Growing the Low-Maintenance, Healthful Calendula

Calendula grows best outside, but if you want to protect your seedlings from the dangers of frost, you can start the growing process indoors. After germinating in seed trays for three to six weeks, transfer the calendula to an outdoor garden plot. Although this hardy plant can survive in any ordinary garden soil, the best results come from light, well-draining soil — ideally neutral to slightly acidic. If the soil is too wet or too dense, the calendula roots may rot.

Most varieties of calendula grow one to two feet tall, though some reach three feet. Each plant's spread is also typically one to two feet, so make sure you plan your calendula plot accordingly. If you'd like a particularly dense patch, place two or three plants close together and they'll grow outwards from each other. As for flowerbed depth, aim for around one foot of soil, but don't worry if you can't quite meet the requirements. The roots of the calendula plant are fairly adaptable, adjusting well to the space they're given.

The sunlight access calendula needs depends on the climate in which it's growing. If you live in an area with moderate temperatures, set your calendula up for full sunlight. These light-loving plants typically do best when they get plenty of sunshine to grow under. If you live in a particularly warm climate, however, you'll find your calendula plants grow better with some light shade. The high heat of intense summers can stress them, leading to drooping flowers.

While your calendula is still in the early growth phase, it's important to water frequently to encourage summer blooms. Well-draining soil comes in handy here, ensuring the roots get plenty of water without rotting. Once the plants are well established (around four to six weeks after germinating), scale back to watering only when the soil is dry. During hot weather, around one inch of water per week should suffice.

Just as calendulas are attractive to homeowners, they're also attractive to several insect species. In fact, many experienced gardeners use these "pest magnets" as trap crops to draw harmful insects away from vegetables and other decorative flowers. Aphids are one of the most common pests you'll find on your calendulas; curled leaves are a common sign of aphid infection. These insects produce honeydew, which in turn attracts ants. You may also find whiteflies on the underside of your calendulas, eating away at the leaves. Thankfully, a strong blast of hose water or a spritz of insecticide is often enough to get rid of all these pests.

Calendula smut is one of the most common diseases your plants may face, and it causes brown spots across the leaves. Both calendula smut and alternaria leaf spot, another fungal disease, can be addressed with a fungicide. Calendulas are also susceptible to powdery mildew, but this fungus is easily prevented by making sure your plants are well-aerated and kept dry from the base upwards. If your plants appear abnormally yellow, they may have been infected with the fatal aster yellows. Sadly, the only way to save your patch from this disease is to remove and destroy any infected plants.

One reason why calendula is such a popular plant is that it doesn't require any special care. These hardy flowers are low-maintenance and adapt well to most conditions, as long as those conditions are not too extreme. If you still want to go the extra mile to ensure your plants bloom big and beautiful, plant them in fertile soil laden with nutritional organic material.

Typically, calendula is only propagated through seeding. Since these plants have a more hollow stem than many others, it can be hard to grow more through cuttings. Thankfully, calendula is naturally self-propagating, with each plant producing and dropping several seeds once it blooms. If you don't want your patch to become too dense, trim the seed heads as soon as the calendula's bloom is gone, or harvest the seeds for future planting.

While calendula can be purely decorative, many people grow the plant to use in oils, salves, and teas. To do so, you'll need to harvest the flowers first. The best time to harvest calendula is when the blossoms are half open, as their medicinal value starts to decline shortly after. Once the morning dew has dried, simply cut or pluck the flower blooms from their stalks. Trimming back the remaining stems afterward can help prevent rot, ensuring your plants will produce more flowers in the coming weeks.

Once you've harvested your calendula flowers, you'll want to dry them. They can be dried outside in moderate sunlight, but an electric dehydrator will get the job done quicker. The dried blooms can then be steeped in water to make tea or broth. Alternatively, infuse them in a neutral oil for use in health and beauty products like salves and poultices. You can also store dried flowers in airtight containers for future use.