Growing marigolds from seed: Tips for indoor and direct sowing

Marigolds were one of the first flowers I could identify as a kid. Growing up, my mom would plant marigold seeds along the side of our garage. I remember the strong scent as you’d brush by the bright yellow and deep orange blooms in the summer. Growing marigolds from seed is an easy way to add annuals to your gardens and containers. In this article, I’m going to share tips on sowing seeds indoors (and then moving your plants to the garden), as well as direct-sowing your marigold seeds in the spring.

There are over 50 different species of marigolds. The most popular include French marigolds (Tagetes patula) and African marigolds (Tagetes erecta). The flowers are used as decoration in various celebrations and religious events around the world. But don’t let the common names fool you. Marigolds are actually native to Central and South America. In fact, the Aztecs used them in Day of the Dead ceremonies. Signet marigolds (Tagetes tenuifolia) are another variety you may encounter. They have much smaller blooms that sit atop feathery foliage.

Taller marigold varieties make gorgeous cut flowers, while others are used as a natural dye for fabrics. Some marigolds are edible—and the flowers are used as natural food dyes—but be careful which variety you choose to eat as they don’t all have the best flavor!

Where to plant marigolds

Marigolds are often used as edging plants in garden beds and borders, planted in raised beds and vegetable gardens, and added to container arrangements. I plant them in all these scenarios, but mostly in my raised beds. Marigolds attract a number of pollinators, like bees and butterflies, to the vegetable garden.

Why grow marigolds from seed?

Marigolds are among those versatile annuals where you don’t buy just a plant or two, you buy a flat or two. They can often be found in plug trays or as larger, more developed seedlings. Growing the plants from seed can help you save money. You also don’t have to rely on the varieties the garden center has to offer. You can choose from among dozens of showy blooms and spend maybe about three dollars on a packet of seeds, rather than the same amount on just one small plant.

Growing marigolds from seed indoors

Read your seed packet as it will provide all the growing information you need. Generally you sow marigold seeds about four to six weeks before your last frost date. Fill your pot or seedling tray with lightly moistened seed starting mix (or make your own). I plant them in a small seedling tray with a couple of seeds per plug. Press seeds about a quarter of an inch (about half a centimetre) into the soil.

Place your seedling tray in a sunny window or under grow lights (I use the latter to start my marigolds). Use a spray bottle or mister to water (unless you have a self-watering container for seed starting).

Try to avoid over-watering young marigold seedlings. They can be prone to damping off, which is caused by a fungus or mold that can develop in overly wet conditions, killing the plant. Make sure there is air circulating between your seedlings, as well.

Hardening off and planting marigold seedlings

Hardening off your plants is an important step if you start marigold seeds indoors. It allows your plants to gradually acclimatize to the spring air after being in the house. Start by placing your seedling tray outdoors in a shady spot. Bring them in at night. Keep placing them in shade for about three or four days, and then you can start introducing them to gradual amounts of sunshine.

When you’re ready to plant, choose an area of the garden that gets full sun and has well-draining soil. Dig a hole about the size of the root ball of your seedling, fill in the hole around your plant, and use your watering can to water the base of the plant.

How far apart you space your marigolds will depend on the variety. You want to make sure there is space between plants for air flow. Add a layer of mulch around plants to keep the weeds down.

Using marigolds as companion plants to repel pests

As popular as marigolds are as companion planting suggestions, in Jessica’s book Plant Partners, she writes how there isn’t a lot of science to back up some of the traditional combinations. A lot of articles talk about how marigolds repel nematodes in the soil, which is why you’ll often see them planted in vegetable gardens. Though they are also planted to repel deer, rabbits, squirrels, and other four-legged pests.

Jessica does mention a study where marigolds were planted around onions. There was promising evidence that onion flies were laying less eggs at the base of allium plants. Similarly, when marigolds were planted around cole crops, there was less egg-laying behaviour from cabbage root maggot flies.

Growing marigolds from seed by direct sowing

Marigolds are sun worshippers that don’t like the cold. Sow seed after all danger of frost has passed. This will be after your last frost date, around the same time you plant your warm-weather veggies, like tomatoes, melons, and peppers.

Choose an area that gets full sun and has well-draining soil. Marigold plants don’t like constant moisture, but don’t mind poorer soils. Seeds take about five to 10 days to germinate, but once they get going, they grow pretty quickly, taking about eight weeks to bloom.

You can make a very shallow furrow in the soil, place seeds according to the distance indicated on the package directions, and then lightly cover the seeds. Or, press seeds about a quarter of an inch (about half a centimetre) into the soil. Water very lightly until seedlings have become established.

If you see a sudden frost in the forecast, cover your plants with a cloche, floating row cover, or even a light bedsheet. I’ve lost transplants in May because I forgot to cover them before a night where temperatures unexpectedly dipped way below normal.

Caring for marigold plants

Deadheading spent flowers from your marigold plants throughout the season will encourage more blooms. It’s not totally necessary, but keeps the plant looking fresh, especially those with big blooms that will start to drop rotting, soggy petals as they decompose.

If you’ve planted any of the taller varieties of marigolds, strong winds can blow the stems over, so you may need to stake your plants. Avoid issues like root rot and mold by ensuring your marigolds are planted in well-draining soil.

More annuals to grow from seed

• How to grow Salpiglossis: The painted tongue flower
• Zinnia Profusion: Grow an abundance of these gorgeous annual flowers in gardens and containers
• Growing sweet alyssum from seed: Add this bloom-filled annual to raised beds, gardens, and pots
• When to plant sunflowers: Three options for lots of beautiful blooms
• How to plant and grow a cut flower garden