How Long Do Nasturtium Seeds Usually Last?

It’s easy to purchase seeds and forget about them. Then, when you want to use them, you might find that they’ve expired. If you have some old nasturtium seeds in your garden shed or garage, can you plant them? 

Nasturtium seeds usually last for up to a decade, as long as you store them in an airtight container in the fridge. This makes nasturtiums easy to plant from seeds, and since they grow quickly, they’re ideal for gardeners of all experience levels.

In this article, I’ll explore what you should do to encourage your nasturtium seeds to last for up to a decade. I’ll also provide tips on how to collect the seeds directly from your nasturtium plants, so keep reading to learn more.

How to Make Nasturtium Seeds Last Up to a Decade

Storing nasturtium seeds properly is essential to preserve their quality and allow them to sprout successfully.

Here are some tips to follow so that your nasturtium seeds don’t go to waste:

Dry the Seeds Well

After you’ve collected the seeds from the plant, put them on a paper towel so that they can dry. You don’t want any moisture on them that can lead to mold and reduce their lifespan. If some of the seeds are green, wait until they turn brown before putting them in storage. It will usually take nasturtium seeds a few weeks to dry properly.

Keep Your Seeds in a Dry, Cool Location

Avoid storing them in a plastic container as they require air circulation. A glass jar is better for them, and it’s ideal for keeping the seeds in the fridge as this will prevent humidity and warmth from reducing their lifespan. You could also put seeds in paper packets before putting them in a glass container. 

Put a Desiccant in the Glass Jar

A silica-gel desiccant can be put in the glass to absorb moisture, further helping your seeds to remain dry, as the University of New Hampshire reports.

Make Sure They’re at the Right Temperature

Seeds need to be stored at a temperature of between 32 and 41 °F (0-5° C), which is why a fridge is an excellent place for them. To ensure the seeds experience constant cool temperatures, you should keep the seeds in a fridge drawer that won’t get warm whenever you open the fridge door. 

Scarify the Seeds

Since nasturtium seeds have hard coatings on them, this can reduce their rate of germination. Scarify the seeds by scraping one side of them with a knife until you can see the interior seed coat, as the University of Washington’s Botanic Gardens reports. After scarifying the seeds, store them in water overnight. 

Store Seeds in Your Freezer for Long-term Storage

If you know you’re not going to use your seeds in the near future, you should put them in a glass jar that has a rubber gasket and lid, and then put it in the freezer. Avoid keeping the seeds in a plastic bag, as this can expose them to moisture which will degrade them.

How to Test Your Nasturtium Seed Viability

When you want to plant the seeds, make sure you first warm them to room temperature to prevent moisture from condensing on them. This can cause them to become stuck together.

But, how do you know when your nasturtium seeds are bad and should be thrown away instead of planted in the garden?

If you collected seeds from your nasturtium plant a long time ago and aren’t sure if they will grow, there are some methods to test if the seeds are viable and will germinate:

  • The damp paper towel test: Wet a paper towel and squeeze its excess water so that it’s not soggy. Put five nasturtium seeds on the paper towel. Put it into a plastic bag so it doesn’t dry out. If the seeds are still healthy, they should germinate in about six to 10 days. 
  • The water test: Drop five seeds into a glass of water. Leave them in the water for about 15 minutes. If the seeds sink, they’re still healthy and will germinate. If the seeds float, you should throw them away because they won’t sprout. 

Before planting the seeds in the ground, you can also test a few to see if they will grow indoors. This is known as the germination test.

Here’s how to do it:

  1. Place a minimum of 10 seeds in a row on a damp paper towel. 
  2. Fold the towel over the seeds. 
  3. Put the paper towel in a plastic sealable bag. 
  4. Place the bag in an area of the home that gets higher than 70 °F (21 °C) temperatures, such as on a warm windowsill.

How to Collect Nasturtium Seeds to Make Them Last

An easy way to start growing more nasturtium flowers in your garden is to harvest the seeds from the original plant. They look a bit like tiny brains because they’re so wrinkled. The seeds are large and can be green, white, tan, or brown, depending on how mature they are. 

You’ll notice the seeds start out as green and then become wrinkled and brown when mature. The more wrinkled the seeds, the more they’ve matured. 

These seeds grow in groups of three and can be found attached to the plant. A good tip is to search for mature seeds on the ground underneath the leaves. 

Although you can preserve the seeds for future planting of new nasturtium plants, you can also eat the seeds, such as by pickling them and adding them to salads as an alternative to capers! 

How to Grow Nasturtium Plants From Seeds 

When you’re ready to sow your nasturtium seeds, make sure they germinate by following these tips for both outdoor and indoor gardening. 

Growing Outdoor Nasturtiums 

Here’s how to grow nasturtiums outdoors:

Plant the Seeds 1-Inch (2.54 cm) Into the Soil

You can push the seeds into the soil with your finger. Cover the seeds with soil. 

Choose an Area With a Lot of Sun

The seeds need between six and eight hours of sunlight per day. Although the plants can grow in partial-shade conditions, they won’t bloom as much unless they get lots of sunshine.

Make Sure the Soil Temperature Is 55-65 °F (12-18 °C)

A good soil temperature meter to use to ensure this is the Reotemp Soil and Compost Thermometer, available on Amazon. Since it has a 12-inch (30.48cm) stem, it can be used to measure soil temperature in the ground as well as in containers.

Rake Your Soil and De-Weed It

Raking and de-weeding your soil eensures that the soil will be healthy to promote the growth of your nasturtium plants. 

Water the Soil Before Planting Your Seeds

Watering the soil first helps the seeds to settle into the soil and prevents them from being washed away when you water them later. 

Give the Soil Enough Water

Once the nasturtium plants start to grow, water them once a week when the top inch (2.54 cm) of soil is dry. 

Give the Plants Enough Space

Make sure you plant the seeds 10 inches (25.4 cm) apart from each other if you’re planting multiple seeds. 

Thin the Seedlings

When the seedlings can be seen through the soil, which should happen after two weeks, you should thin them so they’re 11.8 inches (30 cm) apart. Thinning is when you remove some of the seeds that were put too close together as it enables the remaining seeds to survive and thrive. 

Growing Indoor Nasturtiums 

While you might want to add beautiful nasturtium flowers to your garden, these plant seeds can also grow successfully indoors.

Here are tips to ensure success:

Add Potting Mix to Their Container

Adding some potting mix will help the nasturtiums to grow, and it’s an excellent alternative to using fertilizer, which can cause the plants to grow many leaves but not many flowers. I recommend Miracle-Gro Moisture Control Potting Mix, available on Amazon. It makes plants grow larger and absorbs more water than regular potting soil, so you won’t risk overwatering your plant. 

Plant the Seeds 1/2-Inch Deep (1.27 cm)

Planting deep enough will ensure they have enough soil covering them so they will sprout.

Water the Seeds Lightly After Sowing Them

The soil should be moist without becoming saturated.  

Grow the Nasturtiums in Enough Sun

Ensure you keep the container in an area of the home that gets a lot of sunlight daily – strive for 6 to 8 hours of sunlight every day. 

Knowing how to prepare the seeds before growing them – whether outside or inside- has a great impact on their ability to germinate. For example, should you soak the nasturtium seeds before planting them or not? Read my blog post to learn: Should You Soak Nasturtium Seeds Before Planting?


If you want to grow nasturtium plants in the garden, you’ll appreciate that their seeds can last for many years. However, you have to ensure that you store the seeds correctly to prevent them from losing the ability to germinate.

This involves: 

  • Drying them thoroughly before putting them in storage to prevent mold
  • Storing them in a glass jar in the fridge to protect them from warmth and humidity
  • Storing them in your freezer for safe long-term storage
  • Preparing them for planting by warming them to room temperature

Alexander Picot

Alexander Picot is the founder of and its lead content writer. He created the website in 2022 as a resource for horticulture lovers and beginners alike, compiling all the gardening tips he discovered over the years. Alex has a passion for caring for plants, turning backyards into feel-good places, and sharing his knowledge with the rest of the world.