Understanding Nasturtium Seeds and Their Potential
Nasturtium seeds are the starting point for one of the most versatile and forgiving flowering plants in the British garden. Known scientifically as *Tropaeolum majus*, nasturtiums are prized not only for their cheerful, trumpet-shaped flowers in shades of orange, yellow, red, and pink, but also for their peppery leaves and seed pods, which are edible and add a zesty note to salads and dishes. When you embark on growing nasturtium from seeds, you are choosing a plant that thrives in a wide range of conditions, making it an excellent option for both novice gardeners and experienced horticulturalists seeking low-maintenance colour.
- Nasturtium seeds produce vibrant, edible flowers and leaves.
- They are exceptionally easy to grow from seed.
- Ideal for borders, containers, and even trailing displays.
- Offer a unique peppery flavour to culinary creations.
The appeal of nasturtium seeds extends beyond their visual and gustatory contributions. They are natural companions for many vegetables, acting as a deterrent to certain pests like aphids and whiteflies, making them a valuable addition to an organic garden. Unlike more delicate annuals, nasturtiums are generally robust, tolerating poorer soils and even some drought once established. This resilience means that the primary challenge often lies not in keeping them alive, but in managing their vigorous growth and ensuring they flower prolifically rather than producing excessive foliage.
Choosing the Right Nasturtium Seeds
The market offers a diverse array of nasturtium seeds, catering to various garden aesthetics and purposes. You can select between bushy, compact varieties perfect for containers and bedding, or vining types that are ideal for scrambling over walls, trellises, or spilling from hanging baskets. Colours range from deep reds and vibrant oranges to soft apricots and yellows, with some varieties featuring bi-coloured petals or striking variegated foliage. When purchasing nasturtium seed, look for reputable suppliers to ensure good germination rates and true-to-type flowering. Consider the mature size and habit of the plant when making your selection; for instance, 'Cherry Rose' offers a lovely bushy habit, while 'Alaska' series provides attractive variegated foliage alongside its blooms.
Comparing Nasturtiums to Other Annuals
When considering annuals to sow from seed, nasturtiums often stand out due to their unique combination of hardiness, edible qualities, and pest-deterring properties. While plants like petunias and begonias offer spectacular floral displays, they typically require more specific care regarding soil pH, watering, and feeding. Marigolds are similarly robust and can deter pests, but their flavour profile and growth habit differ significantly. Sweet peas, beloved for their fragrance, are climbers that demand support and can be more susceptible to mildew. Nasturtiums, by contrast, often perform well even in relatively poor soil, making them a more forgiving choice for gardeners seeking colour without intensive management. Their peppery taste also sets them apart from the purely ornamental appeal of most other common annuals.
Cultivating Nasturtium Seeds: From Sowing to Bloom
The journey from a humble nasturtium seed to a flourishing plant is remarkably straightforward, largely because these seeds are large and easy to handle, and germination is typically rapid and reliable. This ease of cultivation is a significant advantage for gardeners, reducing the potential for disappointment often associated with starting plants from seed.
When and How to Sow Nasturtium Seeds
For the best results in the UK, nasturtium seeds can be sown directly into their final growing position outdoors from April onwards, once the risk of frost has passed. Alternatively, for an earlier start, you can sow them indoors in pots about 2-3 weeks before the last expected frost. Use a light, peat-free compost and sow one or two seeds per pot, burying them about 1-2 cm deep. Ensure the compost remains consistently moist but not waterlogged. Nasturtium seeds germinate best in warmth, ideally around 15-20°C. Once the seedlings have developed a few true leaves and all danger of frost has gone, they can be transplanted into their garden beds or containers, spacing them according to the variety’s mature size.
When sowing directly outdoors, prepare the soil by loosening it and removing any weeds. Nasturtiums actually prefer slightly poorer soil; overly rich soil can lead to lush foliage at the expense of flowers, so avoid adding excessive compost or manure at this stage.
Caring for Your Growing Nasturtiums
Once established, nasturtiums are remarkably self-sufficient. Regular watering is beneficial, especially during dry spells and when plants are flowering, but they are quite drought-tolerant once their root systems are developed. Aim to keep the soil consistently moist, but allow the surface to dry out slightly between waterings. Deadheading spent flowers can encourage more blooms, though they often self-seed prolifically. As nasturtiums are susceptible to aphids, regular inspection is wise. A strong jet of water can often dislodge minor infestations, and for more persistent problems, consider using an insecticidal soap or horticultural oil, ensuring it’s safe for edible plants if you intend to consume any parts of the flower.
Troubleshooting Common Nasturtium Seedling Issues
While generally robust, problems can arise. Poor germination might be due to old seeds, sowing too deeply, or insufficient warmth. If seedlings fail to thrive or appear leggy, it often indicates insufficient light or excessive watering. The most common pest is the aphid, which clusters on new growth. Another potential issue is fungal diseases, such as downy mildew, which can affect leaves and stems, particularly in damp, humid conditions. Ensuring good air circulation and avoiding overhead watering late in the day can help prevent such issues. If your nasturtiums are producing lots of leaves but few flowers, it’s likely due to overly fertile soil or insufficient sunlight; try to move them to a sunnier spot and resist the urge to feed them.
Maximising Your Harvest: Edible Nasturtiums and Seed Pods
Beyond their ornamental value, nasturtium seeds unlock a unique culinary dimension, offering peppery flavours that can elevate a range of dishes. Both the leaves and flowers are commonly used in salads, while the unopened flower buds can be pickled, resembling capers. Understanding how to best utilise these edible parts can transform your garden from a source of beauty to a functional ingredient provider.
Using Nasturtium Flowers and Leaves
The vibrant petals and leaves of nasturtiums provide a delightful peppery bite. Flowers are best added just before serving to retain their colour and texture, making them a fantastic garnish for salads, canapés, or even desserts. The leaves, which have a milder but still distinct peppery flavour, can be chopped and mixed into butter, used in pesto, or incorporated into sandwiches and wraps. When harvesting, pick young, tender leaves and flowers for the best flavour and texture. It is crucial to ensure that the plants have been grown without pesticides or chemical treatments, especially if you intend to consume them.
Pickling Nasturtium Seed Pods (Nasturtium Capers)
One of the most intriguing uses of nasturtiums is pickling their unripe seed pods, often referred to as 'nasturtium capers'. These green pods, gathered before they swell and harden, offer a sharp, pungent flavour similar to capers. To make them, collect firm, green seed pods and rinse them thoroughly. Prepare a pickling brine, typically consisting of vinegar (white wine or cider vinegar works well), water, salt, and sugar, often infused with spices like mustard seeds, peppercorns, and bay leaves. Heat the brine and pour it over the pods packed into sterilised jars. Seal the jars and allow them to mature for at least a few weeks before consuming. This process transforms a common garden element into a gourmet condiment.
When to Harvest Nasturtium Seeds
If you wish to save your own nasturtium seeds for future planting or for culinary use (the mature seeds can also be dried and ground as a pepper substitute), allow the flowers to fade and develop into seed heads. These seed heads are small, green, and round initially, gradually turning yellowish-brown as they mature. Harvest them when they are dry and brittle, and easily detach from the plant. Spread them out on a tray in a dry, well-ventilated area to ensure they are completely dry before storing them in an airtight container in a cool, dark place. Ensure you collect seeds from healthy, vigorous plants to maintain desirable traits in subsequent generations. For pickling, however, harvest the pods when they are still firm and green, before they begin to dry out.
Alternative Seeds for Similar Garden Effects
While nasturtiums offer a unique blend of colour, edibility, and ease of growth, gardeners might occasionally seek alternatives that offer similar aesthetic or functional benefits. Whether you are looking for different flower forms, varying levels of hardiness, or specific culinary uses, several other annual seeds can provide comparable garden appeal.
Vibrant Colour and Bushy Habits
For gardeners seeking bright, cheerful colours and a bushy growth habit similar to many nasturtium varieties, consider sowing seeds for marigolds (*Tagetes* spp.) or zinnias (*Zinnia elegans*). Marigolds, in particular, come in a spectrum of yellows, oranges, and reds, and are known for their pest-repelling qualities, much like nasturtiums. Zinnias offer an even wider array of colours and flower shapes, from simple daisies to complex dahlias, and are excellent for cutting. Both are easy to grow from seed directly sown after the last frost.
Edible Flowers and Peppery Notes
If the edible aspect of nasturtiums is a primary draw, other options include calendula (*Calendula officinalis*) and borage (*Borago officinalis*). Calendula flowers, often called pot marigolds (though unrelated to true marigolds), have petals that can be used in salads or as a garnish, offering a mild, slightly peppery flavour and vibrant orange or yellow hues. Borage produces stunning blue, star-shaped flowers that have a delicate cucumber-like taste, perfect for flavouring drinks and garnishing dishes. Both are straightforward to cultivate from seed.
Trailing and Climbing Options
For those who appreciate the trailing or climbing habit of some nasturtium varieties, consider sweet peas (*Lathyrus odoratus*) for their intoxicating fragrance and beautiful blooms, or lobelia (*Lobelia erinus*) for cascading masses of blue, purple, or white flowers in hanging baskets and containers. While sweet peas require support and specific planting times, they offer unparalleled scent. Lobelia provides a different texture and colour palette, often used to trail over the edges of pots or walls, filling gaps with vibrant colour.
Considering Companion Planting
Nasturtiums are often used as companion plants. If you are looking for other plants that can benefit your vegetable patch, consider planting dill or sunflowers. Sunflowers, sown directly from seed, provide dramatic height and attract pollinators. Dill can attract beneficial insects and deter pests. While these may not offer the same visual or edible overlap as nasturtiums, they contribute to a thriving, biodiverse garden ecosystem. The key is to match the plant's needs for sun, soil, and water to your garden conditions, ensuring a successful and beautiful display, whether you choose nasturtium seeds or one of their many alternatives.