The marigolds used in herbal medicine are Calendula officinalis (not to be confused with Tagetes - French Marigolds). Calendula flowers have a wide variety of actions including anti-inflammatory, vulnerary, immune stimulant, anti-fungal and lymphatic.
As an immune tonic and lymphatic it may be used to treat swollen stagnant lymph glands (not active inflammation)
As an anti-inflammatory it may be used by medical herbalists alongside other herbs in the treatment of peptic ulcers (gastric and duodenal) and diverticultis. Externally the anti-inflammatory actions make it useful for nappy rash, eczema, cuts and dermatitis.
It's anti-inflammatory effect is due to the triterpenoid constituents plus the flavonoids
Calendula can be sown straight into the soil, in seed trays or module trays.
When sowing in trays cover the seeds with 1/4 inch of compost.
The cotyledons of Calendula officinalis
The seeds were sown straight into the soil.
As you can see Calendula is a dicotyledon, meaning that it has two seed leaves.