Natives of Central and South American. Our much-loved Nasturtiums are one of the easiest of all flowers to grow from seed. These fast-growing, hardy annuals have bright, bold, long-spurred flowers. In a range of shades they will bloom from summer right through into autumn and the first frosts. As well as attractive heads their leaves are also a pretty circular shape.
Interestingly, the peppery leaves and beautiful flowers are edible and can be added to summer salads, while immature seeds can be picked and used like capers.
How to Sow and Grow Nasturtiums
For best results and the most flowers, grow them in light, poor soil and never feed them. Rich soil encourages foliage growth at the expense of blooms. They will thrive in full sun and in well-drained soil.
Sow outdoors, where they are to flower, 1.5cm(1/2in) deep, directly into finely prepared soil which has already been watered. Sow two seeds together every 20cm(8in). Seedlings usually appear in 21-28 days. Remove the weaker plant, which can be transplanted elsewhere if desired. Water well until young plants are established.
Sow indoors for earlier flowers, 1.5cm(1/2in) deep, individually in small pots of compost. Keep moist. Gradually accustom plants to outside conditions, avoiding frosts, before planting out 30cm(1ft) apart, when frosts are over.
Tip Improve the germination rate by gently filing the seeds with a nail file or soaking in water for a maximum of 8-12 hours, as the seed coat is very hard.