Aim to sow
0.5 inches (1.27 cm) deep and try to ensure a gap of at least
1.95 inches (5.0 cm). Soil temperature should be kept higher than
13°C / 55°F to ensure good germination.
By our calculations, you should look at sowing He-Shi-Ko about 28 days before your last frost date.
Ensure that temperatures are mild and all chance of frost has passed before planting out, as He-Shi-Ko is a very hardy plant.