Published by Brian Wagner on 11/9/25 in “Growing Flowers from Seed.”
Calendula officinalis, sometimes referred to as Pot Marigold in reference to orange being the color of the Virgin Mary in Catholicism, is a staple garden plant for many people. It has been heavily cultivated and bred – with many unique variations in colour and petals. For most people it is grown as an annual, but for people living in milder climates it is a hardy annual or short-term perennial.
In Zone 9 or warmer it is a short-lived perennial, but it does tend to suffer in the heat – and which makes it perennial only in certain areas of the world such as the Pacific Northwest (where I live). The special bred varieties would typically not behave as perennials, however, even in mild climates.
Calendula is originally native to southern Europe, perhaps around Morocco. Its exact origins are lost to time, however, and older botanical texts note its cultivation since the sixteenth century. It was used to make cheddar cheese orange – and is still used as such by small cheese makers. It has long been used as a dye for clothing and food, as the flowers are edible.
It is certainly a cool season plant, which sends up flowers almost daily in spring and autumn. In the heat of summer it will set seed – but if you deadhead all summer, the plant might survive. It is, of course, native to scrubland ecosystems around Spain and Italy, where it receives full sun all day and thrives in nutrient-poor soil. It does produce better foliage with better soil, but it certainly flowers best in average to poor soil. It is a true sun worshipper, though – it will not flower well in even part shade (although it does persist better in shade, as it’s cooler).
Growing from Seed
Timing is important to get the most out of your calendula schedule. Calendulas can tolerate light frost when planted out, so long as they’re hardened off first. I have planted mine out as early as February without difficulty, but that’s a Zone 9b in Victoria, BC, Canada. If you’re in a Zone 6 consider planting them outside when the snow is gone and night temperatures are just above freezing. Count backwards 2 months, and that’s your sow date.
To grow from seed, it is strongly suggested that you cold stratify the seeds for 2 to 4 weeks. If you harvested your own seeds, I suggest 4 weeks at 4C (40F) of cold stratification. If the seeds were purchased commercially, you can probably skip this step. Seeds are usually inexpensive and easy to find, and even a 50% germination will get you off to a good start. Seeds have a non-deep physiological dormancy that dissipates with either 2-4 weeks of cold stratification or else after-ripening from the passage of time.
Seeds are indifferent to light and will germinate fine in darkness, so they can be buried a bit. Note that Calendula seeds come in different shapes – some look like little boats, others like little spheres. They’re all seeds and they will all germinate (the boat ones not as much as the others, but it won’t matter.)
Pay attention to temperatures. They germinate optimally around 15C (60F). They do not germinate well colder than this. But more importantly, do not use a heat mat. If they get above 25C (80F) the seeds will not germinate well – and above 30C (90F) the seeds die quickly. It’s best to germinate the seeds at 15C (60F) and avoid using a heat mat. Seedlings emerge fast, within 3 to 5 days (especially closer to 20C). They will need potting up around Day 30 and planting outside around Day 60.
References
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Singh R, Tariyal YS, Chauhan JS. Effects of different growth regulators on seed germination and vigor of pot marigold (Calendula officinalis. L). SAARC Journal of Agriculture. 2020 Jul 1;18(2).
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