French Marigold in Zone 8B — Pacific Northwest

French Marigolds are fantastic for our Pacific Northwest gardens. Their bright blooms bring cheer and are edible, adding a peppery kick to salads. They're also great companions for veggies, helping to keep pests away. Plus, they thrive in our mild summers and cool nights.

While we sometimes struggle with cool soil in spring and late blight can be a concern, the timing for growing French Marigolds fits perfectly within our 210-day growing season. You'll find success with these cheerful flowers.

Starting French Marigolds indoors gives you a jumpstart, but it's not always necessary here in the PNW. If you want blooms extra early, aim to sow seeds indoors from early to late March, about six weeks before you plan to transplant.

Use seed trays with a good seed-starting mix. Provide warmth and plenty of light – a grow light works wonders, especially with our overcast spring days. Bottom watering helps prevent damping off; set the tray in a shallow dish of water until the soil surface is moist.

Transplant your French Marigold seedlings outdoors from mid April through late May, once the danger of frost has passed. Before planting, harden them off by gradually exposing them to outdoor conditions for about a week.

Space them 8-10 inches apart in a sunny spot. Keep an eye on the weather; a late cold snap can still happen, so be ready to cover them if needed.

Direct sowing French Marigolds is an easy option in our climate. Wait until the soil warms up a bit, usually from early April through late August.

Prepare the soil by loosening it and removing any weeds. Sow seeds 8-10 inches apart, cover lightly with soil, and keep them consistently moist until they germinate. Direct sowing is less work, but you'll get blooms a bit later than starting indoors.

French Marigolds are relatively drought-tolerant once established, which is great for our dry summer months. During the wet springs, you may not need to water them at all. Let the rainfall do its job!

Once the dry summer months arrive, check the soil moisture by using the "finger test." Stick your finger about two inches deep into the soil; if it feels dry, it's time to water. Aim for about one inch of water per week during dry spells.

Water at the base of the plants to avoid wetting the foliage, as this can encourage fungal diseases. Overwatering can lead to root rot, so watch for yellowing leaves. Underwatering will cause wilting. A light layer of mulch can help retain moisture and suppress weeds.

Deadheading is key to keeping your French Marigolds blooming all season long. Regularly remove spent flowers by snipping them off just below the flower head.

This encourages the plant to produce more blooms instead of putting energy into seed production. As the first frost approaches in early November, you can let the last flowers fade and dry to collect seeds for next year.

You can expect your first French Marigold harvest starting in late May and continuing through early November, about 50 days after planting. Harvest the flowers when they are fully open for the best flavor and color.

To harvest, simply snip the stem just below the flower head with clean scissors or pruners. Regular harvesting encourages continuous blooming. Towards the end of the season, let some flower heads dry on the plant to collect seeds for next year.

Here are a few common problems you might encounter with French Marigolds in the Pacific Northwest:

Spider Mites

• What it looks like: Fine webbing on the leaves and tiny, moving specks. Leaves may appear stippled or bronzed.
• What causes it: Dry, hot conditions can encourage spider mite infestations.
• How to fix/prevent it: Increase humidity around the plants by misting them with water. Insecticidal soap or neem oil can also help control infestations.

Powdery Mildew

• What it looks like: White or grayish powdery coating on leaves, stems, and sometimes flower heads. Leaves may 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 by spacing plants properly and pruning. Remove affected leaves. Neem oil or potassium bicarbonate sprays can help. Milk spray (1 part milk to 9 parts water) is also effective.

Slugs

• What it looks like: Holes in leaves, especially on young plants. Slimy trails on and around the plants.
• What causes it: Slugs thrive in our damp, overcast spring conditions.
• How to fix/prevent it: Use slug bait, beer traps, or handpick slugs off the plants in the evening. Copper tape around the base of plants can also deter them.

Pacific Northwest Specific Challenges: Our mild heat and dry-summer rainfall generally favor French Marigolds. However, be vigilant about spider mites during particularly dry spells and watch out for slugs in the wet springs. Late blight is less of a direct threat to marigolds, but good garden hygiene helps prevent its spread.

French Marigolds are excellent companion plants in the Pacific Northwest. Plant them near tomatoes and peppers to deter nematodes and other pests. Their scent also repels aphids from basil and cucumbers.

Avoid planting them near green beans, as they can sometimes inhibit bean growth. Overall, French Marigolds are a beneficial addition to any PNW vegetable garden.