Sow on a windowsill in a propagator or in a greenhouse, three seeds per 15cm (6") pot, 13mm (½") deep in good quality, finely sieved, moist compost at 18-20°C (65-68°F). Germination 5-20 days. Grow on in a warm, frost-free place. Acclimatise the plants to outside conditions before planting out against a sunny fence, shed etc. Alternatively, sow the seed thinly, direct into finely raked, moist, warm, weed-free soil where the plants are to flower in May.