Calendula officinalis, Pot Marigold belongs to the Aster/Daisy family, Asteraceae, and is indigenous to southern Europe. It ranges from the Canary Islands through southern and central Europe and North Africa to Iran. It has even made its home in the southern parts of the United States, and I am obviously grateful.
I started the seed indoors. It proved to grow well inside and produced a very hardy plant. However, according to Strictly Medicinal Seeds, "It can be grown by direct-seeding into a prepared garden bed in the Spring. Germinates best in cool soils and may take up to 2 weeks to germinate. Space 1 to 2 feet apart."
Generally thought of as an annual where I live, Calendula can also be a perennial in zones 9 or 10. The best growing conditions include well-drained soil at pH 6.6 and full sun.
Plant chemistry for Calendula officinalis:
Constituents include saponins, triterpenes, triterpendiol esters, flavonoids, steroids, tannin, quinines, coumarins, carotenoids, amino acids, polysaccharides, essential and volatile oils.
Actions: antibacterial, antifungal, anti-inflammatory, astringent, vulnerary
The parts used are the flowers and the leaves. Look for the deep orange color for the medicinal properties. The yellow ones are not recommended. Let them wilt briefly before discoloration occurs and then into the olive oil for oil infusion, or into Vodka 50% ABV for a tincture.
Strictly Medicinal regarding Calendula officinalis; "Probably the most all-inclusive medicinal herb, the plant is healing and anti-inflammatory."
I intend to use it for the vulnerary actions. I will add the infused oil to beeswax for a healing salve.
With regard to tincturing the flowers, I have various resources which mention its use.
It has been known to help with peptic ulcers, and to stimulate the lymphatic system.
The flowers are edible, but a word of caution do not ingest if you are allergic to daisies, pregnant, or without seeking professional advice regarding interactions to any medications you may be taking.