Look to ensure a distance
0.39 inches (1.0 cm) between seeds when sowing - bury at a depth of at least
0.23 inches (0.6 cm) deep. Soil temperature should be kept higher than
16°C / 61°F to ensure good germination.
By our calculations, you should look at sowing 3 Colour Purple about 14 days before your last frost date.
Ensure that temperatures are mild and all chance of frost has passed before planting out, as 3 Colour Purple is a very hardy plant.