Calendula in Zone 6B — Southeast

Calendula is a fantastic addition to any Southeast garden. The cheerful blooms are edible, adding a peppery zest to salads, and they have medicinal properties too. Plus, the bright orange and yellow flowers bring a pop of color to your garden throughout our long summer, attracting pollinators.

Our hot and humid summers can be challenging, but with proper timing, you can enjoy Calendula from spring through fall. The 208-day growing season in Zone 6B gives you plenty of time to get multiple harvests from these beauties.

Starting Calendula indoors is an option, but honestly, it's usually not necessary here in the Southeast unless you're after a very early bloom. If you want to get a jump start, begin indoors in early to late February, about six weeks before you plan to transplant. Use seed trays with a good seed-starting mix, provide warmth (a heat mat helps), and ensure they get plenty of light, either from a grow light or a sunny windowsill. Don't forget to water from the bottom to keep the soil evenly moist without soaking the seedlings. Given our moderate springs, direct sowing often works just as well.

Transplant your Calendula seedlings outdoors in late March through early May, once the threat of frost has passed. Before you move them outside permanently, harden them off by gradually exposing them to outdoor conditions for about a week. Start with an hour or two of shade and increase the time each day. Space them 8-12 inches apart to allow for good air circulation, which is crucial in our humid climate to prevent fungal diseases. Keep an eye on the weather forecast; a late cold snap can still happen in the Southeast during this time.

Direct sowing Calendula is a breeze in the Southeast, and often the preferred method. Sow seeds directly into well-prepared soil from late March through early September. Calendula seeds germinate best in soil temperatures between 65-75°F, which we often hit pretty early here. Just make sure the soil is loose and well-draining. Plant seeds about 1/4 inch deep and space them 8-12 inches apart. Direct sowing is less work, but be mindful of slugs and snails that might snack on the young seedlings.

Calendula needs moderate watering, especially during our hot and humid summers. While they can tolerate some drought, they thrive with consistent moisture, particularly in the spring and fall when temperatures are cooler. During the hottest part of summer, they might even go a little dormant if it gets too dry.

A good rule of thumb is to check the soil moisture about 2 inches deep – the "finger test." If it feels dry, it's time to water. Aim for about 1 inch of water per week, either from rainfall or irrigation. Water at the base of the plants to avoid wetting the foliage, which can encourage fungal diseases in our humid climate.

Signs of underwatering include wilting leaves and stunted growth. Overwatering, on the other hand, can lead to yellowing leaves and root rot. A layer of mulch around the base of the plants helps retain moisture and suppress weeds, but avoid piling it up against the stems, which can trap moisture and cause rot.

Deadheading is key to keeping your Calendula plants blooming throughout the season. Regularly remove spent flowers to encourage the plant to produce more blooms instead of focusing on seed production. Simply snip off the flower heads just below the bloom.

You can deadhead throughout the growing season, from spring until the first frost. If you want Calendula to self-seed, leave a few flowers on the plant to mature and drop their seeds. As the first frost approaches in late October, you can let the remaining flowers go to seed if you want a volunteer crop next year, or pull up the plants to prevent unwanted spreading.

You can expect your first Calendula harvest about 45 days after planting, generally from early May through early November in our Zone 6B Southeast gardens. Harvest the flowers when they are fully open and at their peak color. The petals are most flavorful and potent at this stage.

To harvest, simply snip the flower heads off the plant with scissors or pruning shears. Avoid damaging the surrounding foliage. Regular harvesting encourages continuous blooming, so the more you harvest, the more flowers you'll get.

As the first frost approaches in late October, harvest all the remaining flowers, even the smaller ones. You can dry them for later use or use them fresh. If you let the flowers dry on the plant, you can collect the seeds for next year's planting.

Here are some common problems you might encounter with Calendula in the Southeast:

Powdery Mildew

• What it looks like: White or grayish powdery coating on leaves, stems. Leaves curl, yellow, and die.
• What causes it: Fungi thrive in warm days, cool nights, and moderate humidity, which we often get here. Dry leaf surfaces favor it.
• How to fix/prevent it: Improve air circulation by spacing plants properly and pruning. Remove affected leaves promptly. Neem oil or potassium bicarbonate sprays can help. A milk spray (1 part milk to 9 parts water) is surprisingly effective.

Aphids

• What it looks like: Clusters of tiny soft-bodied insects (green, black, or white) on stems and leaf undersides. Sticky honeydew residue. Curled or distorted new growth.
• What causes it: Rapid-reproducing sap-sucking insects. Populations explode in warm weather, which we have plenty of. Ant colonies may farm them for honeydew.
• How to fix/prevent it: Strong water spray knocks them off. Encourage ladybugs and lacewings (natural predators). Insecticidal soap for heavy infestations. Neem oil works systemically. Avoid excess nitrogen fertilizer.

Whiteflies

• What it looks like: Tiny white, moth-like insects that flutter around the plant when disturbed. Yellowing or silvering of leaves. Sticky honeydew residue.
• What causes it: Sap-sucking insects that thrive in warm, humid conditions. They are attracted to stressed plants.
• How to fix/prevent it: Hang yellow sticky traps to catch adult whiteflies. Strong water spray to dislodge them from plants. Insecticidal soap or neem oil, applied thoroughly to the undersides of leaves. Ensure plants are well-watered and fertilized to reduce stress.

Southeast Specific Challenges: Our hot, humid summers and wet-summer rainfall create the perfect environment for fungal diseases like powdery mildew. The humidity also favors pests like aphids and whiteflies. Good air circulation and regular monitoring are key to keeping your Calendula healthy here.

Calendula makes a great companion plant for many vegetables in the Southeast garden. Planting Calendula near tomatoes and peppers helps to repel pests like tomato hornworms and aphids. Calendula also attracts beneficial insects like ladybugs and lacewings, which prey on harmful pests.

Green beans also benefit from Calendula planted nearby. Calendula helps deter bean beetles and other bean pests. There aren't any specific plants to avoid planting near Calendula, making it a versatile and beneficial addition to any garden bed.