Keep in mind when planting that Silver Queen 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 Silver Queen about 56 days before your last frost date.
As Silver Queen is very hardy, ensure temperatures are mild enough to plant out - wait until after your last frost date to be on the safe side.