Sow at a depth of approx.
0.51 inches (1.3 cm) and aim for a distance of at least
5.85 inches (15.0 cm) between Broccoli plants. Soil temperature should be kept higher than
10°C / 50°F to ensure good germination.
By our calculations, you should look at sowing Happy Rich about 42 days before your last frost date.
As Happy Rich is tender, ensure temperatures are mild enough to plant out - wait until after your last frost date to be on the safe side.