Direct sow nasturtiums outdoors where they are to grow from March to May. Choose a position in full sun on well drained soil which has been raked to a fine tilth. Sow nasturtium seeds thinly, at a depth of 20mm (¾") in drills spaced 30cm (12") apart and cover seed with its own depth of soil. Water the ground regularly, especially during dry periods. Germination usually takes 7-12 days. When nasturtium seedlings are large enough to handle, thin them to 30cm (12") apart.