Look to ensure a distance
11.7 inches (30.0 cm) between Cinderella's Dress seeds when sowing to make sure your seedlings have enough space.
By our calculations, you should look at sowing Cinderella's Dress about 42 days before your last frost date.
Ensure that temperatures are mild and all chance of frost has passed before planting out, as Cinderella's Dress is a hardy plant.