Sow at a depth of approx.
0.25 inches (0.64 cm) and aim for a distance of at least
11.7 inches (30.0 cm) between Common zinnia plants.
By our calculations, you should look at sowing Pastel Dreams about 21 days before your last frost date.
As Pastel Dreams is tender, ensure temperatures are mild enough to plant out - wait until after your last frost date to be on the safe side.