Calendula is an herb that blooms with bright flowers that are commonly used for medicinal purposes. The plant is easy to grow from calendula seeds. It grows best in a garden, but the plant can thrive in large pots as well. When planting calendula seeds, care should be taken to properly prepare the soil, water and fertilize regularly, and to plant in an area that receives adequate sunlight.
Seeds should be planted in late spring or early summer. With proper care, the plants will first produce flowers by mid-summer, usually 40 to 50 days after the seeds are sown. Flowers should continue to bloom until the weather cools enough to produce the first frost of the season. The flowers are usually a bright orange or yellow.
A garden is the most common place to plant calendula seeds. The plants will grow best in fertile soil that is well-drained, but they are very tolerant of low-quality soil. Seeds should be planted 1/4 of an inch (0.6 cm) deep. Calendula plants usually grow to be 12 to 36 inches (31 to 91 cm) tall and seeds should be planted at least 12 inches (31 cm) apart. Germination of the calendula seeds will usually occur within 7 to 14 days after planting.
The area where calendula seeds are planted should receive at least partial sunlight for eight hours each day, but full sun is ideal. As the plants grow, they should be watered regularly when the soil is dry to the touch, usually once or twice per week. Fertilizer can be added to the soil around the calendula plant once a month to give it extra nutrients. Mulch can also be added to the garden to prevent the growth of weeds around the plants.
Dead flowers or leaves should be removed from the plant to encourage new growth. Several days after blooming, the mature flowers can be cut from the plant and used for medicinal purposes. Calendula is a self-seeding plant that will grow well for many years.
Insects are very attracted to the calendula plant, with aphids being a common problem for many gardeners. The plants should be treated with an insect repellent to keep them from being attacked by the insects. Plant diseases may also be a problem. Calendula is prone to mildew if planted in a hot, humid climate or a very rainy one, and should be treated with a fungicide if mildew growth is observed on the plant.