Tropaeolum majus

Sowing and care guidance

Direct-sow Tropaeolum majus seeds after the last frost into well-drained, moderately poor soil in full sun to light shade. In frost-free climates, sow in the cool season; where seasons are short, start under cover in biodegradable pots and transplant carefully after frost to avoid root disturbance. Space generously so plants can trail or climb, and support if vertical growth is desired. Water regularly but allow the surface to dry between waterings; overfeeding reduces bloom. Deadhead to extend flowering, and pinch tips to encourage branching. In containers, use a free-draining mix and avoid pot-bound stress. Provide shelter from harsh winds for tender young growth.

• Avoid overly rich soil; high fertility favours leaves over flowers.
• Sow 2–3 seeds per station, thin to the strongest, and avoid crowding to allow trailing habit.
• Container-suitable; wide pots or baskets with optional support suit the trailing/climbing habit.
• Pollinator-friendly; open flowers are accessible to bees and other visitors.
• Edible; flowers, young leaves, and immature seed pods are commonly eaten—harvest from untreated plants.
• Ornamental; bold blooms and rounded foliage enhance borders, baskets, and trellises.

How do I grow Tropaeolum majus from seed?

Direct sow Tropaeolum majus seeds where they are to flower, as the plants dislike root disturbance. When soil is workable and has warmed after the last frost, rake a fine, well-drained surface in a spot with full sun to light shade. For faster germination, lightly nick the seed coat or soak seeds for a few hours, then sow 1.5–2 cm deep. Place 2–3 seeds per station and thin to the strongest seedling. Keep moisture even until germination (typically 7–14 days). Where seasons are short, start 2–3 weeks before last frost under cover in biodegradable pots and transplant carefully once frost has passed.

When should I sow nasturtium seeds after the last frost?

Sow after all danger of frost has passed and the soil has warmed enough to be comfortably workable. In areas without frost, sow in the cooler part of the year; avoid the peak of hot weather, which can slow germination and flowering. In regions with brief growing seasons, an early indoor start followed by gentle hardening and careful transplanting can extend bloom. Nasturtiums are tender, so protect young plants from late cold snaps.

What sun and soil do nasturtiums prefer?

Nasturtiums thrive in full sun to light shade, producing the most flowers with at least several hours of direct light daily. They prefer well-drained soil that is not overly rich; excessive fertility, especially high nitrogen, encourages leaves at the expense of blooms. A moderately fertile, free-draining garden bed or container mix is ideal. Water steadily but avoid waterlogging; once established in the ground, they tolerate brief dry spells. Their nectar-rich flowers can help attract pollinators.

Can nasturtiums climb a trellis, and what supports work best?

Many Tropaeolum majus cultivars have a trailing habit and will scramble up supports, reaching 1–3 m when guided. They are not true clinging vines, so provide a light framework they can weave through, such as pea netting, mesh, string lines, twiggy branches, bamboo teepees, obelisks, or balcony railings. Gently tuck or loosely tie stems to the support as they grow and pinch the tips to encourage branching. Position supports where they get good light and some shelter from strong winds.

Are nasturtiums good for containers, and how should I care for them in pots?

Trailing nasturtiums are excellent in pots, hanging baskets, and window boxes, where they can spill attractively over the rim. Choose a container with ample drainage, ideally at least 25–30 cm wide for a single plant, and use a free-draining potting mix. Sow 2–3 seeds per pot and thin to one or two plants. Place in full sun to light shade, water thoroughly then allow the top layer to dry slightly between waterings, and avoid heavy feeding, which reduces flowering. Deadhead and trim as needed, and add a small trellis if you prefer an upright effect.

Are nasturtiums edible flowers?

Yes. Tropaeolum majus is widely grown as an edible ornamental; the flowers, young leaves, and immature green seeds are commonly used in the kitchen. Only consume plants that are correctly identified and grown without pesticides, and always rinse parts before use. Avoid tasting ornamental plants of unknown origin, and if you have sensitivities to plant foods, err on the side of caution. Harvest in the cool part of the day for the best quality.

Guidance is compiled from horticultural sources and supplier information and is intended as general advice. Conditions vary widely with microclimate, soil type, drainage, and local seasonal patterns; interpret timings using climate cues such as after the last frost or when soil is workable. Product pages include variety-specific sowing depths, spacing, and any lot- or batch-specific notes; where present, these are the most precise instructions for that seed.

Growing and sourcing overview

Tropaeolum majus seeds offer reliable, colourful growth for borders, containers, and trailing displays. Sow after last frost when soil is workable and warming; in mild climates autumn sowing may be possible. Seeds are large and germinate readily when planted shallowly in well‑drained soil. Full sun encourages abundant blooms, though in very hot summers light afternoon shade can help maintain flower colour. Moderate moisture suits this annual; overly rich soil can lead to lush foliage with fewer flowers. Compact forms suit edging, while trailing selections benefit from light support. Direct sowing reduces transplant shock, but indoor starts can be set out once the risk of frost has passed and seedlings are sturdy. Deadheading can extend the display, and leaving a few flowers to set seed will provide future sowings. For background on varieties, seed quality considerations, and seasonal planning across different garden conditions, further information is available from SeedsChoice.