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Planting and Growing Nasturtiums from Seed

Nasturtium flower with round green leaves

Bright orange nasturtium flowers with distinctive round leaves. Credit: Pixabay

Botanical Name
Tropaeolum majus, T. minus
Grown as
Annual
Toxicity
Non-toxic
Sun Exposure
Full Sun
Partial Sun
Water Needs
Moderate
Height
1–3 feet
Spread
1–3 feet
Soil pH
Neutral
Bloom Time
Summer
Fall
Flower Color
Multicolor
Orange
Red
White
Yellow
Special Features
Container-Friendly
Long Blooming
Low Maintenance
Attracts Butterflies
Attracts Hummingbirds
Attracts Pollinators
Resilience
Drought-Tolerant
Heat-Tolerant
Plant Type
Flowers
Written By: Catherine Boeckmann Executive Digital Editor and Master Gardener

Nasturtiums are among the easiest flowers to grow from seed. Fast-growing and unfussy, they’re as happy spilling from containers as they are scrambling through the vegetable garden. 

Here’s how to plant, grow, and care for nasturtiums.

Planting

When to Plant Nasturtiums

While nasturtium seeds can be sown outdoors anytime after the last spring frost has passed, I usually wait a week or two. The warmer soil helps speed germination, and seeds sprout best when soil temperatures reach 55° to 65°F.

In many areas, you can continue planting nasturtiums throughout the season for a long display of blooms.

You can also start seeds indoors 2 to 4 weeks before your last frost date, but nasturtiums have fragile root systems and don’t transplant well. I usually recommend direct sowing whenever possible.

Where to Plant

Nasturtiums grow well in containers, raised beds, or in-ground gardens, as long as they receive plenty of sun and well-draining soil. Choose a location with well-draining soil and at least 6 hours of direct sunlight daily for the best flowering. 

They’re also commonly planted alongside vegetables, including brassicas, cucumbers, melons, and squashes, where they serve as companion plants. Their bright flowers also attract pollinators, including bees, butterflies, and hummingbirds.

Poor soil is actually preferable. Nasturtiums are light feeders, and rich soil often produces lush foliage at the expense of flowers.

How to Plant Nasturtiums

  • Prepare the planting area by removing weeds and loosening the soil. If desired, mix a small amount of compost into the top few inches of soil. For containers, use a quality potting mix with good drainage.
  • Sow the seeds. Plant seeds 1/2 inch deep and space them 10 to 12 inches apart. Because nasturtium seeds have a hard outer coating, soaking them in water for 8 to 24 hours before planting can speed germination.
  • Water thoroughly after planting and keep the soil lightly moist until seedlings emerge.
Nasturtium seeds held in a hand next to an orange flower.
Nasturtium seeds are large and easy to sow directly into garden soil. Credit: Amverlly
  • Transplant if needed. If you start seeds indoors, harden them off and transplant outside once the risk of frost has past. Just bury the seedlings at the same depth at which they were growing in their nursery pots.
  • Add support. If growing trailing or climbing varieties. Install trellises early, so roots aren’t disturbed later.
Trailing nasturtiums growing over wooden fence.
Trailing nasturtiums climbing over a garden fence.

Growing

Germination

Keep the soil evenly moist but not soggy while seeds germinate. Seedlings typically emerge within 7 to 10 days, although cooler temperatures may slow sprouting. 

Once seedlings appear, reduce watering slightly and allow the soil surface to dry between waterings.

Watering

Although nasturtiums are drought-tolerant once established, they bloom best with regular watering. Container plants dry out more quickly than garden beds and may need more frequent attention.

Water when the top 1 to 2 inches of soil feels dry to the touch, but avoid overwatering. Nasturtiums are sensitive to soggy soil and can rot if their roots stay wet too long.

Fertilizing

Nasturtiums thrive in lean soil and generally don’t need fertilizer. In my experience, mixing a small amount of compost or worm castings into the soil before planting is plenty—after that, I leave them alone.

Pruning and Maintenance

Container-grown nasturtiums may benefit from occasional trimming to keep them compact, but pruning is usually optional. Remove faded flowers (deadhead them) to extend bloom time and encourage the plant to produce more buds.

Seasonal Care

During intense summer heat, nasturtiums may slow or temporarily stop blooming. These are usually signs of heat stress, and plants often rebound when temperatures moderate. Deep watering during hot spells can help reduce stress.

In most regions, nasturtiums are grown as annuals and removed at the end of the season. In frost-free climates, they may persist year-round with light mulching and occasional watering.

Harvesting

When to Harvest

Nasturtium leaves and flowers can be harvested throughout the growing season. Both are edible and have a peppery, watercress-like flavor. For the best flavor, pick young, tender leaves and freshly opened blooms.

Harvest seedpods while they’re still green and immature if you plan to pickle them and use them as a caper substitute.

How to Harvest

Use clean scissors or garden snips to clip leaves, flowers, or seedpods without tearing the stems. Avoid removing more than one-third of the plant at a time so it can continue growing and producing.

Storage and Preservation

To keep your harvest fresh, place cut leaves and flowers in a sealed plastic bag or airtight container in the refrigerator. In my experience, they’ll stay fresh for about 3 to 7 days.

Pests and Problems

While nasturtiums are relatively tough plants that can handle a range of conditions, they’re not completely immune to problems. Most issues are related to light, heat, or pests rather than serious disease.

Common Problems

  • Reduced flowering. If nasturtiums aren’t blooming well, they’re often getting too little sun or too much nitrogen. These plants prefer full light and lean soil. Rich soil produces lots of leaves but fewer flowers.
  • Wilting in heat. During hot weather, nasturtiums may droop, especially if the soil dries out. In my experience, they usually bounce back quickly after deep watering or when temperatures cool slightly.
  • Leggy or weak growth. Low light can cause stretched, spindly stems. Move plants to a sunnier spot if possible.
  • Pest buildup. Because nasturtiums are often used in companion planting near broccoli, cabbages, radishes, and other brassicas, they can attract aphids. I rarely intervene unless infestations become heavy—a strong spray of water is usually enough.

Common Pests

Nasturtiums are often used as trap crops in companion planting, especially near broccoli, cabbages, and other brassicas. Because of this, they commonly attract aphids, and occasionally caterpillars, flea beetles, slugs, snails, or whiteflies.

Nasturtiums growing beside cabbage in vegetable garden.
Nasturtiums are often planted near cabbages and other brassicas as trap crops to attract aphids. Photo by Catherine Boeckmann.

In most home gardens, pest damage is minor and largely cosmetic. Aphids can be rinsed off with a strong spray of water, and larger insects can be hand-picked.

I usually leave my nasturtiums alone. I find pest issues to be relatively insignificant, and I don’t want to deter pollinators from visiting my plants.

Plant Diseases

Nasturtiums may occasionally develop mosaic viruses, leaf spot, or blight, though serious disease is uncommon in home gardens.

To reduce risk:

  • Start with fresh seed from reliable suppliers.
  • Avoid reusing old potting mix.
  • Rotate planting areas each season.
  • Remove plant debris in fall.

Good airflow and well-draining soil go a long way toward preventing problems.

Types

Whether you grow trailing or climbing varieties (Tropaeolum majus) or compact bush types (T. minus), nasturtiums adapt easily to different spaces. I love growing mounding types in pots where their tidy shape shines, while trailing varieties sprawl as cheerful ground covers near melons, cucumbers, pumpkins, and borage. 

Flowers range from soft yellows and peach colors to deep reds and oranges. Leaf color can vary too, with some varieties offering attractive variegation.

  • ‘Alaska Mix’ features variegated foliage and mixed flower colors, making it a standout in containers.
  • ‘Variegatus’ is a trailing type with red or orange blooms, well suited for spilling over edges or climbing supports.
  • ‘Peach Melba’ offers creamy yellow flowers with bright orange-red centers for a softer color palette.
Yellow and peach nasturtium flowers with green foliage.
Nasturtiums come in a range of colors from soft yellow to deep orange and red.

Wit and Wisdom

  • Nasturtium flowers are said to symbolize patriotism and victory in battle. Find more flower meanings here.
  • Nasturtiums have long been grown as edible ornamentals, valued for both their bright blooms and peppery leaves.
  • Each spring, gardeners at Boston’s Isabella Stewart Gardner Museum hang baskets of nasturtiums from the courtyard balconies, training vines to cascade nearly 20 feet for a spectacular 3-week display.

Flowers

About The Author

Catherine Boeckmann

Catherine Boeckmann

Executive Digital Editor and Master Gardener

Catherine Boeckmann loves nature, stargazing, and gardening, so it’s not surprising that she and The Old Farmer’s Almanac found each other. She leads digital content for the Almanac website and is also a certified master gardener in the state of Indiana.

Read more from Catherine Boeckmann

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Comments

<span>Mytai</span> Mon, 03/31/2014 - 17:57
I wondering if Nasturtium plant is going to be poisonous to our dog.
<a title="View user profile." href="/author/editors">The Editors</a> Wed, 04/02/2014 - 10:53

No worries. According to the ASPCA, nasturtium is non-toxic to dogs and cats. 

 <span>Kristin Pass</span> Sat, 03/22/2014 - 07:51
I love the idea of using nasturtium seeds for companion planting. However, everything they would be a companion with is in soil that is enriched with compost and is probably pretty high quality soil. How do you use nasturtiums as companions in this case? I've thought of putting them in pots near the companions but potting soil is also not considered poor. Help?
<a title="View user profile." href="/author/editors">The Editors</a> Mon, 03/24/2014 - 17:31

It's true that nasturtiums don't need a lot of fertility, but we've planted them among our vegetables and they are easy growers so I wouldn't worry much about them! Nasturtiums are great companion plants that can be seeded between cabbages, radishes, tomatoes, cucumbers, zucchini, and beans to deter aphids. Try to find the variety with yellow flowers. Plant after all danger of frost has passed.

 <span>Singer Dorothy…</span> Fri, 02/21/2014 - 12:25
Hi! I just finished my fishpond and waterfall and want to plant something for a "splash of color". Nasturiums sound like a hearty choice. Question, upon reading all the information you have provide, I see the seeds kill parasites in animals...so does that mean they kill parasites in humans? What are ( if any ) the health benefits for us humans, of eating nasturtiums?
<a title="View user profile." href="/author/editors">The Editors</a> Mon, 02/24/2014 - 15:31

Nasturtiums are indeed colorful; they are usually orange, yellow, or red. Their flowers bloom all summer. Both the leaves and the flowers are edible and taste like a mild radish.

Nasturtium has medicinal qualities and known to help fight bacterial infections and certain viruses. However, eating nasturtiums can also have negative side effects. We are not health professionals so you'll want to consult with your health care provider first.  Google "eating nasturtiums health" and you'll see there's a lot of information about this topic.

 <span>Patt Loecher</span> Sat, 02/08/2014 - 17:13
I heard that Nasturtium can work as a natural wormier. Do you know if this could be fed to chicken?
<a title="View user profile." href="/author/editors">The Editors</a> Wed, 02/12/2014 - 17:10

When you plant nasturtium near the coop area the chickens will eat the leaves and flowers, which helps rid them of any internal parasites.

 <span>Kelley Yang</span> Sat, 11/30/2013 - 16:13
Could I plant nasturtiums indoor?
<a title="View user profile." href="/author/editors">The Editors</a> Tue, 12/03/2013 - 11:05

Nasturiums need direct sun to thrive so they are really meant to be an outdoor plant.