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 Romaine 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 Valmaine about 53 days before your last frost date.
As Valmaine is tender, ensure temperatures are mild enough to plant out - wait until after your last frost date to be on the safe side.