How to Properly Plant Marigold Seeds for Spring
Start Marigolds Indoors or Direct Seed Them in Your Garden
Marigolds are one of the most popular annuals to grow from seed because starting them from seed is so easy. The seeds are large and easy to handle, and you don’t have to wait long for them to germinate. No wonder marigolds are a favorite flower to plant with kids, either at home or in school projects.
When to Sow Marigold Seeds
As tropical or semi-tropical plants, marigolds don’t like the cold. When direct sowing them in your garden, wait at least one, better two weeks after the final spring frost. Indoors, you can start them much earlier, about six to eight weeks before the average last frost date in your area.
Why Marigolds Are Beneficial in Vegetable Gardens
Whether you plant African marigolds or French marigolds, these cheerful flowers do lots of good things for your vegetable garden. The vibrant yellow or orange flowers attract pollinators such as bees, butterflies, and hummingbirds. Marigolds also attract beneficial insects such as lacewings, ladybeetles, and parasitic wasps.
Planting marigolds helps to suppress root-knot nematodes and some fungi, bacteria, insects, and viruses. Nematodes are microscopically small roundworms that damage the roots of plants but marigolds produce alpha-terthienyl, a chemical whose compounds are toxic to root-knot nematodes and other plant disease organisms.
The pungent odor of the marigold foliage deters deer and rabbits so planting them around vulnerable crops can help protect them.
What You'll Need
Equipment / Tools
- Gardening gloves
- Grow lights (optional)
- Watering can, spray bottle, or hose
- Marigold seeds
- Seed trays or 3 1/2-inch seed-starting pots (optional)
- Potting mix (optional)
How to Direct Sow Marigold Seeds
Wait at least one week after the last frost date to plant marigold seeds. An average soil temperature of 70 to 75 degrees Fahrenheit is ideal for germination.
Select a sunny spot that gets at least six to eight hours of direct sunlight. In soil that is free of weeds and large rocks, place the seeds one inch apart on the soil surface and press them down firmly. Marigold seeds require light to germinate, so cover the seeds with only a very thin layer of soil, not thicker than 1/16 inch.
Gently water the seeded area with a watering can, spray bottle, or a hose with a sprayer head set to low. Keep the soil evenly moist and water if it doesn’t rain. Seeds will germinate in four to 14 days.
Once the seedlings emerge, start thinning them by cutting unwanted seedlings at ground level with scissors. Don’t remove all the extra seedlings at once but do it gradually as they grow and start to overcrowd each other. The goal is space of eight to 10 inches between small varieties such as French marigolds, and at least 10 to 12 inches between the larger African varieties.
How to Start Marigold Seeds Indoors
Because marigolds germinate quickly outdoors, starting them indoors has no real advantages over direct sowing them in the garden—unless you live at the lowest end of the zone range for marigolds (USDA zones 2-11) where summers are very short. Also keep in mind that you need to give them lots of light (a large sunny window or grow lights), otherwise the seedlings will get leggy.
Six to eight weeks before your last average frost date, fill pots or a seedling tray with potting mix or seed starting mix and thoroughly spray the medium with water so it’s lightly dampened all the way through.
Sow three to four seeds in each seed-starting pot. Gently press the seeds on the surface of the soil and cover with no more than 1/16 inch of potting mix or seed starting mix.
To retain the soil moisture, you can cover the tray or pots with clear plastic (optional).
Place the tray or pots in them a warm location where the temperature is about 65 to 75 degrees Fahrenheit during the day and about the same temperature at night. Place them under grow lights or near a bright south-facing window.
Once the seeds have germinated, remove the plastic and continue to keep the soil moist but not sopping wet.
As the seedlings start to grow, thin them out to one to two per pot by cutting them at soil level.
When the seedlings start to vigorously grow leaves, gradually harden them off before transplanting them outdoors once all danger of frost has passed.
Which side of marigold seed goes down?
Place the seeds on the soil horizontally, which is mimicking the way the seeds naturally fall out of the seed capsule. There is no top or bottom end to marigold seeds.
What month do you plant marigold seeds?
It depends on your zone and whether you start them indoors or outdoors. Always plant your marigolds in the spring after the last frost. If you choose to start them from seed indoors, you can begin the process six to eight weeks before the last expected frost.
How many marigold seeds should you plant together?
Place groups of three or four seeds together, with about one-inch space between them. Space these seed clusters six to 12 inches apart, depending on the type of marigold. French marigolds are smaller and need less space and African marigolds are taller and need more space.
Using Flowering Plants to Help Parasitic Wasps Attack Stink Bug Eggs. University of Maryland Extension.
Marigolds and Nematode Management. Arizona Cooperative Extension.