Keep in mind when planting that Green Spire is thought of as very hardy, so this plant will survive though longer winters with little or no damage.
Try to ensure a gap of at least
4.68 inches (12.0 cm) when sowing to prevent overcrowding your seedlings.
By our calculations, you should look at sowing Green Spire about 63 days before your last frost date.
Ensure that temperatures are mild and all chance of frost has passed before planting out, as Green Spire is a very hardy plant.