Try to aim for a seed spacing of at least
7.8 inches (20.0 cm) and sow at a depth of around
0.39 inches (1.0 cm). Soil temperature should be kept higher than
10°C / 50°F to ensure good germination.
By our calculations, you should look at sowing D.E.B.R.A. about 42 days before your last frost date.