Look to ensure a distance
3.9 inches (10.0 cm) between seeds when sowing - bury at a depth of at least
1.95 inches (5.0 cm) deep. Soil temperature should be kept higher than
16°C / 61°F to ensure good germination.
By our calculations, you should look at sowing swedish brown about 14 days after your last frost date.
Ensure that temperatures are mild and all chance of frost has passed before planting out, as swedish brown is a tender plant.