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How to Grow Zinnias: Bold Blooms All Season

Colorful zinnia flowers field blooming in the garden on bokeh blurred background.
Photo Credit
mariokinhed/Shutterstock
Botanical Name
Zinnia elegans
Plant Type
Flowers
Sun Exposure
Full Sun
Soil pH
Neutral to Slightly Alkaline
Slightly Acidic to Neutral
Bloom Time
Summer
Fall
Flower Color
Multicolor
Orange
Pink
Purple
Red
White
Yellow
Special Features
Attracts Butterflies

Planting, Growing, and Caring for Zinnia Flowers

Written By: Catherine Boeckmann Executive Digital Editor and Master Gardener

Looking to add a punch of color to your garden with zero fuss? Say hello to zinnias! These cheerful, daisy-like flowers are summer’s overachievers, blooming in bold colors from midseason to the first hard frost. Butterflies love them, gardeners adore them, and they make spectacular cut flowers. Even better? They’re practically foolproof to grow from seed! Let’s dig into everything you need to know about growing zinnias, your garden’s soon-to-be brightest stars.

About Zinnias - Are Zinnias Perennials?

Zinnias are annuals, so they’ll grow for one season to produce flowers and seeds, but the original plant will not come back in subsequent years. They have bright, solitary, daisy-like flower heads on a single, erect stem, which makes them great for use as a cutting flower or as food for butterflies.

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Types of Zinnias

The most popular zinnia species is Zinnia elegans, which has been bred to produce a great number of unique varieties.

Zinnia flowers come in three main kinds: single, double, or semi-double. The distinction between these forms comes from the number of rows of petals and whether or not the center of the flower is visible:

  • Single-flowered zinnias have a single row of petals and a visible center.
  • Double-flowered zinnias have numerous rows of petals, and their centers are not visible.
  • Semidouble-flowered zinnias are somewhere in-between, with numerous rows of petals but visible centers.

In addition to these forms, zinnia flowers come in a number of shapes, including beehive, button, and cactus. The plants also come in different heights: taller varieties are best for the background of a garden bed, while shorter varieties work well along a border. There’s a zinnia for every garden!

Plant zinnias in an annual or mixed border garden. Smaller zinnias are suitable for edging, windowboxes, or other containers.

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Planting

Where to Plant Zinnias

Choosing a location that gets full sun (6 to 8 hours of sunlight per day) is essential to getting plentiful blooms throughout the season. Additionally, a site that offers good air circulation will help to prevent foliar diseases such as powdery mildew later in the season.

Zinnias are able to adapt to most soil conditions, but the ideal soil will be rich in organic matter and well-draining. Soil pH should ideally be between 5.5 and 7.5. If soil is amended with compost (humus), the flowers will grow more quickly. Learn more about soil amendments and preparing soil for planting.

When to Plant Zinnias

  • It’s recommended that you grow zinnia from seed right in the garden bed, as they do not like to be transplanted. From seed, they will grow very quickly in the right conditions.
    • Note: Zinnias can be started from seed indoors if you prefer—just transplant them while they’re young and do so carefully.
  • Zinnias are sensitive to frost, so do not seed until the last frost has passed in your area. See your local frost dates.
  • Zinnias will grow in a minimum daytime temperature of about 60°F (16°C), though a range of 74°–84°F (23°–28°C) is preferred.
  • Sow a round of seeds every week or so for several weeks to extend the flowering period.

orange and red ZInnia with butterfly

How to Plant Zinnias

  • Space plants 4 to 24 inches apart, depending on variety. (Many common varieties are planted 6 inches apart within the row and 2 feet in between rows.) See the back of the seed packet for variety-specific advice.
  • Sow zinnia seeds only about 1/4 inch deep.
  • Most zinnia varieties grow tall and need staking to prevent their heavy stems from lying on the ground. A few weeks after planting, stake close to the plant stem. Take care not to injure roots.
  • Gardeners who grow many zinnias (especially for cutting) stretch pea netting over young plants between stakes and bamboo canes; the zinnia heads are then supported gently by the almost invisible netting. 

Growing

  • You’ll see zinnia seedlings in only 4 to 7 days for most varieties, though it will be anywhere from several weeks to a couple of months before blooms appear (depending on planting site and climate).
  • When seedlings reach 3 inches tall, thin them so that they’re 6 to 18 inches apart to maximize air circulation. This reduces the chance of powdery mildew developing.
  • Maintain moderate soil moisture and fertilize lightly to maximize growth and blooms.
  • After the zinnias flower, cut off the old flowers (a process called deadheading) to encourage more flowers to form.
  • Zinnias are annuals and will die with the first hard frost of fall. However, if you want them to reseed, let the last flowers of the season mature fully and scatter their seeds.

Types

  • Get a full-size flower on a compact plant with cultivars of the Dreamland Series. Dwarf and compact, these zinnias have fully double flower heads, up to 4 inches across in a wide color range; stems are 8–12 inches tall.
  • The Thumbelina Series cultivars are dwarf and spreading, with single or semidouble, weather-resistant flower heads in many colors. Their petals are 1-1/4 inch across and stems grow up to 6 inches long.
  • The State Fair Series are one of the biggest and tallest of them all, with large, double flower heads that are 3 inches across. Stems grow to 30 inches tall.

Harvesting

  • Zinnias generally take 60 to 70 days from seed to flower (though it depends on conditions and variety). They work great in a flower bouquet!

Saving Zinnia Seeds

To save zinnia seeds for replanting, simply collect a few blossoms that are at least halfway brown and let them dry in a paper bag until the seeds shatter. 

  • Find the dark, pointed seeds at the bases of outer petals, with more along the center of the flower.
  • Dry on a paper towel until hard and almost crisp.
  • Store in a paper bag in a dark, dry location until you plant again in the spring.

Zinnia bouquet on a kitchen table

Gardening Products

Pests/Diseases

  • Bacterial and fungal spots, powdery mildew, and bacterial wilt may affect zinnias. Minimize wetting of foliage and space plants properly to avoid disease.
  • Caterpillars, mealybugs, and spider mites also cause problems. Some leaf damage is not an issue, so avoid spraying unless there’s an actual infestation.
  • Luckily, zinnias are deer-resistant, so they might help keep nearby flowers from being eaten.

Wit and Wisdom

  • The small, narrow-leaf zinnias work well in hanging baskets and make for nice dried flowers, too.
  • It’s said that zinnias symbolize thoughts of absent friends. Learn about more flower meanings here.

Flowers
About The Author
Catherine Boeckmann

Catherine Boeckmann

Executive Digital Editor and Master Gardener

Catherine Boeckmann is the Executive Digital Editor of Almanac.com, the website companion of The Old Farmer's Almanac. She covers gardening, plants, pest control, soil composition, seasonal and moon c...
Read More from Catherine Boeckmann

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Comments

<span>Pat Bolster</span> Fri, 10/18/2013 - 16:19
Love this site!! Very informative. I have a butterfly garden here in the east side of Phoenix metro and decided in early Spring to try zinnia seeds for the first time. Holy mackeral!! I hit the motherlode. The seeds (all of them it seems!) germinated overnight practically and very quickly sprouted up, grew about four feet tall blooming all the while. Actually, it was a bit frightening as they kept growing UP! LOL. So they stood tall like a forest and just bloomed and bloomed and bloomed (no kidding!). One of the wild duststorms whirled through and the zinnias bowed to it, and stayed that way, but kept blooming. Now more branches have sprouted vertically from the horizontal stalks and are again blooming. What a bonanza. The butterflies, the bees, the hummingbirds,the wasps, even some strange looking critters with dragonfly like wings have enjoyed the zinnias. It is sheer joy to have such success and as it is only mid October, I'm hoping the blooming will last a few more months. It's still in the mid 80's daytime, very sunny, blue sky! Thanks for your website and Good luck with your zinnias everyone!
<span>Kathy Newhouse</span> Sun, 09/08/2013 - 16:49
Where can I buy zinnia hybrid seeds?
<span>Robyn Kurtz</span> Wed, 09/04/2013 - 13:02
Next summer my son is getting married on July 19th. The bride is excited about having zinnias as table decorations. I have plenty of garden space and I am happy to try and grow some flowers for her. If I don't do a good enough job for the wedding decorations I will simply enjoy the color and use them for my home when guests arrive. I have studied your tips and I will follow the directions on the seed packets. Do you have any names of zinnias that make better cut flowers for table decorations. Please give me information on proper cutting, storage and making sure they are bug free for decorations. Thanks- Robyn
<a title="View user profile." href="/author/editors">The Editors</a> Sat, 09/07/2013 - 15:18

Zinnias are perfect cutting flowers! We have a huge cutting garden of zinnias right down the road here in New Hampshire and go all the time. "Pumila" or "Cut And Come Again" is an old favorite for cutting and offers an almost continuous bloom for several months which may make it more likely that you hit her wedding date. They have a lovely rounded blossom form and many stems for cutting. Just back out the "days to maturity" and stagger your plantings to have a chance at hitting her date. We're glad to hear you're realistic about it all!

 <span>Oscar Rodas</span> Tue, 08/27/2013 - 02:17
I have learned a lot by reading the info. on this site. I have just started working with Zinnias and so far so good. I am expecting the first blooms in two weeks (Is the end of August and I am in the high deserts of Southern California).
<a title="View user profile." href="/author/editors">The Editors</a> Tue, 08/27/2013 - 15:44

Many thanks, Oscar. Wishing you colorful, plentiful zinnias!

 <span>Three Dogs Mama</span> Fri, 08/23/2013 - 23:13
I did everything wrong in my zinnia bed. Now they are really tall and blooming but the leaves are all "rusted" and wilted because I watered them incorrectly. I think they were a little too crowded, too, but I had planted them in a huge circle and somehow they all ended up washed to one side of the tree. Also it is so humid here. I want to cut them back for better fall blooming, but I am wondering if they will indeed "come again" when all the leaves are dead at the bottoms.
<span>Mike Mcknelly</span> Fri, 08/23/2013 - 15:59
For winter do I cut back to ground level?
<a title="View user profile." href="/author/editors">The Editors</a> Mon, 08/26/2013 - 11:27

Zinnias are annuals. Remove the plants at the end of the season and replant next spring.