Mix Sweet William Seeds

Surface sow Sweet William seeds just below the soil line — no deeper than ¼ inch. If you want to have your Dianthus Barbatus plants as early as possible, sow seeds indoors 6 to 8 weeks prior to your last frost. The soil temperature should be above 60 °F, and your seeds should sprout in 14 to 20 days. For direct sowing wait until the last frost date, firm your seeds into the ground, and keep your soil moist. The plants should have enough room to breathe if they are 12 inches apart, because crowded plants flop and invite disease.

Full sun is a requirement for strong flowering. At a minimum, six hours of sun is required, but more is always better. These plants can tolerate partial shade, but they stretch towards the sun, and flowering drops. Well-draining soil is more important than rich soil. This is a drought-tolerant flower once it is established, so you can skip the weekly watering routine. Instead, water plant deeply but infrequently. That encourages deep root development, which is exactly what makes these plants resilient to dry spells.

Deadhead the plant regularly, and you extend the flowering period through the summer. Without deadheading, the plants put their energy into producing seed. This is the most important maintenance task for Sweet William flower seeds. After two or three years, the clumps should be split and replanted. The plants self-sow if you allow some of the flowers to go to seed. They are not greedy plants and require very little fertilizer.