Germination temperature
About 21-24 °C (70-76 °F); outdoors sow once soil is above about 18 °C (65 °F).
Flower growing guide
French marigolds are compact, quick and tolerant of heat, and the seed sprouts within days at 22-24 °C. This guide covers sowing, the three Indian growing seasons, and how to keep plants flowering and healthy.
About 21-24 °C (70-76 °F); outdoors sow once soil is above about 18 °C (65 °F).
Shallow: a thin covering of compost or vermiculite.
Roots in 2-3 days; seedlings usually up in about 4-5 days.
Not required; light cover is fine, and good light after sowing gives sturdier seedlings.
None needed.
Both work; nursery-raised seedlings transplant easily.
Marigold seeds are long and thin with a pale tip. Sow them dry, lying flat, and space them so each seedling has room.
Not needed. The seed absorbs water quickly.
Not needed. French marigold is a warm-season annual with no cold requirement.
Not needed. Sow into moist compost and water gently.
Professional growers germinate French marigold at 22-24 °C (72-76 °F), then lower it to 20-21 °C (68-70 °F) after about a week. Outdoors, sow once temperatures are above about 18 °C (65 °F).
Cover the seed with a thin layer of fine compost or vermiculite, just enough to keep it moist.
A fine, well-drained seed compost or a raised nursery bed. Avoid wet, heavy mixes: damping off is a common nursery disease of marigolds.
Keep evenly moist but never waterlogged. Overwatering in the seedling stage invites damping off.
French marigold does not need light to germinate, so a light covering is fine. Move trays into good light as soon as seedlings appear to prevent stretching.
At 22-24 °C (72-76 °F) roots emerge in 2-3 days; in an Indian nursery bed seedlings usually appear in about 4-5 days.
In warm Indian conditions nursery seedlings are ready in 3-4 weeks, at about the 4-leaf stage and 10-12 cm (4-5 in) tall. In cooler climates, gardeners start seed indoors about 8 weeks before planting out after the last frost.
Pinch out the growing tips of young plants for a bushier habit. French marigolds grow about 15-30 cm (6-12 in) tall and need closer spacing than tall African marigolds.
Full sun, well-drained soil at about pH 6-7, and moderate, even moisture. Marigolds need little fertiliser; too much gives leaves rather than flowers.
Cause: damping off, from wet compost and poor drainage. Fix: use clean, free-draining compost, water lightly and give seedlings good air movement.
Cause: Botrytis in humid, rainy weather. Fix: water early in the morning at the base, deadhead regularly and avoid overcrowding.
Cause: spider mites in hot, dry weather. Fix: check leaf undersides, rinse plants with water and keep them from drought stress.
Cause: caterpillars such as Helicoverpa, serious on the Indian plains from March to April, or thrips. Fix: inspect plants often, hand-pick caterpillars and use pheromone or blue sticky traps.
On the plains marigolds are grown in three seasons: a winter crop sown around mid-September, a rainy-season crop sown around June, and a summer crop sown in January under protection. In the hills, sowing moves later the higher you go, into late spring at high elevations.
French marigolds flower from spring into autumn in temperate gardens if kept deadheaded; removing old blooms also reduces disease.
French marigold roots release alpha-terthienyl, which is toxic to root-knot nematodes. Grown as a dense cover in a bed and dug in, they can help reduce these pests before a vegetable crop.
French marigolds are compact, about 15-30 cm (6-12 in), with smaller single or double flowers, often bicoloured. African marigolds are much taller, about 0.9-1.2 m (3-4 ft), with large pompon flowers.
Sow French marigolds for compact, long-flowering edging, pots and companion planting.
No. Marigold seed germinates whether covered or not; a thin layer of compost or vermiculite keeps it moist. Give seedlings good light as soon as they appear.
On the plains you can sow in three seasons: around mid-September for winter flowers, around June for the rainy season, and in January under protection for summer. In the hills, sow in spring or early summer depending on altitude.
Yes, against root-knot nematodes. Their roots release a compound toxic to these nematodes, so a dense planting dug into the soil can help clean a bed before vegetables.