How to Plant, Grow, and Care for Marigolds to Enjoy Their Bright Blooms

Marigolds are a typically easy and fast-growing bedding plant. Native to Mexico and Central America, marigolds thrive in hot and sunny conditions and are considered a beautiful addition to any garden. Along with being known for their bright, cheerful blooms, marigolds make excellent companion plants, attracting pollinators and deterring pests.

Depending on the species, marigolds can grow anywhere from 5 inches to 4 feet tall. As members of the Asteraceae family, these carnation- and daisy-like blooms can self-seed, which makes them appear as perennials. Most varieties, however, are annuals that grow well in most zones, from 2 through 11. Read on to learn more about planting and caring for marigolds in your garden.

How to Plant Marigolds

You can either plant marigolds from seeds or mature plants.

From Seed

You can plant marigold seeds indoors, about six to eight weeks before your last frost date. To start, sow seeds on the "surface of a tray or small pot filled with ordinary commercial potting soil that is lightly dampened," says Eric Groft, CEO and director of OvS and author of the gardening book Beyond Bold. Cover the seeds with a thin layer of vermiculite and then cover the whole tray or pot with plastic, he adds.

Marigold seeds do not need sunlight at this stage; simply setting your container in a warm area will make them sprout within four to five days after planting. Then, you can remove the plastic and move the container to a location that gets four or five hours of light each day, Groft says, advising to "keep the potting mix moist but not sopping," which prevents damping-off fungus. When your seedlings start showing new leaves, it's time to transplant your blooms outdoors.

As Mature Plants from a Garden Center

When working with mature plants, prepare a bed for your marigolds in a sunny, clean site in your garden (where water can drain quickly) at least two weeks before planting. The night before you put your marigolds in the ground, run water through them so it drains freely through every container base, hydrating each plant's foliage, stems, and root system.

Next, dig holes at least 8 to 10 inches apart (this guideline may vary based on your species) and remove your marigolds from their containers and untangle their roots. Place each marigold into your planting hole, and fill each crevice with soil until it reaches the base of its stem. Press the soil with your hands firmly, forming an even surface on top. Lastly, water to a 4-inch depth. Once established, your marigolds will multiply, even if you leave them unattended.

How to Grow Marigolds

Marigolds are fairly easy to grow, whether you're planting them in a garden bed or in your vegetable garden to deter pests.

Light

For an abundance of blossoms, it's best to plant your marigolds in full sun. Lowlight conditions will cause the plants to flower in smaller quantities.

Water

To further nourish your marigolds, water them regularly, especially when they are young. Groft cautions to never leave marigolds in dry soil for more than a few days. During periods of extreme heat, it's best to water new plants daily. However, once established, "marigolds will be more drought-tolerant, but will still bloom best if watered weekly," he says.

Fertilizer

"Marigolds do not need supplemental fertilizer unless your soil is extremely poor," says Groft. But, if you want to boost nutrition and support better drainage, you can always work in a layer of compost. Ultimately, the best way to maintain marigolds is by deadheading them regularly.

How to Care for Marigolds

Simple pruning will help keep your marigolds flowering throughout the entire season.

Pruning

Groft notes that pruning away early flower buds will cause a marigold plant to bush out, resulting in a lusher main blooming season. Deadheading, or removing spent flowerheads after they bloom, will also keep the plant producing new flowers well into the fall season.

Transplanting

Marigolds make for stunning outdoor container plants, due to their long-lasting color and texture. Plus, they respond well to transplanting and quickly establish new roots in soil. You can "use ordinary commercial potting soil in any kind of container, but clay pots are especially good," says Groft. "No repotting is necessary, as you'll be discarding the plant when the growing season concludes."

The Most Common Marigold Varieties

These are the marigold varieties you are most likely to encounter when at your local garden store or when searching for seeds. The variety you pick depends on your soil, sun, and your purpose for planting.

Tagetes erecta (African marigolds)

Commonly used as a bedding or container plant, African marigolds are characterized by their bright-yellow, pom-pom flowerheads, which can become quite large. This variety begins to bloom in early summer; with proper deadheading, they will continue to blossom well into fall. One of the taller marigold varieties, mature African plants can reach 3 feet.

Tagetes patula (French marigolds)

This species is shorter, reaching 1 foot in height at peak maturity; French marigolds prefer to spread horizontally, resulting in low, but more expansive ground cover. Their ruffled petals range from yellow and orange to brilliant red and russet. On the whole, this variety can withstand wetter conditions.

Tagetes tenuifolia (Signet marigolds)

While African and French marigolds are bushy and ruffled, Signet iterations are simpler, boasting just five heart-shaped leaves arranged around a sunburst center. Drought-tolerant and hardy, these blooms are deer- and rabbit-resistant—which is why they are commonly used to line fruit and vegetable gardens.

How to Identify and Treat Disease in Marigolds

Like most plants, marigolds are not immune to rots, blights, and mildews, including powdery mildew, a fungal disease. A telltale sign that your marigold is experiencing this ailment? If leaves have a white residue, fungal spores could be growing. But there is good news: Although it may take away from the plant's beauty, powdery mildew is seldom fatal.

Still, for the best disease prevention, continuously provide your marigolds with proper air circulation by ensuring there is ample room between plants. Watering them by "ground-soaking, rather than by overhead spraying," says Groft, should also help.

How to Identify and Fix Signs of Distress in Marigolds

Remember that most signs of marigold distress—like wilting, decay, or white spots—are caused by fungal spores, which is why air flow and correct watering practices are critical. To mitigate the infection, remove impacted plant materials, which can limit the spread of disease, Groft says. If all else fails, amend your soil with compost; add grit and sand to loosen the earth if you're working with heavy clay soil.

Wilting marigolds may also signal thirst. The best thing to do is assess your plant and water it regularly. Root rot can also cause wilting, so it's essential to stick to containers that drain well (don't use saucers), or well-draining soil if you're working in a bed.