Try to aim for a seed spacing of at least
2.92 feet (90.0 cm) and sow at a depth of around
0.99 inches (2.54 cm). Soil temperature should be kept higher than
15°C / 59°F to ensure good germination.
By our calculations, you should look at sowing Tricolour about 42 days before your last frost date.
As Tricolour is tender, ensure temperatures are mild enough to plant out - wait until after your last frost date to be on the safe side.
By our calculations, you should look at planting out Tricolour about 14 days after your last frost date.