Try to aim for a seed spacing of at least
9.75 inches (25.0 cm) and sow at a depth of around
0.39 inches (1.0 cm). Soil temperature should be kept higher than
18°C / 64°F to ensure good germination.
By our calculations, you should look at sowing Shanghai Green Choy about 14 days before your last frost date.
As Shanghai Green Choy is tender, ensure temperatures are mild enough to plant out - wait until after your last frost date to be on the safe side.