Keep in mind when planting that F1 Dark Blue is thought of as half hardy, so protect with a row cover whenever the temperatures drop.
Try to aim for a seed spacing of at least
8.97 inches (23.0 cm) and sow at a depth of around
0.0 inches (0.0 cm). Soil temperature should be kept higher than
18°C / 64°F to ensure good germination.
By our calculations, you should look at sowing F1 Dark Blue about 90 days before your last frost date.
Ensure that temperatures are mild and all chance of frost has passed before planting out, as F1 Dark Blue is a half hardy plant.