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How to grow calendula officinalis flowers including a guide to sowing, growing, harvesting and saving seed. Includes ways to use calendula as a companion plant, and the best cultivars for medicinal use.
This piece is a chapter from the ebook, Calendula: A guide to Growing & Using it in Skin Care which covers the topic in much more depth.
If you only grow one skincare flower, choose Calendula officinalis. Known by many as the Pot Marigold, this cheerful and easy to grow flower has a myriad of uses. The flowers can range in color from a buttery yellow to bright orange and being hardy, new plants can produce flowers from May right through to the first frost. Best of all, the more flowers you pick, the more they produce.
It does incredibly well in most open situations and will grow in practically any garden. It’s a flower that thrives on neglect and will grow better for being left alone. Once they’re in bloom, you can pick the flowers to use in making healing natural skincare.
Calendula officinalis growing guide
• Suitable for all zones
• Fuss-free and easy to grow
• Yellow, orange, and apricot flowers
• Full sun to partial shade
• Most soil types but prefer fertile and well-drained
• Plant height: 45-60cm (18-24”)
• Flowers from late spring to the first frost
Sowing Calendula Seeds
Though Calendula officinalis is originally from the Mediterranean, its hardy nature has allowed it to colonize the temperate world. It grows in most soil types and will even tolerate partial shade. They do best in sunny positions though, especially on well-drained soil. Plant them there and they’ll reward you with hundreds of flowers.
Sow the seahorse-like seeds in either autumn or spring. Sowing them in autumn will give the plants a head-start and you’ll see flowers much earlier. Calendula seeds germinate best at between 15-25C (59-77F). You may not see many seedlings emerge if it’s cooler or warmer than this.
In autumn, sow six to eight weeks before the first frost in a tray or modules filled with one-part perlite (or grit) mixed with three parts multi-purpose compost. Top dress with horticultural grit, water it in, and keep moist undercover in a bright place. The seeds should be sown 1.25cm (1/2”) deep.
You’ll see leaves emerge 6-15 days after sowing. With protection from both the cold and slugs the plants will overwinter well and you can plant them outside after the last frost in spring. If growing in a tray, you’ll probably want to plant them individually in modules before winter.
You can sow calendula seeds in modules in spring too. Use the same instructions above and sow 6-8 weeks before the last frost date if you’re starting them off inside or in a heated greenhouse. If your greenhouse is unheated, sow after the last average frost date.
Planting Calendula in the Garden
Calendula will grow in most soil types but does prefer fertile, well-drained soil. If you want a lot of flowers keep this in mind when you sow or plant them outdoors. They will grow in partial sun but I’d avoid growing them in full shade. Some sources may say that you can but these Mediterranean plants are truly sun-loving. When your little plants are two inches tall, harden them off and plant them outside. They’ll grow to their full potential if you can give them 1-2 feet in all directions.
Calendula Ideas and Recipes
Direct Sowing Calendula Seeds
Direct sowing in spring is very easy. Between March and May, and well after the last frost, lightly scatter seeds in rows 18” apart. Protect the emerging plants from slugs using beer traps or another organic solution and when the young plants reach an inch tall, thin to about 15cm (6”) apart.
Allow the plants to continue growing and when they’ve hit 2-3” in height thin them to 30-60cm (1-2 feet) apart. You can dig up the extra ones for replanting elsewhere or to give away. Put weaker plants on the compost pile.
The above is general planting guidance. I personally tend to grow my calendula in thicker plantings, either in a row with plants just a few inches apart or broadcast over an area. When broadcast or allowed to self-sow, I don’t thin them out. They sort themselves out without interference.
Calendula as a companion plant
Though you may be like me and grow calendula for their own purpose, they can also be dotted around the garden to help other plants to grow. They can attract aphids away from prized vegetables and attract more beneficial plants as well.
In the garden, Calendula is often grown as a companion plant to vegetables that need pollination to produce. The vibrant flowers attract insects that will happily flit over to pollinate zucchinis, pumpkins, and cucumbers while they’re there. Calendula officinalis is a companion plant to many edible plants including:
• Asparagus – it deters the asparagus beetle
• Squash and pumpkins – their flowers attract pollinators
• Cabbages, kale, lettuces, and other leafy greens – they draw aphids away from these vegetables
The downside to calendula is that their dense growth creates a nice damp place for slugs and snails to lurk. That means you should avoid planting them directly next to anything you don’t want to be decimated.
Though Calendula is sometimes called a marigold or ‘Pot Marigold’ it’s not closely related to the common marigold you might be more familiar with. That plant is a Tagetes and has different companion planting suggestions.
Calendula growing tips
If you already have mulch of compost or composted manure on the soil you can sow directly into it. Otherwise, apply a mulch of your choice after the plants are a good inch or two tall. Don’t cover the base of the plant but bring the mulch up to within an inch of it. Mulch will keep the soil underneath moist and stop weeds from growing.
Calendula requires very little in the way of aftercare. My main advice on growing them is to not mess with them too much, other than picking the flowers. It’s over-watering and over-feeding that will cause stunted growth and other issues. Let them alone and they’ll happily grow and bloom all summer long.
If your plants are starting to get tall and spindly, you can trim them back. Use scissors or your fingers to pinch back to a leaf node. Aim to keep your plants under 60 cm (two feet) in height. They tend to stay bushier and healthier that way, need less water, and stand up better in the wind.
Calendula has Very Few Pests
As far as pests are concerned, calendula can suffer from aphids later in the season. If you notice an infestation, spray the aphids off using soapy water. Calendula can also suffer from powdery mildew, a type of fungus, when water-stressed or when planted very closely together.
Growing Calendula in Containers
Calendula is adaptable and will grow well in outdoor pots, containers, and window boxes. Aside from the harvest of flowers, they’ll also add a splash of color throughout most of the year. When growing in containers, make sure that the compost is moist but has good drainage. To make a good mix add 1-part grit or perlite with 1-part vermiculite and 3-parts multipurpose. Perlite adds drainage, Vermiculite aerates but also retains water, and the compost contains nutrients and a place for roots to grow. After planting, press the compost down and top-dress it with horticultural grit. This will help the compost retain water and keep weeds from colonizing the surface.
Calendula Flower Blooming Times
Calendula plants will begin blooming 45-60 days after germination and as long as you keep on top of picking the flowers, they’ll continue flowering.
In fact, they’ll bloom all throughout the summer and autumn if you’re diligent with your dead-heading. In mild climates, some will even continue blooming through the winter.
On the other hand, in warm climates or during a hot summer you may find that your plants stop blooming. They’re hunkering down, bearing through the heat, and will start flowering again when it cools down in autumn.
Calendula flowers aren’t just for show, they’re also a skin-beneficial plant and an edible flower. That means picking the flowers in their prime not only spurs more flowers to bloom but you can use the flowers too. One of my favorite ways to use calendula is in healing skincare and handmade soap. You can also use the petals to color and add flavor to food recipes.
Single and Double Flower Varieties
The flowers themselves will usually be yellow to bright orange and 2-3” in diameter. There are different varieties of Calendula officinalis with some blooming as single flowers and others with double rows of petals. Some varieties, like Fiesta Gitano, produce flowers in both yellow and orange and in semi-double to fully double petals You can also buy calendula seeds as mixes so that you could have single, double, yellow, and orange flowers all in the same row.
Most of the 100 or so calendula officinalis cultivars have been bred for the ornamental market. However, petals from all cultivars are edible and medicinal. It just means that the ones better suited for health and skincare are the more resinous varieties.
• Erfurter Orangefarbige – double with orange petals. This is the best cultivar for use in herbal and skin care applications.
• Resina – single with yellow petals and yellow pistils. Another good cultivar for herbal uses.
• Single Orange – single with orange petals and pistil
• Indian Prince – double and orange-red with a dark pistil
• Pink Surprise – double and yellowy-pink
Is Calendula a Perennial or Annual?
Calendula is technically a short-lived perennial and if it isn’t touched by a hard frost it can survive for a least a couple of years. A few of my plants survive each winter (zone 8), though their lower stems sometimes darken and become leggy.
In zones 7 and lower, you grow calendula as an annual. This means that it will probably die off and need re-sowing from year to year. Fortunately, they are prolific seed producers and will self-seed if you let them. These self-sown seeds overwinter and will grow a new crop of calendula in the same place the next year. You can also save seeds and start the sowing process over again the next spring.
Collecting Calendula Seeds
Calendula seeds are easy to collect and save off the plant. Once you’ve made the initial investment of seeds you shouldn’t need to buy them again. Allow some of the flowers to bloom, drop their petals, and transform into green seed heads. As they mature the seed heads will turn brown and they can be cut from the plant before the seeds are released. Cut the seed heads off on their own or with six inches or more of the stem.
Cutting with a bit of stem can be easier but will also remove part of the plant that could continue flowering. Tie the cut stems with a string and then place the flower heads in a brown paper bag. Tie it on so that it won’t fall off. Hang upside down in a warm and airy place until the stems are dry. Give the bag a good shake after this and most of the seeds will fall off. Tease the rest off if need be.
If you’re just cutting the seed heads, scatter them at the bottom of a brown paper bag and leave them in a warm, dry place. When fully dry, use your fingers to pull the seeds out of the heads. Store dried calendula seeds in bags or jars in a cool, dry place, out of direct sunlight. For best germination, use within six years.
Harvesting and using Calendula Flowers
This piece is an excerpt from the ebook, Calendula A Guide to Growing and Using it in Skin Care. It’s a 49-page guide that shows how to grow, harvest, process, and use calendula in healing natural skincare. It also includes over a dozen beauty and skincare recipes including calendula soap, lip balm, bath fizzies, and skin cream.
Head over here for further information and your instant download.