Try to aim for a seed spacing of at least
1.95 inches (5.0 cm) and sow at a depth of around
0.98 inches (2.5 cm). Soil temperature should be kept higher than
13°C / 55°F to ensure good germination.
By our calculations, you should look at sowing Mixed Red, White & Brown about 28 days before your last frost date.
As Mixed Red, White & Brown is very hardy, ensure temperatures are mild enough to plant out - wait until after your last frost date to be on the safe side.