Plant seeds shallow as it is easier to germinate that way.
Ensure a distance of 0.5 inches (1.27 cm) between seeds when sowing - look to sow at a depth of approximately 0.12 inches (0.3 cm). Soil temperature should be kept higher than 10°C / 50°F to ensure good germination.By our calculations, you should look at sowing Purple Petra about 20 days before your last frost date.
Basil must be harvested by cutting stems at inter-node points, rather than plucking leaves if it is to remain bushy and full. Purple basil requires lots of warmth – even more than green basils.1
Basil