Sow at a depth of approx.
0.0 inches (0.0 cm) and aim for a distance of at least
5.85 inches (15.0 cm) between Snapdragon plants. For optimal germination, soil temperature should be a minimum of
13°C / 55°F.
By our calculations, you should look at sowing Tall maximum about 56 days before your last frost date.
Tall maximum is hardy, so ensure you wait until all danger of frost has passed in your area before considering planting outside.