Try to aim for a seed spacing of at least
5.85 inches (15.0 cm) and sow at a depth of around
0.51 inches (1.3 cm). Soil temperature should be kept higher than
10°C / 50°F to ensure good germination.
By our calculations, you should look at sowing Romanesco natalino about 42 days before your last frost date.
Ensure that temperatures are mild and all chance of frost has passed before planting out, as Romanesco natalino is a tender plant.