Calendula in Zone 7B — Pacific Northwest

Calendula is a fantastic addition to any Pacific Northwest garden. Its bright, cheerful flowers add a pop of color, and they're also edible with a slightly peppery taste. Plus, Calendula attracts beneficial insects and the cool nights we get here actually intensify the flavor.

While we might struggle a bit with heat-loving plants, Calendula thrives in our mild summers. Our 193-day growing season gives you plenty of time to enjoy its blooms, especially if you get a jump start in early spring.

Starting Calendula indoors isn't strictly necessary in our region, but it can give you a head start, especially if you're eager for early blooms. If you choose this route, sow seeds indoors from mid-February through early March, about six weeks before you plan to transplant.

Use seed trays filled with a good seed-starting mix. Keep them warm and provide plenty of light – a simple shop light works well. Water gently from the bottom to avoid damping off, which can be a problem in our often overcast spring days.

Transplant your Calendula seedlings outdoors from early April through mid-May, once the danger of hard frost has passed. Before planting them in the ground, harden them off by gradually exposing them to outdoor conditions for about a week.

Choose a sunny spot with well-drained soil, and space the plants 8-12 inches apart to allow for good air circulation. Keep an eye on the weather forecast; a late cold snap can still happen, so be ready to cover your seedlings if necessary.

Direct sowing Calendula seeds is a simple and effective method in the Pacific Northwest. You can sow seeds directly into the garden from early April through late August. This gives you a long window to stagger plantings for a continuous supply of flowers.

Prepare the soil by loosening it and removing any weeds. Sow seeds about a half-inch deep, and space them 8-12 inches apart. Keep the soil consistently moist until the seedlings emerge, which usually takes about a week or two.

Calendula prefers moderate watering, which fits well with our typical Pacific Northwest climate. While they can tolerate short periods of drought, they'll thrive with consistent moisture, especially during our dry summer months.

During the wet springs, you may not need to water at all, but once the dry summer hits, check the soil regularly. Stick your finger about two inches deep into the soil; if it feels dry, it's time to water. Aim for about an inch of water per week, watering at the base of the plant to avoid wetting the foliage, which can encourage powdery mildew.

Overwatering can lead to root rot, so watch for yellowing leaves. Underwatering will cause the plant to wilt. A layer of mulch, like composted leaves, will help retain moisture and suppress weeds.

Deadheading is key to keeping your Calendula plants blooming throughout the season. Regularly remove spent flowers to encourage the plant to produce more buds. Simply pinch or snip off the flower heads just below the bloom.

Leave a few flowers to mature if you want the plant to self-seed. As the first frost approaches in late October, you can either let the plants die back naturally or collect the seeds for next year's planting.

You can expect your first Calendula harvest starting in mid-May, about 45 days after sowing, and continue harvesting through early November. Pick the flowers when they are fully open, ideally in the morning after the dew has dried.

Gently snip the flower heads from the stem, taking care not to damage the surrounding foliage. Continued harvesting encourages more blooms. Even as the first frost looms in late October, you can often still harvest flowers, though their production will slow down.

Even in the relatively pest-free Pacific Northwest, Calendula can sometimes encounter a few problems. Here's what to watch out for:

Powdery Mildew

• What it looks like: A white or grayish powdery coating on leaves and stems. Leaves may curl, yellow, and eventually die.
• What causes it: Fungi that thrive in warm days, cool nights, and moderate humidity. Ironically, dry leaf surfaces are favorable, which can be an issue during our dry summer months.
• How to fix/prevent it: Improve air circulation by spacing plants properly and pruning if necessary. Remove affected leaves. Neem oil or potassium bicarbonate sprays can help. A milk spray (1 part milk to 9 parts water) is also effective.

Aphids

• What it looks like: Clusters of tiny green, black, or white insects on stems and leaf undersides. You might also see sticky honeydew residue and curled or distorted new growth.
• What causes it: Rapidly reproducing sap-sucking insects. Their populations can explode during warmer spells.
• How to fix/prevent it: Knock them off with a strong spray of water. Encourage natural predators like ladybugs. Insecticidal soap or neem oil can be used for heavier infestations.

Whiteflies

• What it looks like: Tiny white, moth-like insects that fly up in a cloud when disturbed. Yellowing leaves. Sticky honeydew residue.
• What causes it: Sap-sucking insects that thrive in warm, sheltered conditions.
• How to fix/prevent it: Hang yellow sticky traps to catch adults. Vacuum them off plants. Insecticidal soap or neem oil can be effective, especially when applied regularly.

Pacific Northwest Specific Challenges: Our mild heat and dry-summer rainfall generally benefit Calendula, but late blight can still be a concern, particularly if your Calendula is planted near tomatoes or potatoes. Good air circulation and avoiding overhead watering can help prevent it. Slugs can also be an issue, especially in the spring; use slug bait or traps to protect young plants.

Calendula makes a wonderful companion plant in the Pacific Northwest garden. Planting it near tomatoes and peppers can help deter pests like tomato hornworms and aphids. Calendula attracts beneficial insects like ladybugs and hoverflies, which prey on these pests.

Calendula is also a good companion for green beans. It can help repel bean beetles, which can be a nuisance in our region. Avoid planting Calendula near members of the cabbage family, as it can attract cabbage moths.