How to Grow Nasturtium
Tropaeolum majus
Nasturtium (Tropaeolum majus) is a vibrant annual flower prized for its colorful blooms and edible leaves and flowers. Gardeners grow it not just for its ornamental appeal but also to attract beneficial insects while adding culinary interest to salads.
📷 Wikipedia: Tropaeolum majusStarting Nasturtium: indoors or direct sow?
🌾 Sow directly in the garden — Nasturtium is not usually started indoors.
Direct sow seeds outdoors after the last frost date; do not start indoors as Nasturtium prefers warm soil and may struggle if transplanted.
Soil, care & harvest
Prepare well-draining soil with a pH between 6.0 and 8.0, as Nasturtium thrives in these conditions. Since this is a warm-season annual, sow seeds directly outdoors after the last frost date once soil has warmed. Press seeds into the soil at a depth of about half an inch. Expect germination to occur within 7 to 12 days under suitable warmth.
Space plants 10 to 12 inches apart to allow room for their trailing vines to spread. Provide support or trellises if you want the flowers and foliage to climb rather than sprawl across the ground. Water moderately, keeping soil evenly moist but not soggy, and apply light mulch to retain moisture. Fertilize sparingly to prevent excessive leaf growth at the expense of blooms.
Watch for aphids and fungal issues like powdery mildew; encourage air circulation and avoid overhead watering to prevent disease. Harvest leaves, flowers, and seed pods continuously throughout the growing season once plants are established. The edible parts offer a peppery flavor perfect for salads or garnishes whenever they appear.
When to Plant Nasturtium
Planting windows vary by USDA hardiness zone. Look up yours by ZIP code.
| Zone | Start Indoors | Direct Sow | Harvest |
|---|---|---|---|
| Zone 1 | May – June | July – September | — |
| Zone 2 | April – May | June – August | — |
| Zone 3 | April – May | June – August | — |
| Zone 4 | March – April | June – July | — |
| Zone 5 | March – April | May – July | — |
| Zone 6 | March – April | May – July | — |
| Zone 7 | February – March | April – June | — |
| Zone 8 | February – March | April – June | — |
| Zone 9 | January – February | March – May | — |
| Zone 10 | January | February – April | — |
| Zone 11 | January | January – March | — |
| Zone 12 | January | January – March | — |
| Zone 13 | January | January – March | — |
