Sow at a depth of approx.
0.47 inches (1.2 cm) and aim for a distance of at least
0.99 inches (2.54 cm) between Radish plants. For optimal germination, soil temperature should be a minimum of
13°C / 55°F.
By our calculations, you should look at sowing Black Spanish Round about 28 days before your last frost date.
Black Spanish Round is half hardy, so ensure you wait until all danger of frost has passed in your area before considering planting outside.