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How to Grow Nasturtium, an Edible Flower

Caren White is a Master Gardener and instructor at Home Gardeners School. She has been associated with Rutgers Gardens for over a decade.

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Flowers have a place in my vegetable garden, not just for their beauty, but also because they attract pollinators. You will always find nasturtiums in my veggie garden both for their beauty and their usefulness. It doesn’t hurt that they are also edible.

What are Nasturtiums?

Nasturtiums (Tropaeolum spp.) are flowering plants that are native to Central and South America. The species most often seen in gardens are T. majus which is a trailing plant and T. minus, which is a dwarf species. Less frequently seen is T. peregrinum also known as Canary Creeper which is a vine.

Nasturtiums are hardy in zones 9 – 11 so most of us grow them as annuals. Depending on the species, they range in size from 1 – 10 feet tall and 1 – 3 feet wide. The leaves, which are edible, are round and bright green.

The flowers are shaped like trumpets. They also have a “spur” on the backs like larkspur. Butterflies and hummingbirds find them irresistible. The colors range from cream, yellow, orange, red and pink. I think I have grown every single color. The flowers are also edible.

The leaves and flowers are eaten raw, usually in salads. They have a crisp, peppery taste.

The flowers have spurs on the back similar to larkspur.

The flowers have spurs on the back similar to larkspur.

My favorite nasturtium, which you will find in my garden every year, is the Alaska Series. It is a dwarf nasturtium with flowers that are red, orange and yellow. The reason that I love it so much is that the leaves are variegated, adding a pop of color before the plants even start blooming. It grows 10 - 12 inches high and 8 – 10 inches wide. I usually plant them as a border.

As if I haven’t already given you enough reasons to add these flowers to your garden, here’s yet another reason to plant them in your vegetable garden. Nasturtiums are a trap crop.

A trap crop are plants that attract certain pests. In this instance, nasturtiums are attractive to aphids, flea beetles, cucumber beetles and squash vine borers. I plant my nasturtiums a few feet away from my cucurbits which are preyed on by cucumber beetles. The idea is that the cucumber beetles will eat my nasturtiums instead of my cucumbers.

So, a quick recap on why you should plant nasturtiums in your vegetable garden: they attract pollinators, predatory insects and they are edible.

My favorite Alaska series with variegated foliage.

My favorite Alaska series with variegated foliage.

How to Grow Nasturtiums

Nasturtiums are best grown from seed. They don’t like having their roots disturbed so they don’t like being transplanted. Although you can buy nasturtium plants from your local nursery, I don’t recommend it. It’s easier, not to mention cheaper, to grow them from seed at home. I provide directions on how to do this below.

Nasturtiums grow best in full sun, but will tolerate a little shade. Plant them in well-drained soil. They don’t need nutrient rich soil, preferring poor soil. There is no need to fertilize them. Fertilizing them will produce more foliage than flowers.

Give them an inch of water each week. Watering is especially important during periods of drought. Nasturtiums struggle in dry conditions.

The seeds are large with hard coats.

The seeds are large with hard coats.

How to Grow Nasturtiums From Seed

Did I mention that nasturtiums are great for children’s gardens? They have large seeds which are easy for tiny fingers to plant. You can start them outdoors in your garden or indoors for a head start.

Nasturtium seeds have a hard outer covering that can make germination difficult. Most experts advise you scarify the seed coat before planting.

Scarifying is a way to make it easier for water to penetrate the seed and encourage the embryo inside to grow. You can either use a sharp knife to nick the seed coat or use fine grain sandpaper to sand down a spot on the outer shell. In either case, you have to be careful not to go too deeply and damage the embryo inside.

I’m a bit clumsy, so I just soak my seeds overnight. That softens up the seed coat enough to encourage germination. You can also plant your seeds without scarification or soaking. They will just take longer to germinate.

Starting Your Seeds Outdoors

The easiest way to plant nasturtium seeds is directly in your garden in the spring after the soil has warmed. In my zone 6 NJ garden, that is the end of May/beginning of June. Plant your seeds ½ to 1 inch deep and 3 inches apart. I’m a lazy gardener so I usually just make a shallow trench ½ to 1 inch deep, drop my seeds in and then cover the whole thing up again. It’s easier than making individual holes and has the advantage that you can see the spacing of your seeds as well as making a straight line if you are planting them as a border as I do.

Keep your seeds well- watered. Germination should occur in 7 – 10 days. Thin the seedlings to 8 – 10 inches apart. You can expect flowers about 30 days after germination.

Starting Your Seeds Indoors

If you want flowers sooner, you can start your seeds indoors 4 – 6 weeks before your last frost. Use peat pots or other biodegradable pot so that you can plant the whole thing in your garden without disturbing the roots.

Plant your seeds ½ - 1 inch deep. I find it easiest when planting large seeds to fill my pots with soil, water them to settle the soil and then use my finger to poke holes in each pot at the appropriate depth. Then I can just drop the seeds in the holes and cover them up.

Keep your seeds well-watered. Germination should occur in 7 – 10 days. You can plant your seedlings outdoors after your last frost when the soil has warmed. Plant them, pot and all, 8 – 10 inches apart. You can expect flowers about 30 days after germination.

© 2021 Caren White

Comments

Caren White (author) on January 22, 2021:

Thank you. My goal is to make gardening accessible to everyone. It's so much easier than you think.

Abby Slutsky from America on January 21, 2021:

I always learn so much from your articles says the reviewer with the black thumb. (Brown would be generous.) These flowers are particularly appealing because I love garnishing food with edible flowers.

Caren White (author) on January 21, 2021:

They are so easy to grow.

Caren White (author) on January 21, 2021:

If you add nasturtiums to your garden, you won't regret it.

Caren White (author) on January 21, 2021:

I love nasturtium flowers in salads. They add color as well as flavot.

Linda Crampton from British Columbia, Canada on January 20, 2021:

Thank you for sharing this information. My father grew nasturtiums and introduced me to their taste. Now that I’ve read your article, I’m very tempted to grow them myself.

Pamela Oglesby from Sunny Florida on January 20, 2021:

I have never growns nasturtiums, so I found this article to be very interesting. Thank you for so much excellent information, Caren.

Peggy Woods from Houston, Texas on January 20, 2021:

My mother-in-law used to grow nasturtiums, and we had some tasty salads using some of the blossoms.