Aim to sow
0.39 inches (1.0 cm) deep and try to ensure a gap of at least
5.85 inches (15.0 cm). Soil temperature should be kept higher than
13°C / 55°F to ensure good germination.
By our calculations, you should look at sowing Trailing Rosy Red about 35 days before your last frost date.
Ensure that temperatures are mild and all chance of frost has passed before planting out, as Trailing Rosy Red is a very hardy plant.