Coleus is a beautiful plant that can add a pop of color to any garden or indoor space. With its uniquely colored leaves in shades of pink, lime green, and burgundy, it's no wonder it's a popular choice for many gardeners. As a member of the mint family, coleus is easy to grow from seed. Whether you're looking to add some texture to your flower beds or brighten up your indoor space, growing coleus from seed is a great way to get started.
Start seeds indoors six to eight weeks before last frost date. Sprinkle the tiny seeds over soil and lightly cover with seed starting mix. Do not bury as seeds need light to germinate. Place in a warm area in bright but indirect light. Keep moist. Once seedlings appear, it will take three to four weeks before they are ready to be potted or transplanted.
When seedlings have two sets of true leaves and outdoor temperatures are consistently warm, transplant into their own containers or into the garden. Coleus can become dull if left in full sun, so plant in an area that gets shade.
Harvest seeds when petals have dropped from the flowers and remaining seed pods are plump, dry, and brown. Snip the seed pod with scissors or garden shears. Drop the pods into a paper sack. Place the sack in a cool, dry location. Shake the sack every day to keep the seeds from sticking together. Shaking the sack also promotes even drying. Allow seeds to dry for at least two weeks. To check for dryness, press your fingernail into a seed. A dry seed will crack or break. If the seeds aren't dry, check again in two more weeks. Seeds that aren't completely dry are likely to rot. Pour the contents of the sack on a shallow dish or tray and pick out the leaves and other plant debris. Store seeds in a cool, dark place for up to two years.