Calendula in Zone 6B — Mid-Atlantic

Calendula is a fantastic addition to any Mid-Atlantic garden. The bright, cheerful flowers bring a pop of color to your beds, and the petals are edible, adding a slightly peppery zing to salads and other dishes. Plus, it's a great source of satisfaction knowing you can grow your own medicinal herbs right here in your backyard, even with our humid summers.

While the Mid-Atlantic can throw some curveballs our way with variable spring weather and the occasional late frost, Calendula is quite forgiving. Our relatively long 198-day growing season gives you plenty of time to get a few harvests in.

Starting Calendula indoors in the Mid-Atlantic can give you a jump start on the season, but it's honestly not always necessary. If you're eager for early blooms or want to ensure a good harvest before the summer heat hits, then it's a good plan.

Start your seeds indoors in early to late February, about six weeks before you plan to transplant them outdoors. Use seed trays with a good seed-starting mix, keep them warm, and provide plenty of light, either from a sunny window or a grow light. Bottom watering is a great way to keep the soil consistently moist without overwatering.

Given our moderate spring, you may find direct sowing to be just as effective, so don't feel pressured to start indoors unless you have specific goals.

Transplanting Calendula seedlings outdoors in the Mid-Atlantic is best done in late March through early May. Before you move them permanently, harden them off by gradually exposing them to outdoor conditions for about a week.

Plant them 8-12 inches apart in a sunny spot with well-draining soil. Keep an eye on the weather forecast; we sometimes get a late frost in April, so be ready to cover your seedlings if needed.

Direct sowing Calendula is a super easy and effective method in the Mid-Atlantic. You can direct sow from late March through late August.

Prepare the soil by loosening it and removing any weeds. Sow the seeds about ½ inch deep and 8-12 inches apart. Calendula seeds germinate best when the soil temperature is around 70°F, so waiting until the soil has warmed up a bit in late spring or early summer is ideal.

The benefit of direct sowing is less fuss, but the downside is you'll have to wait a bit longer for the plants to mature.

Calendula needs moderate watering in the Mid-Atlantic. While it can tolerate some drought, it prefers consistently moist soil, especially during its peak blooming period. Remember, our summers can be humid, which affects how often you need to water.

In the spring and fall, when temperatures are cooler and rainfall is more frequent, you might only need to water once or twice a week, giving about 1 inch of water each time. During the hotter, more humid summer months, check the soil moisture more frequently. Stick your finger about 2 inches deep into the soil; if it feels dry, it's time to water. Aim for about 1-1.5 inches of water per week during this time.

Water at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases in our humid climate. Signs of underwatering include wilting leaves and stunted growth. Overwatering can lead to yellowing leaves and root rot. A layer of mulch around the base of the plants helps retain moisture and suppress weeds.

Pruning Calendula is all about deadheading to encourage continuous blooming. Throughout the growing season, from mid-May through late October, regularly remove spent flowers by snipping them off just below the flower head.

This prevents the plant from putting energy into seed production and encourages it to produce more flowers. Toward the end of the season, around the time of our first frost in late October, you can let some of the flowers mature and dry on the plant if you want to collect seeds for next year.

You can expect your first Calendula harvest in the Mid-Atlantic from mid-May through early November, about 45 days after planting. The best time to harvest the flowers is when they are fully open, ideally in the morning after the dew has dried.

Gently pluck the entire flower head from the plant, being careful not to damage the surrounding foliage. Regular harvesting encourages the plant to produce more blooms throughout the season. As the first frost approaches in late October, harvest any remaining flowers that look ready to go, as they likely won't survive the cold.

Here are some common problems you might encounter with Calendula in the Mid-Atlantic:

Powdery Mildew

• What it looks like: A white or grayish powdery coating on leaves, stems, and sometimes flower buds. Leaves may curl, yellow, and eventually die.
• What causes it: Various fungi that thrive in warm days, cool nights, and moderate humidity, which are all too common in our Mid-Atlantic summers. Dry leaf surfaces actually favor powdery mildew, which is unusual for fungal diseases.
• How to fix/prevent it: Improve air circulation by spacing plants adequately and pruning if needed. Remove and dispose of affected leaves promptly. Neem oil or potassium bicarbonate sprays can help control the spread. A milk spray (1 part milk to 9 parts water) is also surprisingly effective. Consider planting resistant varieties.

Aphids

• What it looks like: Clusters of tiny, soft-bodied insects (green, black, or white) on stems and the undersides of leaves. You might also notice a sticky honeydew residue and curled or distorted new growth.
• What causes it: These sap-sucking insects reproduce rapidly, especially in warm weather. Ant colonies may "farm" them for honeydew, protecting them from predators.
• How to fix/prevent it: A strong spray of water can knock aphids off plants. Encourage beneficial insects like ladybugs and lacewings, which are natural predators. Insecticidal soap can be used for heavy infestations. Neem oil is also effective. Avoid over-fertilizing with nitrogen, as this attracts aphids.

Whiteflies

• What it looks like: Tiny, white, moth-like insects that fly up in a cloud when disturbed. Yellowing leaves, stunted growth, and sticky honeydew.
• What causes it: Warm, humid conditions allow whiteflies to multiply quickly. They suck plant sap, weakening the plant.
• How to fix/prevent it: Hang yellow sticky traps to catch adult whiteflies. Spray plants with insecticidal soap or neem oil, paying close attention to the undersides of leaves. Encourage natural predators like lacewings and ladybugs. Ensure good air circulation around plants.

Mid-Atlantic Specific Challenges: The moderate-to-hot heat and humid humidity of the Mid-Atlantic can create favorable conditions for fungal diseases like powdery mildew. Our even rainfall can also contribute to moisture-related problems. Keep a close eye on your Calendula, especially during the summer months, and take action promptly if you notice any signs of trouble.

Calendula makes a wonderful companion plant in the Mid-Atlantic garden. It attracts beneficial insects like ladybugs and lacewings, which prey on aphids and other pests.

Good companions include tomatoes and peppers, as Calendula can help protect them from pests. Green beans also benefit from Calendula's pest-repelling properties. There aren't any particularly bad companions to avoid, so feel free to plant Calendula wherever you need a little extra pest control or a pop of color.