Sow at a depth of approx.
0.0 inches (0.01 cm) and aim for a distance of at least
11.7 inches (30.0 cm) between Coleus plants. Soil temperature should be kept higher than
65°C / 149°F to ensure good germination.
By our calculations, you should look at sowing Sun about 56 days before your last frost date.
Ensure that temperatures are mild and all chance of frost has passed before planting out, as Sun is a tender plant.