Sow
0.2 inches (0.5 cm) deep with a guideline distance of
1.95 inches (5.0 cm). Soil temperature should be kept higher than
18°C / 64°F to ensure good germination.
By our calculations, you should look at sowing Karnwal about 38 days before your last frost date.
As Karnwal is tender, ensure temperatures are mild enough to plant out - wait until after your last frost date to be on the safe side.