How to grow Calendula

Calendula officinalis · pot marigold

Hardy annual with orange or yellow daisy-like flowers 5–8 cm across. It blooms over a long season, almost without a break until the first heavy frost, prefers cool weather and may pause in a long hot spell, recovering when it cools down.

Quick facts

Type	Flower
Family	Asteraceae
Light	Full sun
Soil pH	6–7
Frost	tolerates light frost
Soil for sowing	from 15 °C
Germination	10 days
Seedlings ready	35 days
Where it grows	Greenhouse, Open ground, At home

When to plant

Sow for seedlings about 6 weeks before planting out.

It tolerates light frost: plant out in open ground about three weeks before your last spring frost.

In an unheated greenhouse everything moves about three weeks earlier.

Frost dates · When to plant

Care

Greenhouse

Stage	Watering	Temperature	Feeding
Seedlings	every 3 days	—	—
Growth	every 4 days	—	balanced (NPK), at the start of the stage
Flowering	every 4 days	—	balanced (NPK), 30 days into the stage; balanced (NPK), 60 days into the stage; balanced (NPK), 90 days into the stage

Open ground

Stage	Watering	Temperature	Feeding
Seedlings	every 3 days	—	—
Growth	every 7 days	—	balanced (NPK), at the start of the stage
Flowering	every 7 days	—	balanced (NPK), 30 days into the stage; balanced (NPK), 60 days into the stage; balanced (NPK), 90 days into the stage

At home

Stage	Watering	Temperature	Feeding
Seedlings	every 3 days	—	—
Growth	every 3 days	—	balanced (NPK), at the start of the stage
Flowering	every 3 days	—	balanced (NPK), 30 days into the stage; balanced (NPK), 60 days into the stage; balanced (NPK), 90 days into the stage

Growing notes

Light

Full sun, at least 6 hours of direct light a day. A little shade helps in hot summers, but in too much shade the plants grow leggy.

Soil

Any well-drained, moderately fertile soil with a pH of 6–7. Plants flower best when they are not heavily fed.

Care

Sow 0.5–1 cm deep around the last frost date, or start indoors 4–8 weeks earlier; cover the seed, as light inhibits germination. Seedlings appear in 1–2 weeks; thin them to 20–30 cm apart and pinch young plants for bushier growth. In mid-summer give about 25–38 mm of water a week without waterlogging, and a complete fertiliser about once a month. Deadhead regularly for more flowers, leaving a few heads if you want self-sown seedlings. Plants survive frost down to about −4 °C. Watch for aphids, whitefly and powdery mildew.

Pests and diseases of Calendula

Sources

Figures checked against these sources.