Keep in mind when planting that Serenity Purple is thought of as half hardy, so it will need protecting in periods of cold weather.
Aim to sow
0.04 inches (0.1 cm) deep and try to ensure a gap of at least
11.7 inches (30.0 cm). Soil temperature should be kept higher than
18°C / 64°F to ensure good germination.
By our calculations, you should look at sowing Serenity Purple about 56 days before your last frost date.
As Serenity Purple is half hardy, ensure temperatures are mild enough to plant out - wait until after your last frost date to be on the safe side.