Keep in mind when planting that Swan Blue & White is thought of as very hardy, so this plant will typically do well in a variety of different extremes of cold temperature.
Try to ensure a gap of at least
11.89 inches (30.48 cm) when sowing to prevent overcrowding your seedlings.
By our calculations, you should look at sowing Swan Blue & White about 56 days before your last frost date.
Ensure that temperatures are mild and all chance of frost has passed before planting out, as Swan Blue & White is a very hardy plant.