Learn how to grow low-maintenance zinnias and add a long-lasting pop of color to your garden during even the hottest months of the year. Butterflies, bees, hummingbirds, and other pollinators are drawn to these vibrant flowers. Zinnias make excellent cut flowers, and come in varied sizes, colors, and textures. 

How to grow Zinnias - 5 Tips for Growing Zinnias

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5 Tips for How to Grow Zinnias

How to grow Zinnias - 5 Tips for Growing Zinnias

1. Start zinnia seeds indoors or in the garden

If you have purchased zinnias from a local nursery and been disappointed with the results, try planting them from seed instead. I’ve had the most success starting zinnias indoors in seed trays just a few weeks before the last frost date. I use these trays from Amazon. Then I transplant them into the garden when they are a few inches tall. You can also plant seeds directly in the garden when the soil has warmed to around 75℉.

In the low desert of Arizona

  • Start zinnia seeds indoors in February for an early start.
  • Plant zinnias from seed or transplant March through June.
  • Zinnias bloom from April to November.
How to grow Zinnias - 5 Tips for Growing Zinnias

To start zinnias from seed (indoors or outside), poke the pointy end of the seed into the soil and then cover it lightly with soil. Space plants 6” to 18” apart depending on the variety to maximize air circulation and reduce powdery mildew.

How to grow Zinnias - 5 Tips for Growing Zinnias

2. Plant zinnias in the right location

  • Plant zinnias in rich soil amended with compost and organic fertilizer. Zinnias don’t need supplemental fertilizer throughout the season.
  • Give zinnias plenty of sun. Zinnias grown in the shade are often leggy and susceptible to mildew. 
  • Zinnias do not like getting their leaves wet. Use drip irrigation rather than spraying them overhead. Water can burn leaves and cause problems with powdery mildew.
  • I love planting zinnias along the edges or borders of garden beds where they add beauty and attract pollinators.
How to grow Zinnias - 5 Tips for Growing Zinnias

3. Prune zinnias back when young for more blooms

This tip for how to grow zinnias will make the biggest difference in the number of blooms. When the young zinnia plant is 6-8 inches tall, cut the central stem just above 2-3 side shoots. This early pruning encourages multiple stems rather than one.

How to grow Zinnias - 5 Tips for Growing Zinnias
How to grow Zinnias - 5 Tips for Growing Zinnias

4. Harvest flowers often to encourage more blooms

Zinnias are an excellent cut flower and last up to 10 days in a vase. Zinnia blooms don’t continue to open once cut; harvest flowers when all the petals are open. Cut the flower at the end of the stem when harvesting.

How to grow Zinnias - 5 Tips for Growing Zinnias

5. Save zinnia seeds each season

At the end of the season, leave the blooms on the largest, prettiest flowers. Let the flower head dry completely on the plant. Seeds are ready when the flower head is dry and brittle. The petals will dry and fall away. The seeds are the large plump center of the flower headRead this blog post to learn more about how to save seeds

Harvest the seeds to plant in your garden next season and to share with friends. Teach your friends how to grow zinnias too. 

How to grow Zinnias - 5 Tips for Growing Zinnias

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How to grow Zinnias - 5 Tips for Growing Zinnias
How to grow Zinnias - 5 Tips for Growing Zinnias
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3 comments on “How to grow Zinnias – 5 Tips for Growing Zinnias”

  1. Hi! I planted Zinnia from seed at the end of May, and so far I have 6″ skinny stems with only a few leaves. The bottom leaves keep turning brown and falling off. I’m watering daily at sunrise and I have them mulched with a shade cloth, but is the AZ sun still too hot for them?

    • Hi. That is frustrating. What is your soil like? Mine are in full sun with about 15 inches of good soil. Be sure not to get water on the leaves. Also cut them back when they are a few inches tall to encourage branching stems.

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