Marigold (Calendula)
Calendula, also called pot marigold, is not related to the common yellow and orange marigolds that most people know, but is an herb often grown for medicinal purposes. Mexican tarragon (Tagetes lucida) is related, but is mainly grown for culinary as well as medicinal uses. Mexican marigold (T. lemmonii) is also related, but is an evergreen shrub.
Watering
It is best to water marigolds at the base of the plant and not from overhead. The densely double flowerheads will tend to rot with excess moisture. Allow the soil to dry somewhat between waterings, but do water regularly in high heat or dry weather. Marigolds growing in containers should be watered daily as containers dry out quickly.
Soil
Marigolds aren’t too picky about their soil, but will be their best in moderately fertile, well-drained soil. If planted in clay soil or an area that doesn’t drain well, they may not perform as expected.
Harvesting
Cut selectively into the marigold clumps. If you don't remove too many stems at a time, you'll be able to harvest and continue growing throughout the season. For ease of drying and to keep the garden looking tidy, snip individual stems just above the base of the plant.
Medical Uses
Recipes
Add a pinch or two of calendula petals (not the tough green base of the flower) to tossed salads and stir fries. Use them to garnish potato salads and appetizers. Add them to herb butters and rice dishes. In the summertime, whole flower heads can be frozen in ice cube trays, creating decorative ice cubes fit for the finest herbal libation. You can fancy things up even more by freezing the flowers in colorful herbal tea. For one of my favorite recipes, see my article on Herbal Ice Cubes. Harvest flowers with longer stems intact for adorning iced herbal teas and botanical cocktails, and add a sprig of mint for contrast.
Calendula’s petals are more than a fetching culinary adornment. Like other edible blooms, they are loaded with antioxidant compounds. Its colorful petals are high in carotenoids, such as flavoxanthin and auroxanthin.