When to Plant Marigolds: Seed-Starting and Planting Dates by Frost

Marigolds (Tagetes) come from Mexico and Central America, and they bloom from early summer until a hard frost (Clemson, University of Minnesota). They grow fast from seed, which makes them one of the easiest flowers to time (Clemson). The main types differ in size: French marigolds are compact, about 6 to 12 inches tall; African marigolds reach 3 to 4 feet; signet marigolds stay about 6 inches or less (University of Minnesota).

Planting dates by last frost

The table counts from your average last spring frost. Indoor dates follow Clemson. Plant transplants outside once the danger of frost has passed. Direct sowing waits for warm soil: University of Minnesota sows once the soil reaches 65°F, which in most gardens is about 1 to 3 weeks after the last frost. That last column is GardenPal's estimate, so check with a soil thermometer if you have one.

Starting marigolds from seed

Sow seed about ¼ inch deep and keep it covered and moist (Clemson, University of Minnesota). At 70 to 75°F, seeds come up in about 5 to 8 days (University of Minnesota; Clemson says 5 to 7). After they sprout, University of Minnesota grows seedlings at about 65 to 75°F by day and 65 to 70°F at night. Pinching the tip of a young plant makes it branch and grow bushier (University of Minnesota).

Florida and warm climates

UF/IFAS Gardening Solutions says French marigolds do well year-round in Florida, while large-flowered African types are best planted for spring. In South Carolina, Clemson plants after the last spring frost and notes that most varieties bloom from early summer into late fall. In long, hot summers, choose heat-tolerant series; Clemson names the 'Big Duck' African hybrids as extremely heat tolerant.

Planting and spacing

Care through the season

Remove faded flowers to keep new ones coming and to stop old blooms from rotting in humid weather (University of Minnesota, Clemson). Stake tall African types so storms don't knock them over (Clemson). NC State notes that marigold sap can irritate skin, especially in sunlight, so gloves are a good idea if you deadhead a lot.

Pests and diseases

Marigolds have few serious problems, but they are not pest-proof. Clemson lists spider mites (worst in hot, dry weather), slugs, leafminers, aphids, whiteflies, thrips and caterpillars, plus gray mold and aster yellows. NC State adds Japanese beetles.

Marigolds in the vegetable garden

Marigolds are often planted with vegetables for pest control. The evidence is narrower than the folklore: some French marigold cultivars can suppress root-knot nematodes when grown as a dense cover crop, but interplanting a few marigolds among vegetables has not been shown to protect nearby plants (Clemson, UF/IFAS). See what to plant with marigolds for listed companions and how to use them as a cover crop, and companion planting for pest control for what the research supports.

Frequently asked questions

When should I plant marigolds outside?

After your last spring frost (Clemson). Larger transplants can go out once the danger of frost is gone, and seed can be sown directly once the soil reaches about 65°F (University of Minnesota).

When should I start marigold seeds indoors?

Clemson starts French marigolds 4 to 6 weeks before planting out and African marigolds about 8 weeks before. University of Minnesota allows about 10 weeks.

Can you direct sow marigolds?

Yes. They sprout quickly and are easy from seed (Clemson). Sow about ¼ inch deep once the soil has warmed and frost danger has passed.

How long do marigold seeds take to germinate?

About 5 to 7 days (Clemson) or 5 to 8 days at 70 to 75°F (University of Minnesota).

When do you plant marigolds in Florida?

UF/IFAS says French marigolds can be grown year-round in Florida, while large-flowered African types are best for spring.

How far apart should marigolds be planted?

French marigolds 8 to 10 inches apart and African marigolds 12 to 16 inches apart (Clemson).

Do marigolds keep pests away from vegetables?

Only in a limited way. Certain French marigold cultivars grown as a dense cover crop can suppress root-knot nematodes, but scattering marigolds among vegetables has not been shown to protect them (Clemson, UF/IFAS).