Seeds should be started indoors prior to your region’s last expected frost. There’s no need to cover oregano herb seeds with soil. Simply mist them with water and cover the seed tray or container with plastic. Place this in a sunny location such as a window to germinate. Plastic should be removed once the seeds germinate, usually in 10 to 14 days. A heat mat, available at many gardening stores, will speed the germination rate if placed under the container. The sown containers or flats need approximately six hours of sunlight per day.