Calendula

Calendula (Calendula officinalis) is one of the few edible flower crops with a genuine secondary market: dried petals are used commercially in skin care products, salves, and cosmetic formulations. Fresh edible flowers run $8-14 per pound at farmers markets and specialty grocers (USDA AMS Specialty Crop Market News, 2023). Dried petals fetch comparable prices in the herbalism and cosmetic ingredient markets. A single $1.99 seed packet planted in early spring will give you continuous blooms from late spring through hard frost if you keep the flowers harvested. That’s 5-6 months of production from one packet.

What it actually is

Calendula is in the Asteraceae family, native to the Mediterranean, and has been cultivated for at least 900 years for culinary, medicinal, and dye purposes. It’s sometimes called “pot marigold,” a name that causes confusion with true marigolds (Tagetes spp.) - they are unrelated plants. True marigolds have a distinctive pungent scent; calendula flowers have a mild, slightly resinous fragrance.

The flowers are the edible and commercially useful portion. The orange and yellow pigments are primarily carotenoids - flavoxanthin and auroxanthin - which give calendula its color and are the compounds valued in cosmetic formulations for their reported anti-inflammatory properties (H.A. Kemper, “Calendula officinalis,” Longwood Herbal Task Force, 1999). The petals taste mildly bitter and slightly peppery when raw, neutral when cooked. They’re used to add color to rice, eggs, soups, salads, and baked goods.

The most productive varieties for petal yield are double-flowered types like ‘Resina’ (high resin content, bred for medicinal use), ‘Alpha’, and ‘Neon’. Standard mixed-color varieties produce well and are visually striking.

The ROI case

A packet of calendula seed costs $1.99 and contains 50-100 seeds - more than enough to plant a full row. Each plant produces 0.5-2 oz of fresh flowers per picking, with pickings available every 5-7 days during peak season. Over a full season, one well-managed plant can produce 0.5-1 lb of fresh flowers, worth $4-14 at retail.

The dried petal value is harder to pin down precisely because it varies significantly by customer - farmers market buyers pay differently than cosmetic ingredient buyers. Dried calendula petals for cosmetic use sell in the range of $15-30/lb wholesale and higher retail (American Herb Products Association market surveys, 2022). If you have a local connection to herbalists, soapmakers, or small cosmetic producers, the market is real.

Self-sowing provides cost recovery over time. Let 5-10 seed heads mature on the plant at end of season; calendula germinates reliably from self-sown seed the following spring.

Growing requirements

Calendula is a cool-season annual - it thrives in spring and fall and struggles in summer heat above 80°F. In zones 4-7, plant seeds outdoors 2-4 weeks before last frost date; calendula tolerates light frost and can be sown in early spring alongside lettuce and spinach. In zones 8-10, it’s grown as a winter annual.

Direct sow seeds 0.25 inch deep, 4-6 inch spacing (thin to 12 inches when plants are 4 inches tall). Calendula transplants easily from cell packs if you prefer to start indoors 4-6 weeks before outdoor planting.

Soil pH of 5.5-7.0. Tolerates poor, low-fertility soils better than most flowers, which is part of its value as a companion planting around vegetables. High fertility produces more foliage but can actually reduce flower density. Moderate, average garden soil produces good flowering.

Full sun (6+ hours). Plants in partial shade bloom less vigorously and are more susceptible to powdery mildew.

What goes wrong

Powdery mildew (Erysiphe cichoracearum) is the most common problem, appearing as white powdery coating on leaves, usually in humid conditions or when plants are crowded. Good air circulation prevents most cases. Milk spray (10% milk, 90% water) applied weekly has demonstrated efficacy in suppressing powdery mildew on related species (Wagner Bettiol, “Milk effectiveness in the control of zucchini powdery mildew,” Scientia Horticulturae, 1999). Remove heavily infected plants.

Aphid colonies on new growth and flower buds are common in spring. Beneficial insects (parasitic wasps, lady beetles) usually colonize calendula planting quickly, since calendula’s open flowers are excellent nectar sources for small beneficials. Allow the natural predator population to build before intervening chemically.

Slugs target young seedlings in cool, wet spring conditions. Diatomaceous earth or slug traps protect early plantings.

Heat stress causes flower quality to decline in midsummer - smaller flowers, reduced petal count, bitter flavor. In hot climates, remove plants in June and replant in August for a strong fall bloom.

Harvest and storage

Harvest flowers when they are fully open - petals fully spread and center visible. Don’t wait until petals start to droop or fall. Pinch or cut the stem just below the flower head. Regular harvesting is essential: any flower allowed to go to seed triggers the plant to slow new flower production. If you want continuous bloom, harvest every 3-5 days.

Dry flowers immediately after harvest by spreading in a single layer on a screen or paper in a warm, well-ventilated space out of direct sun. Petals dry faster than the whole flower head, so if you’re drying for petal use, strip petals first. Whole flower heads take 1-2 weeks to fully dry at room temperature; a dehydrator at 95°F takes 1-3 hours.

Store dried flowers or petals in glass jars away from light. Properly dried and stored, they retain color and potency for 12-18 months.

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Related crops: Tomato, Arugula, Chamomile

Related reading: Companion Planting Basics - how calendula functions as a trap crop and beneficial insect attractor alongside tomatoes