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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>Anonymous</span> Fri, 05/03/2013 - 15:09
my son came home with a seed in a pot a while ago, its just started flowering and i have identified it as a nasturtium, it is currently in the kitchen window and is growing rapidly, its getting rather tall, currently about 2 foot tall, does it need trimming to stop it gaining height or do you just leave them to grow? thanks
<a title="View user profile." href="/author/editors">The Editors</a> Thu, 05/16/2013 - 14:43
When plants of the tall type are about 7 inches tall, place a stake or trellis near them for support. It is not necessary to stake or trellis the dwarf type.
<span>Anonymous</span> Sat, 04/27/2013 - 21:56
Hi, I just bought nasturtium, sweet pea and zinnia seeds. It is the end of April in the Columbus area. Should I sow the seeds into the soil directly right now, or should I start them inside? OR- should I wait and sow them into the garden in a few weeks. Thanks!
<span>Anonymous</span> Tue, 04/09/2013 - 07:17
Will nasturtiums handle full sun in the humid summers of Raleigh?
<a title="View user profile." href="/author/editors">The Editors</a> Tue, 04/09/2013 - 11:28
In your area, nasturtiums do best blooming in spring/early summer. Sow mid-March or earlier in pots. Or, you could also sow in late summer for fall bloom.
<span>Anonymous</span> Sun, 03/31/2013 - 15:59
I have just picked some large green seeds. Can I plant them right away or do they have to dry.It is April first and I live in New Orleans.
<a title="View user profile." href="/author/editors">The Editors</a> Mon, 04/01/2013 - 15:53
You want to grab those seeds when they are still green and let them dry on a baking sheet in a cool dark place for a week. Once they are hard, you can store them for next year.
<span>Anonymous</span> Fri, 03/29/2013 - 09:20
I planted Nasturtiums from seed in hanging pots (about 4-6 inches deep with about 6 - 18" spacing), roughly 4-6 wks ago. I They get full sun from 12ish to 7pm in the Houston heat. I am doing best to provide terrible conditions, which they seem to love. I have 3 doing well with several arms coming off on each. I am anxious for them to bloom...is that more of a summer event even in Houston?
<a title="View user profile." href="/author/editors">The Editors</a> Fri, 03/29/2013 - 12:52
In Houston, nasturtiums do best in the cooler months. You can plant them in the early fall, in which case they might bloom later in the fall before a frost stops them; the plants may even survive through the winter if it is an especially mild one. You can also plant in early spring after the last expected spring frost date. They will bloom until the hot weather starts; peak bloom is usually about May into June. They do not like high heat. When summer hits, move the containers to deep shade, and keep up with the watering. The plants may perk up again in fall to give you another floral display. (Please note: We'd recommend sowing nasturtium seeds about 1/2 inch deep.) Hope this helps!
<span>Anonymous</span> Tue, 03/19/2013 - 00:43
My nastartiums are in a pot and under a shade but gets full sun in the morning but they stop growing about 9inch and stay at the same tall without blooming or any change! What can I do? Thanks