May 12, 2021

How to grow productive Zinnia flowers from seed in your backyard + our most loved varieties

Gardeners across the world have fallen in love with Zinnia flowers, and the good news is they are really easy to grow from seed!

Zinnias are frost sensitive, so wait until the last frost has passed to plant. Zinnias don't like being transplanted, so if you live in a warmer climate sow Zinnia seeds direct where they will grow, germination should occur in 3-7 days depending on soil temperature.
If you live in a cooler climate, you will need to start them in a greenhouse environment. Using peat pots (biodegradable pots) that can then be directly sown into the ground will help prevent transplant shock. Transplant when they are young and if transplanting from regular pots try not to disturb the root system.
Do not allow plants to become root bound and avoid disturbing roots; transplant shock or other stress events may cause double-flowering varieties to produce single blooms for a period following stress.
Pinch out your zinnia seedlings when the are 30cm tall (3 true sets of leaves). Pinching out means taking the top 10cm off your seedling. This will encourage stronger, taller stems and more flowers!
Zinnias are heat lovers, so plant in full sun with good air circulation, this will prevent them from getting powdery mildew.
Space between 15 - 30cm apart (depending on the variety) and rows 30 - 45cm apart.
Zinnias may require support, so the use of flower netting staked 30cm above the ground will give them the support they need.
When established try not to water the leaves, water the base of the plant. They don't like to be water logged.
Zinnias are annuals, when flowering, deadheading any flowers that have died will encourage more to grow!
Harvest your zinnia blooms when they are in full bloom and the stems are stiff.

Types of Zinnias:

There are 3 main types of Zinnia flowers, double, semidouble and single.

Double - Multiple rows of petals and no visible centre

Semi Double - Multiple rows of petals with a visible centre

Single - A single row of petals with a visible centre

Our most loved varieties:

Queen Series including the gorgeous Queen Lime with Blush, Queen Red with Lime, Queen Orange with Lime and Salmon Rose Queen. The Zinnia Queen series are mostly double and semidouble blooms with a small percentage of singles.

Zinderella Peach fully-double, semidouble, and approximately 20% single flowers. Unique salmon / peach colour with cream-to-rose petals and a distinct dark eye.

Benary's Giant Coral is a cultivar is known as the dahlia-flowered zinnias, they have large double dahlia like flowers in salmon rose to coral.

Frequently asked questions about growing zinnia flowers:

How can I prevent zinnia mould + mildew?

Make sure there is plenty of space between each plant, this will enable plenty of airflow which will reduce the chance of mildew and fungal diseases. Water at the root of the plant early in the morning and avoid over watering. Keep dead leaves well pruned and make sure the zinnias are in a light sunny spot in the garden.

Why are my zinnia seedling leggy?

If your zinnia seedlings are legging this means they are lacking sunlight.

They have become legging as they are looking for light. To stop them from being leggy put the zinnia seedlings in a sunny spot where there is plenty of sunlight.

How can I get tall stems and lots of zinnia flowers?

Pinching out the tip of the zinnia seedlings when they are 30cm tall will encourage stronger stems and loads more flowers.

Why are my zinnias not flowering?

Zinnia love sun and warmth! Making sure they are sown or planted in a full sun position will help encourage growth and flowers.

When to sow zinnia in Australia?

Spring to mid summer in most areas and can also be planted over winter in warmer areas of Australia.