Sow at a depth of approx.
0.2 inches (0.5 cm) and aim for a distance of at least
1.95 feet (60.0 cm) between Coneflower plants. Soil temperature should be kept higher than
25°C / 77°F to ensure good germination.
By our calculations, you should look at sowing Tomato Soup about 56 days before your last frost date.
Ensure that temperatures are mild and all chance of frost has passed before planting out, as Tomato Soup is a half hardy plant.