How to grow Zinnia

Zinnia elegans · common zinnia

A warm-season annual from Mexico, 20 cm to 1.2 m tall by variety, with bright daisy-like heads from summer until frost. Quick and easy from seed, it attracts butterflies and makes an excellent cut flower.

Quick facts

Type	Flower
Family	Asteraceae
Light	Full sun
Soil pH	6.3–6.8
Frost	does not tolerate frost
Soil for sowing	from 20 °C
Germination	6 days
Seedlings ready	29 days
Where it grows	Greenhouse, Open ground, At home

When to plant

Sow for seedlings about 5 weeks before planting out.

Plant out in open ground about a week after your last spring frost, once the soil is warm.

In an unheated greenhouse everything moves about three weeks earlier.

Frost dates · When to plant

Care

Greenhouse

Stage	Watering	Temperature	Feeding
Seedlings	every 2 days	—	—
Growth	every 7 days	—	balanced (NPK), at the start of the stage
Flowering	every 7 days	—	balanced (NPK), 42 days into the stage; balanced (NPK), 91 days into the stage

Open ground

Stage	Watering	Temperature	Feeding
Seedlings	every 2 days	—	—
Growth	every 7 days	—	balanced (NPK), at the start of the stage
Flowering	every 7 days	—	balanced (NPK), 42 days into the stage; balanced (NPK), 91 days into the stage

At home

Stage	Watering	Temperature	Feeding
Seedlings	every 2 days	—	—
Growth	every 2 days	—	balanced (NPK), at the start of the stage
Flowering	every 2 days	—	balanced (NPK), 42 days into the stage; balanced (NPK), 91 days into the stage

Growing notes

Light

Needs full sun all day; in part shade it suffers more from leaf spots and mildew.

Soil

Well-drained loam rich in organic matter; pH 6.3–6.8 is ideal, though it is not fussy about pH.

Care

Start indoors 4–6 weeks before the last frost at 18–24 °C, covering the seed, and disturb the roots as little as possible when planting out; or sow 6 mm deep outdoors after the last frost, once the soil is warm. Space plants 23–30 cm apart for good air flow. Keep the soil consistently moist, watering at the base in the morning so the leaves stay dry. Feed at planting, 6–8 weeks later and once more in late summer. Cut flowers and deadhead often to keep new ones coming. Powdery mildew and leaf spots are the main problems — choose resistant varieties and rotate beds; aphids, spider mites and whiteflies appear in hot, dry weather.

Pests and diseases of Zinnia

Sources

Figures checked against these sources.