I like to write articles containing handy gardening tips, secrets, and general botanical and horticultural nerdiness.
Nasturtiums (Tropaeolum majus) are cheery flowers that are so easy to grow that they often self-sow and become weedy in gardens. The flowers come in many colors—maroon, red, orange, yellow, and cream—and often have darker patches of a different color. The seeds of nasturtium are extremely easy to collect, save, and successfully grow the following season, even for the beginner gardener.
How to Harvest Nasturtium Seeds
- When nasturtiums self-sow, they simply drop their seeds on the ground. You will find them there, all around the base of the plants. Some are green (fresh), and some are brown (dried). Just collect them all.
- If you are impatient, you can remove the green ones from the plant as long as they are at a good size and fall off easily (see video).
- Small, immature seeds are unlikely to germinate. For nasturtiums, the bigger the seed, the better the germination rate.
- Take them inside and leave them on a paper towel to dry before storing them. As they dry, they'll get smaller and browner. Make sure they are completely dry before storing, or they could develop mold. This could take several weeks. When dry, remove and discard any blighted, small, or really moldy ones.
- Place the seeds in an airtight container and store them in the crisper section of the fridge. They'll remain viable for several years this way and sometimes even up to a decade.
Note: For more on this process, see my video toward the bottom of the article.
When Is the Best Time to Pick Nasturtium Seeds?
Nasturtium seeds can be collected at any time. They fall off the plant naturally when they are ready, and you can collect them whenever you see them on the ground. You can also pick them off the plant if you're impatient.
What Do Nasturtium Seeds Look Like?
Nasturtium seeds usually appear wrinkled and tan to light brown (see image above). They are often about the size of peas or a tad smaller. They are rarely found still attached to the plant, so to find them, you'll need to push back some of the leaves and look around underneath the plant. The seeds will be in various states of drying.
How Are Nasturtiums Beneficial?
Nasturtiums are useful for growing around vegetable patches, as some species of aphid and mite prefer to feed on them, so they are more likely to leave your vegetables alone when nasturtiums are present. Bees also love nasturtium flowers and will be attracted to any garden that contains them.
If growing vegetables, it's important to have a bee-friendly garden, as bees are great pollinators of most garden vegetables. I've found that even the tiny, native, sting-less bees here in Australia are attracted to the flowers of nasturtiums.
Do Nasturtiums Repel Insects?
The strong, pepper-like oils within the leaves of nasturtiums may actually help to repel certain insect pests from your garden, including some species of moths, beetles, flies, and squash bugs.
Video Tutorial for Collecting Nasturtium Seeds
The video above explains how to collect and store nasturtium seeds for maximum seed viability. A transcript is provided below the video for anyone having difficulty understanding my accent.
Hi; Evan here! today we'll be talking about collecting nasturtium seed. There are few plant seeds easier to collect than the humble nasturtium.
The characteristic wrinkled, tan seeds are rarely found still attached to the plant. To find them you'll need to push back some of the leaves and look around underneath the plant. The seeds will be in various states of drying.
If you are impatient you can remove the green ones from the plant as long as they are at a good size and fall off easily. This flower is reaching the end of its life and you can see the three small seeds starting to develop in the center of the flower. Although normally occurring in threes, sometimes one of the three seeds will not be developed leaving only two good viable seeds. Small seeds that haven't matured yet such as the ones here are unlikely to germinate. With nasturtiums, the bigger the seed, the better the germination rate.
All seeds should be brought inside and left on paper towel to completely dry before storing, this could take up to several weeks, any green seeds will turn brown after drying. It is a good idea to remove any really moldy seeds from the rest of the batch. When we look at nasturtium seed we are actually seeing the wrinkled outer shell surrounding the seed. We generally store and sow nasturtium seed while still in this shell as it doesn't hinder germination and avoids extra work shelling every seed.
Once the seed has dried you can then transfer them to a air-tight container—a jar suits the purpose well. Although nasturtium seed are fairly distinctive it is a good habit to label the jar so you don't forget its contents. Store the seed in the crisper section of the fridge for good long term viability, they will remain good for at least several years using this method and even up to a decade.
That's it for now—happy gardening!
To learn how to start and plant those seeds, read "How to Grow Nasturtiums." For more information about the best seed storage techniques, please see another one of my articles, "How to Save and Store Seeds to Make Them Last as Long as Possible."
anneita on August 30, 2017:
very helpful. thanks for your nformation.