Single Mix Sweet William Seeds

Sweet William is also known as Dianthus. These beautiful and fragrant flowers are long-lasting in a vase, making them a popular choice for cut flowers. They can be grown in full sun or partial shade and are bound to last several seasons in your garden.

Light is required for germination; press seeds lightly into the seed starting mix, but do not cover them. Sweet William establishes best in cool weather. We recommend planting in the fall in Zones 9 and 10 for the happiest spring blooms.

Planting by Zones

Zones 9-10

• As with many flowers in Zones 9 and 10 and other areas with mild winters, you can plant Sweet William in the fall or spring. Fall plantings can be easier to establish as the plants will get to enjoy cooler temperatures and seasonal rainfall. Dianthus is a cool-season flower that grows best in temperatures between 50–55°F and no higher than 65°F.

Zones 2-8

• Start indoors 6–8 weeks before the last frost. Transplant out after the danger of frost is gone.

Planting Sweet William or Dianthus Seeds

• We recommend that you transplant your Sweet William into the garden after beginning them in starter pots. Dianthus seeds are small and should be sown on the soil’s surface as they need light for germination. Sprinkle seeds on top of well-moistened quality seed starting soil and cover only with a light dusting of finely sifted soil. Bottom water or mist gently to water the seeds. Do not water with a heavy spray as this will cover the seeds with displaced soil.

Growing Sweet William or Dianthus

• Sweet William prefers full sun but can be grown in partial shade. Provide well-drained soil.

Growing Sweet William or Dianthus in Containers

• If you are planting in containers, make sure your container is at least 10″ deep. The larger the container, the more blooms you will get. Keep in mind containers will dry out faster because they have more surface area and less soil to hold onto moisture. No more than one plant is recommended per gallon container.

Harvesting Sweet William or Dianthus Flowers

• Sweet William produces colorful blooms that are long-lasting in flower arrangements. Cut at the ground level and harvest after the first 2–3 small flowers of a flower head have opened. The more blooms you harvest, the more blooms the plant will produce.

Southern California Pro-tips

• Mulch heavily to ensure the soil stays cool and well-watered.
• DO NOT overhead water as this promotes disease.

Companion Flowers/Crops

• Sweet William grows well with other cut flowers. We recommend planting a cut flower garden using strawflower, zinnia,sunflowers, and scabiosa. You will have beautiful blooms to use for arrangements all spring, summer, and fall!

Additional Learning Resources

• New to starting crops from seeds? Please watch our Seed Starting Presentationto learn the basics!
• Learn about growing all our crops on our YouTube page!
• Having pest issues? Check out the in-depth information at the UC Integrated Pest Management site.

Fill your garden with pollinator plants to attract beneficial insects like bees, moths, and butterflies. Learn more about growing Pollinator Plants in our Garden Wisdom Blog.