Calendula in Zone 9A — Gulf Coast

Calendula is a winner for us Gulf Coast gardeners. The bright, cheerful flowers are not only beautiful, but the petals are edible and have medicinal uses. Plus, it's super satisfying to grow something that blooms for such a long time in our long growing season.

Sure, we have our challenges with the high humidity and disease pressure down here. But with smart timing and attention to airflow, you can definitely enjoy a beautiful and bountiful Calendula harvest in your Gulf Coast garden. Our 303-day growing season gives you plenty of opportunity to get it right.

Starting Calendula indoors is definitely an option, but honestly, it's usually not necessary for us here on the Gulf Coast. Our early spring means you can direct sow for a head start. But if you want to get a jump on things, or if you're just itching to garden during those cooler months, you can start seeds indoors.

Start seeds indoors early to late December, about six weeks before you plan to transplant. Use seed trays with good drainage, and keep them in a warm spot with plenty of light – a sunny windowsill or under grow lights. Bottom watering helps prevent damping off, which can be a problem in our humid climate.

If you started your Calendula indoors, you can transplant them outdoors late January through early March. This gives them a chance to get established before the real heat hits.

Before transplanting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week. Plant them 8-12 inches apart in well-draining soil. Keep an eye on the weather – those late cold snaps can still happen, so be ready to cover them if needed.

Direct sowing Calendula is a breeze here on the Gulf Coast. You can sow seeds directly into the garden late January through mid October. This wide window allows for succession planting and a continuous supply of blooms.

Prepare your soil by loosening it and removing any weeds. Sow seeds 8-12 inches apart and cover them lightly with soil. Keep the soil consistently moist until the seedlings emerge. Just make sure the soil isn't too cold, or they may not germinate well.

Calendula likes moderate watering, which can be tricky in our Gulf Coast climate. They don't like to dry out completely, but they definitely don't like soggy feet, especially with our high humidity. They can handle a bit of drought, but they thrive best when it's cooler.

During the cooler months of late winter and early spring, and again in the fall, water deeply about once a week, or whenever the top two inches of soil feel dry to the touch – that's the "finger test." During our hot, humid summers, Calendula might go dormant or slow down their blooming. Water less frequently during this time, only when the soil is dry. We get plenty of rainfall here (50-65 inches per year), so you might not need to water at all during some weeks.

Water at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases in our humid environment. Aim for about an inch of water per week. Signs of underwatering include wilting leaves, while yellowing leaves can indicate overwatering. Mulching around your Calendula plants with pine straw or shredded leaves helps retain moisture and suppresses weeds, but keep the mulch away from the stem to prevent rot.

Deadheading is key to keeping your Calendula plants blooming throughout our long growing season. Pinch off the spent flowers regularly to encourage new buds to form.

Simply snip off the flower heads just below the bloom, leaving the stem and leaves intact. You can deadhead throughout the entire growing season, from spring through fall. As the first frost approaches in early December, you can let some of the last flowers mature and go to seed if you want them to self-sow for next year.

You can expect your first Calendula harvest about 45 days after planting, which means mid March through mid December is harvest time. The flowers are ready to harvest when they are fully open.

Gently pluck the entire flower head from the plant. For continued production, harvest regularly to encourage more blooms. As the first frost approaches in early December, harvest any remaining flowers before they get damaged by the cold. You can dry the petals for later use in teas, salves, or culinary dishes.

Here are some common problems you might encounter with Calendula in our Gulf Coast gardens:

• 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. Dry leaf surfaces actually favor it, which is why even with our humidity, it can still occur.
• How to fix/prevent it: Improve air circulation through spacing and pruning. Remove affected leaves. Neem oil or potassium bicarbonate sprays help. 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. 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.
• Whiteflies
• What it looks like: Tiny white, moth-like insects that fly up when disturbed. Yellowing leaves. Sticky honeydew.
• What causes it: Thrive in warm, humid conditions, like our Gulf Coast summers. They suck plant sap, weakening the plant.
• How to fix/prevent it: Yellow sticky traps can catch them. Strong water spray. Insecticidal soap or neem oil. Reflective mulch can deter them.

Gulf Coast Specific Challenges: Our hot heat and very-high humidity create a perfect breeding ground for fungal diseases and pests. Be vigilant about monitoring your plants and take action quickly to prevent problems from getting out of control. Also, we can get a lot of rain, which can lead to soggy soil and root rot. Make sure your soil is well-draining, and consider growing Calendula in raised beds if your area is prone to flooding.

Calendula is a great companion plant for many vegetables in the Gulf Coast garden. It attracts beneficial insects and helps repel pests.

Good companions:

• Tomato: Calendula repels tomato hornworms and other pests.
• Pepper: Deters aphids and other pests that attack peppers.
• Beans-green: Attracts pollinators and can help improve soil health.

Avoid planting Calendula near nothing that will compete for resources. With our long growing season, your Calendula will be happy and productive as long as it has space to thrive.