Start sweet William indoors 8 to 10 weeks before the last frost or buy plants already in bud. You can also sow them directly in the garden 3 weeks before the last frost for somewhat later bloom; in mild climates, sow in fall for bloom the following spring.1
By our calculations, you should look at sowing Double Dwarf about 49 days before your last frost date.
dianthus
1 Annuals for Every Purpose – Larry Hodgson