Try to aim for a seed spacing of at least
0.2 inches (0.5 cm) and sow at a depth of around
0.1 inches (0.25 cm).
By our calculations, you should look at sowing Chater's double icicle about 56 days before your last frost date.
Ensure that temperatures are mild and all chance of frost has passed before planting out, as Chater's double icicle is a very hardy plant.