Sow
0.12 inches (0.3 cm) deep with a guideline distance of
0.5 inches (1.27 cm). Soil temperature should be kept higher than
10°C / 50°F to ensure good germination.
By our calculations, you should look at sowing Superbo about 20 days before your last frost date.
As Superbo is tender, ensure temperatures are mild enough to plant out - wait until after your last frost date to be on the safe side.