A satisfying aspect of growing dianthus is the ease with which they can be propagated. Garden pinks look great when several varieties are grown in adjacent clumps that spread and mingle to form a raised carpet of color. In a few seasons your dianthus will have self-seeded readily, with an interesting blending of color as varieties hybridize among themselves.
The best germination rates are achieved when the seed of border carnations, annuals and pinks is fresh. The seed is held in an upright capsule formed inside the dried calyx. When ripe, it's easy to shake out. Seeds need no special treatment before sowing, though their coating is brittle and they should be handled carefully. If you are gathering your own seeds and want to store them for later use, ensure that they are kept dry and cool in a dark place. Pinks can be sown directly into open ground in late spring, though you will get better results from early indoor sowing. Cultivate the soil so that its texture is finely crumbled and consistent. Sow the seeds thinly, barely cover with a light layer of fine soil and keep it moist until the first sign of green appears above ground. When the seedlings are large enough to handle, thin them and protect from disturbance by birds. For gardeners who want numerous plants, it makes more sense to start them indoors and transplant them into the garden later as small, established plants to fit in with a landscaping plan. Indoor sowing means you are less dependent on favorable weather when the tiny seedlings are vulnerable to wind and cold. They can be sown under warm cover (60-70�F/15-20�C) in winter. Many pinks, planted from seeds, will flower in the same season. Seed is best sown in trays of seed-raising mixture and lightly covered by fine vermiculite or a fine layer of sand. Mist with water and place the tray in a warm position. The soil mix must remain moist to ensure germination, which can be rapid, with the first seedlings appearing within 4-5 days. They should be grown in good light from the outset to ensure compact, sturdy seedlings. If grown in shade, they stretch and are much more prone to damage and damping-off (the failure of the seedling caused by fungi). Well-spaced seedlings, which allow for good air circulation, are also less likely to succumb to damping-off. The first leaves to appear are cotyledons-i.e., seed leaves-that bear no resemblance to the mature grasslike leaves. When the true leaves appear, the seedlings are ready for pricking out or transferring to more spacious living quarters, usually a deeper tray. The seedlings are very delicate at this stage, and they need careful handling. Loosen the soil before attempting to dislodge them and hold them between thumb and forefinger by the seed leaves. Firm them into the soil to avoid air pockets and continue to keep the planting mix moist. When the plants are about 2 in (5 cm) high, they are ready to be transferred to small pots. The young plants are ready for transplanting into permanent positions when the root structure has grown out to the limit of the mix in the pot, probably when they are about 6 in (15 cm) high. If you live in an area with a mild climate, it is best to plant out in the fall, but if you live in an area with a harsh winter, wait until the spring. If raised in a greenhouse, seedlings should be hardened off (acclimatized) by placing their pots in a sheltered, outside position for a few weeks prior to planting. Seeds of annual carnations will germinate in temperatures as low as 40�F (4�C), though it happens more quickly in warmer conditions-two to three weeks at 65�-75�F (18-23�C)-and they will flower approximately 28 weeks from planting. Sow seed in late winter-the earlier you start them off, the earlier they will flower. The seedlings should be potted into shallow trays and planted outdoors in an open sunny situation once all danger of frost has passed. All their side shoots turn into flowering shoots in the season of planting and often they will continue blooming until the first frosts of fall, though it is essential to deadhead them from time to time.