How to Sow and Grow Nasturtiums

If you’re looking for an easy, colourful flower that rewards you all summer long, learning how to sow and grow nasturtiums is a great place to start. Whether you’re planting nasturtium seeds in a raised bed, window boxes, hanging baskets or containers, these cheerful annuals are one of the simplest flowers to grow. Known botanically as Tropaeolum majus, nasturtiums thrive in poor soil, are incredibly drought tolerant, and require only minimal care to produce masses of vibrant blooms and lush foliage throughout the growing season.

Not only do nasturtium flowers brighten up the garden with shades of red, orange, yellow and cream, but they’re also completely edible. Their peppery flowers and peppery leaves add colour and flavour to salads, while the green nasturtium seed pods can even be pickled to make the famous “poor man’s capers”. As a natural companion plant, nasturtiums also help attract pollinators while acting as one of the best trap crops for aphids, making them an excellent addition to vegetable gardens.

In this guide, we’ll show you how to sow nasturtium seeds, the best growing conditions, when to plant them, how to care for your nasturtium plants, and how to enjoy beautiful flowers from early summer until the first frosts.

Nasturtium Milk Maid

Why Grow Nasturtiums

Here’s why nasturtiums are such a great choice for your garden:

• Easy to Grow: They require little maintenance and tolerate poor soil, making them perfect for beginners.
• Vibrant Blooms: Available in a variety of warm colours like red, orange, and yellow, they brighten up any garden.
• Edible Flowers and Leaves: Both have a slightly peppery flavour, adding zest to salads, sandwiches, or as garnishes.
• Beneficial Companion Plant: Nasturtiums attract pollinators like bees and butterflies, while also acting as a trap crop for aphids, protecting nearby vegetables.

When to Plant

• Outdoors: Nasturtiums thrive in warm weather, so sow the seeds outside after the last frost date in your area, typically in late spring. Soil temperatures should be at least 13°C for successful germination.
• Indoors: If you prefer to start them early, sow seeds indoors 4-6 weeks before the last frost and transplant them once the weather warms up.

Nasturtium Mahogany Jewel

Preparing the Soil

• Soil Type: Nasturtiums actually prefer poorer, well-drained soil. Fertile soil encourages leafy growth but reduces flowering.
• Position: Choose a spot that gets full sun to partial shade. Full sun encourages more flowers, though they will tolerate light shade.

Choosing the Right Variety

There are many different varieties of nasturtiums, making them suitable for almost every type of garden. Trailing varieties are perfect for hanging baskets, window boxes, and allowing to spill over walls or containers, while climbing varieties can quickly cover fences, trellises and obelisks. More compact varieties are ideal for flower beds, borders and smaller pots.

Whichever variety you choose, all nasturtium plants enjoy similar growing conditions and will reward you with vibrant flowers throughout the summer.

Sowing the Seeds

• Direct Sowing: In your garden bed or container, plant the seeds about 2.5 cm deep and 25-30 cm apart.
• Watering: Water the seeds thoroughly after planting and keep the soil moist but not soggy during germination.
• Germination: Nasturtium seeds typically germinate in 7-10 days, depending on temperature and soil conditions.

Indoor Sowing

• Use biodegradable pots or seed trays, filling them with seed-starting mix.
• Plant one or two seeds per pot about 4 cm deep.
• Keep the pots in a warm, sunny spot and water lightly to keep the soil moist.
• Once the seedlings are 8-12 cm tall, and the weather is consistently warm, they can be transplanted into the garden.

Nasturtium Purple Emperor

Care and Maintenance 

Once your nasturtiums are established, they need minimal care. Here’s how to keep them blooming and healthy throughout the season:

Watering

• While nasturtiums are relatively drought-tolerant, regular watering will encourage better blooming. Water them moderately, aiming to keep the soil slightly moist but not waterlogged.
• Be careful not to overwater, as overly wet soil can lead to root rot.

Deadheading

• Regularly remove spent blooms to encourage more flowers. Deadheading also keeps the plants looking tidy.
• If you’re growing nasturtiums for seeds or want them to self-seed, leave a few flowers to develop seed pods.

Pest Control

• Aphids: Nasturtiums are particularly attractive to aphids, which is beneficial if you’re using them as a trap crop for other plants. However, if aphids become too invasive, a strong spray of water can help dislodge them.
• Caterpillars: These insects also enjoy nasturtium leaves but can be easily picked off by hand if they become problematic.

Nasturtium Bloody Mary

Harvesting and Using Nasturtiums

One of the best parts of growing nasturtiums is that you can use the flowers and leaves in the kitchen.

• Flowers: The vibrant blossoms have a peppery flavour and are great for garnishing salads, soups, and even desserts.
• Leaves: The leaves add a fresh, spicy taste to salads and sandwiches.
• Seeds: You can also collect seeds from the plants. Once the flowers fade, the seeds will develop in pods. Let them dry and store them for planting next season.

 Nasturtium Peach Melba

Nasturtium Peach Melba

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Growing nasturtiums is one of the easiest ways to bring colour, wildlife and edible flowers into your garden. Whether you choose to direct sow nasturtium seeds into the ground after the last frost, or get a head start with indoor sowing, these hardy annuals quickly establish themselves in almost any well-draining soil. They thrive in full sun, cope well with poor soil, and continue producing vibrant blooms throughout the growing season with very minimal care.

From attracting bees and butterflies to acting as an effective companion plant, nasturtiums are as practical as they are beautiful. Their flowers, leaves and even nasturtium seed pods are edible, making them one of the most versatile plants you can grow. Save the dried seeds at the end of the season, allow a few plants to self seed, or collect them to sow again next spring.

Whether you’re growing nasturtiums in a raised bed, borders, containers, or window boxes, you’ll enjoy months of colourful flowers right through until the first frosts. Shop our range of premium nasturtium seeds and discover just how easy it is to grow these cheerful garden favourites.

Video – How to Sow and Grow Nasturtiums