Calendula in Zone 10B — Florida

Calendula is a fantastic addition to any Florida garden, offering vibrant color, edible petals, and medicinal properties. The slightly peppery taste of the petals brightens salads and soups, and the bright orange and yellow hues are a welcome sight during our fall-through-spring growing season when many other flowers are taking a break.

While Florida gardening presents challenges like humidity and nematodes, Calendula thrives during our cooler months, making it a rewarding crop to grow. With our nearly year-round growing season, you can enjoy these cheerful blooms for a significant portion of the year if you time it right.

Starting Calendula indoors in Florida is possible, but honestly, it's usually not necessary unless you want a really early start. If you're set on it, begin in early to late November, about six weeks before you plan to transplant. Use seed trays with a good seed-starting mix, provide gentle warmth, and ensure adequate light – a simple grow light works well.

Consider bottom watering to keep the soil evenly moist without overwatering the seedlings, which is especially important in our humid climate. Starting indoors gives you a slight head start, but direct sowing is so easy that many of us skip this step. Remember our spring character is reversed, so aim to transplant as the weather starts to cool down, not warm up.

Transplant your Calendula seedlings outdoors in late December through early February, once they have a few sets of true leaves. Before transplanting, harden them off by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the Florida sunshine and humidity.

Space the plants about 8-12 inches apart to allow for good air circulation. Keep an eye on the weather forecast; even though we rarely get hard freezes, a sudden cold snap can stress young transplants. Protect them with a frost cloth if necessary.

Direct sowing Calendula is very easy in Florida. You can sow seeds directly into your garden beds from late December through early November. Calendula seeds germinate best when the soil temperature is between 60-70°F, which aligns perfectly with our cooler months.

Prepare the soil by loosening it and adding some compost to improve drainage. Sow seeds about ¼ inch deep and space them 8-12 inches apart. Keep the soil consistently moist until the seedlings emerge, which usually takes about a week. Direct sowing saves time and effort, and the plants often catch up quickly to those started indoors.

Watering Calendula in Florida requires a bit of finesse due to our unique climate. During the cooler, drier months (late fall through early spring), water deeply whenever the top two inches of soil feel dry to the touch. This is easily checked with the "finger test." Aim for about 1 inch of water per week, either from rainfall or irrigation.

As the weather warms up in late spring, monitor the soil moisture more closely. While Calendula tolerates some drought, it prefers consistent moisture. During our wet-summer months, be careful not to overwater. The extreme humidity combined with frequent rainfall can quickly lead to root rot and fungal diseases. Water at the base of the plants to avoid wetting the foliage, which encourages fungal growth.

Signs of underwatering include wilting leaves and stunted growth. Overwatering can cause yellowing leaves and root rot. A layer of mulch, like pine straw or wood chips, can help retain moisture in the soil and suppress weeds, but be sure to keep it away from the plant's base to prevent rot. Remember, Calendula may go dormant during the hottest parts of summer, so reduce watering during this period.

Pruning Calendula is straightforward and essential for continuous blooming. Deadheading, or removing spent flowers, is the key to encouraging the plant to produce more blooms. Simply pinch or cut off the flower heads as soon as they start to fade.

Throughout the growing season, regularly deadhead to keep the plant tidy and productive. If you want Calendula to self-seed, allow some flowers to mature and form seed heads. As our first frost approaches around late December, you can either let the plants go to seed or cut them back to encourage new growth if the weather stays mild.

You can expect your first Calendula harvest in early February through early January, 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. The petals are most potent when the flowers are at their peak.

To harvest, simply cut the flower heads off the stem using scissors or pruning shears. Be gentle to avoid damaging the plant. Regular harvesting encourages continued production of new flowers.

As the first frost approaches in late December, you can harvest all remaining flowers and dry them for later use. Alternatively, if the weather stays mild, you can cut the plants back to encourage a new flush of growth. The seeds form in the dried flower heads, so you can collect those to sow for the next season.

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

Powdery Mildew

• What it looks like: White or grayish powdery coating on leaves, stems. Leaves curl, yellow, and die.
• What causes it: Fungi that thrive in warm days, cool nights, and moderate humidity. Dry leaf surfaces actually favor it.
• 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) can be effective. Plant resistant varieties.

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. Avoid excess nitrogen fertilizer.

Whiteflies

• What it looks like: Tiny white, moth-like insects that fly up when disturbed. Yellowing leaves. Sticky honeydew residue.
• What causes it: Sap-sucking insects that thrive in warm, humid conditions.
• How to fix/prevent it: Yellow sticky traps. Strong water spray. Insecticidal soap or neem oil. Reflective mulch can deter them.

Florida Specific Challenges: Our hot heat, very-high humidity, and wet-summer rainfall create a breeding ground for fungal diseases and pests that can impact Calendula. Proper spacing, good air circulation, and vigilant monitoring are crucial for success. During the rainy season, be extra cautious with watering to prevent root rot.

Calendula makes a great companion plant in Florida gardens. It attracts beneficial insects that can help protect other crops.

Good companions:

• Tomatoes: Calendula repels tomato hornworms and other pests.
• Peppers: Calendula attracts beneficial insects that prey on pepper pests.
• Green beans: Calendula helps deter bean beetles.

Avoid planting Calendula near plants that are susceptible to the same pests or diseases, but there aren't any specific bad companions to be particularly concerned about.