Aim to sow
0.06 inches (0.15 cm) deep and try to ensure a gap of at least
11.7 inches (30.0 cm). Soil temperature should be kept higher than
24°C / 75°F to ensure good germination.
By our calculations, you should look at sowing Expo Mixed about 56 days before your last frost date.
As Expo Mixed is tender, ensure temperatures are mild enough to plant out - wait until after your last frost date to be on the safe side.