Planting, Growing, and Caring for Zinnia Flowers
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Planting
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.
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.
- 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.
Catherine Boeckmann
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I have been growing Zinnias for almost 20 years . Love them. Over the last few years, however, I am no longer getting the big, snowball type of flowers. They are more...not sure what word to use to describe them but they are no longer the huge, multi-layered round "snowballs". Same yard for past 13 years. Any idea? I get my seeds from the same place every year and the same kind (Parks Picks form Park seed). Thanks!
Our guess would be that the zinnias have used up most of the soil’s nutrients in that spot. Before you seed next year, mix one or two inches of compost into the soil to add nutrients and loosen the soil a bit, which the zinnias should also appreciate. For this season, try adding some balanced fertilizer and see if that improves blooms.
My roommate accidentally mistook my zinnia's for basil, and removed the beginning buds. Will they persevere and flower anyway?
Most zinnias respond very well to the removal of old flower buds (deadheading), which can encourage them to bloom again. Now, in your case, the deadheading was a bit premature, but it will probably have the same effect. All you can really do is wait and see!
The temperatures in summers is too high as the maximum temperature recorded in Rajasthan,India is about 122 degree F in summers. So can i plant the Zinnias i August and still get good flowers. There is no frost here due to extremely high temperatures
Yes it can our temperature is about 90 to 125 Fahrenheit it's blooming flowers all day water it twice or thrice a week
Zinnias are far from deer proof; I've had firsthand experience for more than 25 years. Matter of fact, almost no plant should be labeled as deer-proof. I've had deer munch/destroy daffodils, which are known to be toxic. And, yes, deer were the culprits; the proof was in the hoof prints.
We agree. There is no such thing as deer-proof. That said, some plants are deer candy and preferred by deer to other plants. Zinnia are considered deer-resistant. Of course, in bad weather, deer will eat anything, including holly!
We run a fall corn maze and are looking into opening up for a spring flower picking event. We are in Zone 8B in southeast Alabama and have had an unseasonably warm winter so far (maybe 3 days below freezing, most days 70+ degrees). I would like to plant zinnias, sunflowers, and wildflowers so that we have blooms for flower cutting the last week of April and first week or so of May/Mother's Day (actually April 22 but I think that may be pushing a little too much). We have underground irrigation if needed. When would you advise planting the zinnias to potentially best hit this window? Is it even possible?
The best idea might be to start seeds indoors to get a jump on bloom time. But since zinnias don’t like being transplanted, sow them in peat pots that can be directly transplanted into the garden. Zinnias generally take 60 to 70 days from seed to flower so sow accordingly.
