Temperature

Most seeds need a high temperature to sprout, but the plant species will determine the ideal temperature needed for germination.

Some vegetables, such as spinach, will germinate in temperatures as low as 45℉, while tomatoes can only sprout in temperatures above 90℉.

Soil Depth

Not all seeds need to be buried deep in the soil to germinate. Some seeds need light for sprouting. Lettuce is a good example of seeds that you can’t cover with a thick layer of soil.

Other seeds have a limited amount of energy, and if buried deep in the soil , they won’t be able to break the surface.

Oxygen

Oxygen in the soil goes hand in hand with moisture content. You need to strike a good balance between the amount of water in the soil and the oxygen available for the seeds.

If the soil is wet, this will block the seeds’ access to oxygen and prevent germination.

The stages of seed germination both above ground and under the soil.

Factors That Affect Seed Germination

Even when the above germination requirements are present, that wouldn’t guarantee that the seeds will sprout in the expected time frame, if ever.

Some external and internal factors impact seed germination.

Light

While most plant seeds are not affected by light, some seeds are photoblastic. The presence or absence of light is essential for the germination of these seeds.

Lettuce, grasses, and tobacco are good examples of photoblastic seeds that cannot germinate without light. Tomatoes and onions need total darkness to sprout.

Vitality

The health and condition of the seed determine how fast it will germinate. If the seed has good energy storage, it will germinate faster than a sick or damaged seed.

Special Requirements

Some seeds will only germinate in the presence of other external factors. Orchids need a particular fungus in the soil to germinate.

The same applies to parasite plants that only sprout in the vicinity of their host plants. 

Age

Fresh, young seeds have a faster time frame and better germination rate than old seeds. The longer the seed stays dormant, the less likely it will germinate even in ideal germination conditions.

Does Soaking Seeds Help Germination?

Many seeds have a hard shell or a thick coat to protect them against damage, but this hard shell prevents the seed from germinating quickly.

When you soak such a seed in water, the moisture softens the outer shell and helps the seed sprout faster.

Which Seeds To Soak Before Planting

One dead giveaway that the seed needs soaking before you plant it is if it has a hard coat.

The most common seeds that you should soak in water prior to planting are:

  • Cucumbers
  • Winter squash
  • Pumpkins
  • Beans
  • Lupine
  • Beets
  • Fava
  • Chard
  • Sunflower
  • Peas

Days To Germination Chart

How To Germinate Seeds Quickly

The seeds of plants are as diverse as the plant species themselves. While some seeds are quick to sprout, others take their time and might test your patience.

Depending on the plant species, you can follow any of the following tips to speed up seed germination.

  • Paper Towel: Place a paper towel in a jar, and soak it with water. Sprinkle the seeds on the paper towel and replace the lid of the jar. Keep away from the sun until the seeds germinate.
  • Nick the Seed: Some seeds have a hard protective coat. Nick the coat with a sharp blade to allow moisture to penetrate the seed and help it sprout faster.
  • Stratification: Some seeds need exposure to cold and moist conditions to sprout. Soak the seeds and fill a bag with a starting medium. Drop the seeds in the bag and place in the fridge until they sprout.
  • Soaking: Presoak the seeds before planting them.

Related Questions: 

Do Seeds Go Bad?

Seeds can go bad if exposed to humidity or stored in contaminated areas. Old seeds are less likely to germinate than fresh ones.

Will 20-Year-Old Seeds Grow?

Seed germination success rates dwindle the longer the seeds stay dormant. There’s a very good chance that 20-year-old seeds will not sprout.

Conclusion

Seed germination times vary depending on the moisture, oxygen, depth in the soil, and temperature. Some seeds need a special treatment to sprout faster. 

Always read the seed packet carefully, and follow any directions given for best results.