Sow
0.23 inches (0.6 cm) deep with a guideline distance of
0.39 inches (1.0 cm). Soil temperature should be kept higher than
16°C / 61°F to ensure good germination.
By our calculations, you should look at sowing Purple Rain about 14 days before your last frost date.
As Purple Rain is very hardy, ensure temperatures are mild enough to plant out - wait until after your last frost date to be on the safe side.