Seed Soaking: Tips For Soaking Seeds Before Planting

Soaking seeds before planting is the best way to germinate certain types of seeds, but not necessarily others. Knowing the basics will help.

Small Garden Shovel Next To A Bowl Of Seeds In Water
soaking green pea seeds
(Image credit: Helin Loik-Tomson)

How & Why You Should Soak Seeds Before Planting

Consider soaking seeds before planting them. Think of that little seed as a Sleeping Beauty of the plant world. Viable seeds are living entities, containing tiny embryos that are ready to sprout and grow. But first they must overcome dormancy, "wake up" and germinate. Every type of seed has specific conditions that must be met to break dormancy and, for some, it helps to soak seeds before planting. 

Reasons for Seed Soaking

Soaking seeds before planting can help jumpstart their germination process. This method of seed priming hydrates the seeds, a process that can allow certain seeds to wake up and grow. 

For some seeds, an overnight soaking in water is sufficient to bring the seed out of dormancy. Sometimes hot water works better. Other seeds will leave dormancy if you do seed soaking in hydrogen peroxide. Still others require a soaking in plant hormones like gibberellic acid or cytokinin (kinetin) solution.

Which Seeds Should You Soak Before Planting?

Should you soak seeds before planting them in your garden? The answer is not black and white. For some seeds, seed soaking works wonders; for others, it doesn’t. 

It’s always a good idea to determine the best way to encourage a particular type of seed to germinate before jumping in to soak them. Some seeds require chilling first; others require specific types of scarification like cutting them or scraping them with sandpaper. Some seeds germinate best in darkness, others in sunlight. 

How to Soak Seeds in Water

If you have determined that a particular type of seed will germinate better after soaking, you will want to know how to soak seeds before planting. Fortunately, it isn’t difficult.

Fill a bowl with hot tap water unless you know from a reliable source that the seeds in question will tolerate boiling water. Put the seeds in the bowl and soak for up to 48 hours. Again, different seeds require different soaking times but 48 is generally the maximum. 

Soaking Seeds in Hydrogen Peroxide

One type of scarification used to assist seeds to germinate is soaking them in hydrogen peroxide. Like other methods of scarification,a hydrogen peroxide soak doesn’t work for all seeds, so it’s best to look up the particular seed first. Otherwise, consider using diluted solutions of hydrogen peroxide instead to prevent injury to the embryos, like a 3 percent solution for example. 

How Long to Soak Seeds Before Planting

Generally, experts advise soaking seeds before planting for between 12 and 36 hours. If you aren’t sure which is best for your seeds, you might soak some for 12 hours, others for 24, and still others for 36, and see which works better.

Teo Spengler

Teo Spengler has been gardening for 30 years. She is a docent at the San Francisco Botanical Garden. Her passion is trees, 250 of which she has planted on her land in France.