Look to ensure a distance
11.7 inches (30.0 cm) between Tylwyth Teg seeds when sowing to make sure your seedlings have enough space.
By our calculations, you should look at sowing Tylwyth Teg about 42 days before your last frost date.
Ensure that temperatures are mild and all chance of frost has passed before planting out, as Tylwyth Teg is a hardy plant.