Story and Photos By Caitlin Potere
Calendula is grown as a self-seeding annual in USDA grow zones two through eight. In areas with warm winters (above 25⁰F), it blooms year-round. Calendula thrives in full sun with well-drained soil. I recommend sowing Calendula seed directly into the garden early to mid-spring. It’s ideal to plant the seeds as soon as the soil is workable since germination benefits from cool weather, but don’t stress too much about timing. I’ve had success planting seeds year-round. Calendula is a self-seeding annual, which means seeds dropped by the plants in the fall will lay dormant on the ground all winter and then sprout the next spring. However, it’s not an aggressively spreading plant, so don’t worry about it taking over your garden.
When spreading seed, expect a good rate of germination. If you only have a few seeds, you can carefully space them and plant ½” deep. You’ll want to space or thin to 6” apart. If you want a big patch, first prepare the soil, then strew the seeds about on the soil surface and gently tamp. Sprinkle a little extra soil on top if you desire, but it’s not required. Calendula grows easily in regular garden soil and requires no extra watering and no fertilizer. It does equally well in the ground or grown as a container plant.
Harvest whole flowers on a dry, sunny day. I like to gather a mixture of peak blooms and flower buds that are just barely starting to open—a tip I learned from Richo Cech of Strictly Medicinals. The flower heads pop right off and are easy to gather by hand. Peak blooms look fresh and vibrant, with the center of the flower plump and intact. You’ll notice a sticky resin start to build up on your fingers (or your scissors!). That’s good: the more resinous, the more medicinal. Rubbing alcohol will remove the resin from fingers and tools.
For culinary use, the fresh flowers can be stored in an airtight container in the fridge for several days. Pluck the petals and sprinkle over soups and salads. For medicinal use, flowers should be carefully dried on a screen or in a dehydrator. You can use an expandable window screen insert from any hardware store. Spread the flowers in a single layer on the screen and place in an area that is dark, dry, and has good airflow. The screen method usually takes two–three weeks to dry completely. If using a dehydrator, set the temperature between 95⁰F and 105⁰F. Spread the flowers in a single layer on the dehydrator racks. Allow 24 to 48 hours for drying. After 24 hours, check flowers every eight to 12 hours for dryness. Store for one to three years in an airtight container, ideally with a food-grade silica packet.
To make an infused oil for topical use, crumble whole dried flowers into a glass mason jar to around the ¾ full mark. Pour organic olive oil over the herb, covering with about ½” of oil and screw the lid on tightly. Place the jar in a dark, warm location and let sit for about four weeks, giving it a good shake a couple times a week. Alternatively, you can speed things up by using a crockpot. Place a washcloth between the jar and the bottom of the crock. Add water into the crockpot up to the tightly closed lid on the mason jar and turn your crock pot on the “warm” setting. Let sit uncovered, adding more water as needed, for 24 – 72 hours. Carefully strain the flowers out of the mason jar using cheesecloth or a fine mesh strainer. You’ve just made Calendula oil! To make a solid salve, gently heat the Calendula oil in a double-boiler and stir in beeswax beads until they dissolve completely. Pour into containers and allow to cool.
Calendula seeds are easy to collect and save for planting or sharing next year. In the late summer, you’ll notice the flowers begin to die back, close into tight green balls, and then turn into brown seed heads. Each flower can produce a dozen or more squiggly-looking seeds. Collect when the seeds are completely brown and feel crispy-dry. Put them in a paper bag or spread on a screen and place in a cool, dry, dark place. Leave them be for a few weeks to allow them to dry out completely. You can leave them in the brown paper bag all winter long or store them in a dry, temperature-controlled place like you would any seed.
One thing to be mindful of: gardeners have developed many ornamental varieties of Calendula, which are bred for beauty or color variety over medicinal qualities. I recommend ordering Calendula officinalis seeds from Strictly Medicinal Seeds located in Oregon.
If you are pregnant or nursing, or trying to become pregnant, avoid internal use of Calendula. (Topical use is safe.) If you have a known allergy to Asteraceae family plants such as ragweed, daisies, or marigolds, avoid using Calendula. Allergic reactions to Calendula are extremely rare; if you are concerned, I recommend doing a small patch test first by applying a tiny amount to the skin and waiting 24 hours. If redness, itching, or raised skin occurs, discontinue use.
If you would like to learn more about adding herbs to your garden, check out my free online class: Herbs for the Michigan Gardener, which covers 20 different medicinal and culinary herbs suited for the southeast Michigan garden. It’s pre-recorded so you can watch at your own pace. Visit CastleRemedies.com and click on “Classes.”
Caitlin Potere is an herbalist and enthusiastic Project Grow community gardener. She has been studying herbs for over a decade and has completed programs with herbalists Jim McDonald and David Winston. Potere manages Castle Remedies, an holistic pharmacy in Ann Arbor, and is also a coordinator of the annual Great Lakes Herb Faire which takes place in Chelsea, Michigan. You can contact her by email, caitlin@castleremedies.com.
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Yarrow is an indispensable herb that you’ll always find growing in my herb garden. Its versatility is formidable, making it an excellent tool in your herbal medicine kit. If you asked an herbalist what single plant they would bring with them to a deserted island, their answer will most likely be “Yarrow!”