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 Dark Opal about 20 days before your last frost date.
Ensure that temperatures are mild and all chance of frost has passed before planting out, as Purple Dark Opal is a half hardy plant.
When harvesting, cut the whole stem just above a set of leaves to encourage the plant to bush out.
Unless you are saving seeds, cut flowers off the plant as soon as they appear to prolong harvest time.