How to Grow Zinnias

If you’re looking to add a pop of color to your garden, you may want to consider growing zinnias. Zinnias are fast and easy to grow flowers. These low-maintenance flowers are heat tolerant, drought-tolerant, and even grow well in poor soil. Zinnias are great starters if you haven’t previously grown flowers. Keep reading to learn more about how to grow zinnias.

How to grow zinnias Types of Zinnias

Zinnias are annuals that grow for one season and then produce seeds. The flowerheads are similar to daisies and they make great cut flowers for bouquets to add to vases. They attract butterflies and hummingbirds, making these flowers great companions for a vegetable garden. They’re also great for warmer climates (like Florida) and can take the summer heat.

White and Pink Stripped Zinnia

There are many different kinds of varieties of zinnias with different sizes, colors, and petals. Zinnias can range from being 10 inches tall to 4 feet tall. Taller varieties sometimes do better in clusters or staked with single stem support stakes

Zinnias Growing

Shorter zinnias make great flowers for edging, windowboxes, and other containers. Taller zinnias make great backdrops for flower gardens. One plant can grow up to 12-18 inches wide, with multiple flowers on long stems. The colors range from pale to vibrant, in an assortment of just about every color except blue. These flowers also come in both solids and stripes.

Double Flowered Zinnia

There are three types of zinnia flowerheads when it comes to petal patterns – single, semi-double, and double.

  • Single Flowered: These zinnias have a single row of petals. The center of the flower is visible.
  • Semi-Double Flowered: The flowers in this type have several rows of petals and the center of the flower is visible.
  • Double Flowered: The flowers have several rows of petals, and the center of the flower is visible, it’s hidden in petals.

Zinnia seed packet

With all the variety that zinnias offer, you have a lot to choose from. Check out these zinnia seed varieties for inspiration.

How to Plant Zinnias

Zinnias are easy to plant from seeds. While not impossible, zinnias don’t handle being transplanted well. I personally recommend starting them from seed directly where you plan to grow them. From seed, they will grow very quickly in the right conditions.

Butterfly on Zinnia

Zinnias are annual plants, which means they will only last for one season. Planting Zinnias is not much of a challenge. They require minimum care and maintenance. They are adaptable plants and thrive in warm, dry temperatures. Zinnias don’t handle cold temperatures well, so seeds should be planted after your last frost has passed. See your hardiness zone frost dates.

These flowers enjoy direct sunlight will soil that drains well and with a slightly acidic soil pH. Seeds should be planted 1/4 inch deep, and seeds should be spaced 6-12 inches apart. Seeds will germinate after 4-7 days. 

How to Care for Zinnias

Once seedlings are 3 inches tall they should be thinned to 6-18 inches apart. They take about 60-70 days from seed to flower. If leaves appear to be pale green, you can add some organic fertilizer with a little nitrogen.

Yellow and Red Stripped Zinnia

The primary troublemaker for zinnias is mildew. When the weather is warm and humid, Zinnia plants are usually attacked by mildew. Humid weather is popular here in Florida. To lower your chances of mildew, don’t plant your flowers too closely together to encourage air circulation, and try not to wet the leaves when watering your plants. You’ll want to water the soil while staying away from the leaves. You’ll also want to make sure your soil is well-draining so that your flowers aren’t standing in water.

If you start to see mildew on your zinnia leaves you can slow down the spread by using neem oil or make your own organic solution by adding 1 tablespoon baking soda and 1/2 tablespoon of liquid soap in 1 gallon of water. You can apply the solution with a spray bottle. You should test your solution on a portion of your plant first before spraying the whole plant, and it’s also recommended to avoid spraying during the hottest part of the day.

Aphids also can attack zinnia leaves, causing them to curl and yellow. Neem oil can help with this as well.

After zinnia flowers start to dry you should cut them off (deadhead) to encourage more flowers to form. 

Saving Zinnia Seeds

Dried Zinnia

Saving zinnia seeds for future seasons is an easy task. Once you cut off the dead flowers of your zinnia plants to encourage growth you can use those flower heads to save seeds.

Once you clip off a dried flower head, make sure they are dry. It’s best to allow them to fully dry on your plants, but if it’s going to rain you can clip them and let them continue to dry for 1 to 4 weeks indoors. Mold-causing moisture can ruin seeds. 

Once your flower heads are dry you can pull apart the petals and at the base of the petals, you’ll see the seeds. They look sort of like arrowheads.

Your dried seeds can then be stored in paper envelopes and labeled with the color and date. Envelopes are better to store seeds in versus baggies because they keep your seeds dryer. Keep the seeds in a cool, dry place until it is time to plant next year. 

Do you grow zinnias? Comment below!

How to grow zinnias


  1. Can you reseed the the seed again the same year after it dries

  2. My zinnias come back year after year in N.E. Florida. I understand the original plant is an annual, but those seeds do germinate and its such a joy to see them return!

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