French Marigold in Zone 6A — Pacific Northwest

French Marigolds are a fantastic choice for adding vibrant color and deterring pests in your Pacific Northwest garden. Their cheerful blooms brighten up any space, and their scent is known to repel certain unwanted insects from your precious veggies. Plus, the cool nights we often get here seem to intensify their fragrance, making them even more enjoyable.

Our mild summers and wet springs can present some challenges, but French Marigolds are surprisingly adaptable. With a growing season of around 148 days, you have plenty of time to enjoy their beauty. Careful timing helps you avoid the worst of the spring dampness and take advantage of our dry summer months.

Starting French Marigolds indoors in our region is optional, but it can give you a head start, especially if you're aiming for early blooms. Start your seeds indoors from early to late April, roughly six weeks before you plan to transplant them outside. This is helpful if you want to get your flowers blooming before the dry summer months.

Use seed trays or small pots filled with a good seed-starting mix. Provide warmth, either with a heat mat or by placing them in a warm spot in your home. Once the seedlings emerge, make sure they get plenty of light – a grow light is ideal, especially with our often overcast spring days. Water from the bottom to avoid damping off.

Transplanting French Marigolds outdoors is best done from late May through early July, after the risk of frost has passed. Before transplanting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week. This prevents transplant shock.

Choose a sunny spot with well-drained soil. Space the plants 8-10 inches apart to allow for good air circulation. Keep an eye on the weather forecast – if a late cold snap is predicted, be prepared to cover your young plants.

Direct sowing French Marigolds is a perfectly viable option in the PNW. It's less work than starting indoors, and the plants will quickly catch up once the soil warms up. Direct sow your seeds from early May through early August for blooms all season.

Prepare the soil by loosening it and removing any weeds. Sow seeds about ¼ inch deep and keep the soil consistently moist until they germinate. Thin seedlings to 8-10 inches apart once they have a few sets of true leaves.

French Marigolds are quite drought-tolerant once established, making them a good choice for our mild, dry summers. However, they do need consistent watering, especially when young. The goal is to keep the soil consistently moist, but not waterlogged.

During our wet springs, you likely won't need to water them much at all. Once the dry summer months arrive, check the soil regularly. Stick your finger about 2 inches deep; if it feels dry, it's time to water. Aim for about 1 inch of water per week, either from rainfall or irrigation. Water at the base of the plants to avoid wetting the foliage, which can encourage fungal diseases.

Signs of underwatering include wilting leaves and stunted growth. Overwatering can lead to root rot, indicated by yellowing leaves and a generally unhealthy appearance. A light layer of mulch around the base of the plants can help retain moisture and suppress weeds.

Deadheading is key to keeping your French Marigolds blooming profusely throughout the season. Regularly remove spent flowers to encourage the plant to produce more blooms. Simply pinch or cut off the flower heads just below the spent bloom.

Continue deadheading throughout the summer and into the fall. As the first frost approaches around early October, you can let the last flowers go to seed if you want to collect them for next year. Otherwise, remove the plants after the first hard frost.

You can expect your first French Marigold blooms around late June if started indoors, or a bit later if direct sown. They’ll continue blooming all the way through early October. Harvest the flowers when they are fully open for the most vibrant color and fragrance.

To harvest, simply cut the stem just above a leaf node. This will encourage the plant to produce more flowers from that point. For continuous production, keep deadheading spent blooms and harvesting new flowers regularly.

As the first frost approaches in early October, harvest any remaining blooms you want to enjoy indoors. You can also allow some flowers to dry on the plant to collect seeds for next year's garden.

Here are a few potential problems to watch out for with French Marigolds in the PNW:

Spider Mites

• What it looks like: Fine webbing on the leaves and tiny, spider-like creatures crawling around. Leaves may appear stippled or yellowed.
• What causes it: Hot, dry conditions can encourage spider mite infestations. They thrive in dry-summer humidity.
• How to fix/prevent it: Increase humidity around the plants by misting them regularly. A strong spray of water can dislodge spider mites. Insecticidal soap or neem oil can also be effective.

Powdery Mildew

• What it looks like: White or grayish powdery coating on leaves, stems, and sometimes buds. Leaves curl, yellow, and die.
• What causes it: Powdery mildew is caused by various 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 if necessary. Remove affected leaves promptly. Neem oil or potassium bicarbonate sprays can help. A milk spray (1 part milk to 9 parts water) is surprisingly effective.

Slugs

• What it looks like: Holes in the leaves of young plants, and slime trails on the soil surface. You might even catch them in the act!
• What causes it: Slugs are a common pest in the PNW, especially during our wet springs. They love tender seedlings.
• How to fix/prevent it: Use slug bait, beer traps, or handpick them off the plants, especially at night. Copper tape around the base of plants can also deter them.

Pacific Northwest Specific Challenges: Our mild heat and dry-summer rainfall patterns generally favor French Marigolds. However, be vigilant about spider mites during particularly dry spells, and take precautions against slugs, especially when plants are young.

French Marigolds are great companion plants for several reasons. They release compounds into the soil that can deter nematodes and other soil pests.

Good companions include tomatoes, peppers, and basil. Marigolds deter pests that bother tomatoes and peppers, while basil helps repel tomato hornworms. Cucumbers also benefit from marigolds repelling cucumber beetles. Green beans can benefit, but marigolds can also attract spider mites which beans are susceptible to.