Sow
0.47 inches (1.2 cm) deep with a guideline distance of
3.12 inches (8.0 cm). Soil temperature should be kept higher than
4°C / 39°F to ensure good germination.
By our calculations, you should look at sowing Spitfire F1 about 45 days before your last frost date.
Ensure that temperatures are mild and all chance of frost has passed before planting out, as Spitfire F1 is a hardy plant.