Grow Zinnia

Zinnia – a floral praline

With its cheerful colors and sturdy stem, zinnia is a true floral praline. Enjoy the flowers in the garden and bring them inside for summery bouquets. Zinnia is an excellent attraction for butterflies and other pollinators.

Many delicious colors

Zinnia originally comes from Mexico. There it was used as folk medicine, as a plant dye, and in rituals. Linnaeus named the plant zinnia to honor a German botanist named Gottfried Zinn.

Today, zinnia comes in a variety of delicious colors. The height varies from 25 to 80 cm. The smaller varieties are particularly nice in pots and as border plants in flower beds.

Different ways to sow zinnia Pre-cultivate zinnia indoors

Sow zinnia indoors in March-April. Place 1-2 seeds per pot about 3 mm deep. Since the roots are sensitive, we sow zinnia in pots that are at least 7 cm deep. They don’t need to be transplanted until it’s time to move them to their final growing spot. We base the pot with potting soil and have a layer of sowing soil on top. The sowing soil makes it easy for the seed to form roots. The potting soil provides nutrition when the plant has grown big enough to need it.

Zinnia germinates best at 20-22 degrees Celsius. Feel free to use an electric heating mat. Or place the sowing in a warm spot, for example, above a radiator.

Keep the sowing moist but not overly wet, as zinnia can be affected by fungal attacks. When the seedlings have sprouted, they want to stand bright and cool. Water the pots from below. After a few weeks, it’s time for the first nutritional supplement.

Top the zinnia plants when they are about 10 cm tall. They will then branch out nicely and become bushier. Cut just above a pair of leaves. Feel free to put the cut shoot in water. It forms roots and can be planted as an independent plant.

Cold sow / winter sow zinnia

In the spring, many enthusiastic growers lack space on window sills and plant tables. Then winter sowing is very handy. Zinnia is among the summer flowers that can be winter sown outdoors in cultivation vessels, from December to March. The seeds sense when it’s time to germinate and get an early start in the spring.

Direct sow zinnia

In southern Sweden, zinnia can be directly sown outdoors when the risk of frost is over.

Planting out zinnia

Zinnia that has been sown indoors is sensitive to frost. Do not take out the plants until the risk of night frost is over. Harden the zinnias by letting them be outdoors for longer periods over a few days. Protect the plants from sun and wind and bring the pots indoors overnight until they have become accustomed to their new outdoor life.

With its Mexican origin, zinnia is a plant that loves warmth. Choose a sunny spot and it will be happy. Plant in well-fertilized soil with a distance of about 25 cm.

Zinnia may need support, especially if it grows in a windy location.

Easy to care for zinnia

Zinnia is easy to care for. It blooms a lot and long from July onwards. Pot-grown zinnia needs nutrition every three weeks. For zinnia growing in the open ground, it’s enough to get nutrition once during the season when the bloom has started.

Remove wilted flowers over time by pinching off the stem just above a pair of leaves. Then the zinnia will branch out and there will be room for more flowers.

A gem as a cut flower

The more zinnia one picks, the more new flowers appear. It’s a good reason to fill the vases at home. Zinnia, with its fireworks of color, is a real gem as a cut flower. It stays fresh in bouquets for a long time, especially if the water is changed and the stem is cut back a few centimeters now and then. If you want to enjoy the zinnia even longer, you can dry it to preserve it.


Author: Johanna Damm

Fact-checked by Erik Hoekstra

Last updated 2022-10-14

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