Sow at a depth of approx.
0.49 inches (1.25 cm) and aim for a distance of at least
5.85 inches (15.0 cm) between Lettuce plants. Soil temperature should be kept higher than
5°C / 41°F to ensure good germination.
By our calculations, you should look at sowing Red fire about 53 days before your last frost date.
Ensure that temperatures are mild and all chance of frost has passed before planting out, as Red fire is a tender plant.