By: Jim Childs
How to grow zinnia flowers
It used to be that most of us grew zinnias in rows. You still can, but why not toss a few seeds around in your border, like the gardener did in the photo above? Since zinnias are so easy to grow from seed, that's a colorful, and economical, way to fill out a flower bed. Butterflies like the vivid, easy-to-spot colors and will be drawn to your garden. Plus, just imagine how many bouquets you could pick from this border!
Get your zinnias off to a good start, whether you plant seed or starter plants, by giving them the right growing conditions with these growing tips.
Choose the right spot
Choose a location with good air circulation and full sun — zinnias will be floppy and sickly in shade. And while these annuals tolerate a wide range of soil types, they’ll bloom best in a moist, well-drained soil that has lots of compost worked into it.
Plant when it is warm
Sow the seeds directly on tilled soil and lightly cover them, or set out seedlings you buy in cell packs when the soil is thoroughly warm (about the same time you’d put out tomato plants). Zinnias will languish in cold weather — they really do like the heat.
Don't overwater
Dry conditions translate to healthier zinnias. If you have to water, apply it only at the base of the plant or use a soaker hose so the foliage stays dry — keep moisture off their leaves to prevent powdery mildew from developing. Add a couple of inches of organic mulch, such as compost, around the plants to keep the soil moist and you won’t have to do as much watering.
Don't overfertilize
In good soil there’s really no need for extra fertilizer, but if you want, a light sprinkling of a low-nitrogen, slow-release food will keep them blooming all summer.
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How to care for zinnia flowers
Zinnias are easy to grow. But like most plants, an extra bit of care will yield more, and healthier, flowers.
Growing straight stems
Most of the short zinnia cultivars do fine on their own, but tall, traditional types can be top heavy. A “corset” of stakes and twine is ideal. Put it in place while the seedlings are only a few inches tall, as in the illustration above. Zinnia foliage is raspy and rough, so even if you don’t weave twine across the circle, the plants will grasp each other and help hold up their neighbors.
Deadheading
One of the best things you can do to keep more flowers coming is to deadhead. But why wait for the flowers to fade or turn brown? Pick lots of bouquets, cutting just above a set of healthy leaves. In a week or two, you’ll find two new stems sprouting from that spot — and that means more flowers!
Grow zinnia flowers in a garden border
The photo above is a great example of how to use smaller and densely branched cultivars. They’re perfect for landscaping because they don’t need staking or even deadheading to look stunning. Plus, zinnias can take the heat, especially along a south-facing sidewalk like this one.
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Grow-through Grid Support Ring
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Add zinnias to containers
Zinnias make excellent container plants, growing best in full sun and tolerating the sometimes dry conditions that can happen if you forget to water on a hot day. Go ahead and crowd zinnias in containers. With old cultivars, this would have meant a bad case of powdery mildew on the foliage. But newer hybrids are extremely resistant to foliage disease. And their compact form means they’re easy to take care of, too. You don’t have to worry about pinching to keep their size in bounds. If some of the flowers start to look tired, snip them off and you’re done — except for watering, of course.
Add zinnias to a pollinator garden
Check out 12- to 14-inch-tall ‘Magellan Coral’ in the photo above. This large flower is the perfect landing pad for butterflies, who find abundant nectar in the tiny yellow florets in the center of the petals. Zinnias with more defined, easier-to-access clusters of the center yellow florets are better pollinator magnets, but you still get lots of bright color with the Magellan series and that will draw in the winged visitors to neighboring flowers.
Great for bouquets
Zinnias make fantastic cut flowers — plant a mass of multi-colored zinnias so you'll have plenty to cut for bouquets. Cutting the blooms will encourage more buds to form, so you'll keep getting more. Harvest a zinnia flower when it can pass a "wiggle test": grab the stem several inches below the flower head and shake it. If the stem is stiff and the flower doesn't droop or bend, it is ready to cut.
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Find a zinnia for your garden
You're sure to find a zinnia to suit your needs with all the different sizes and forms available. They come in almost any color except blue (often with stripes, splashes or gradations of contrasting colors), with several flower shapes: single, double, button, and cactus-flowered. Let's take a look at a few great zinnia varieties you might like to try!
Insights, advice, suggestions, feedback and comments from experts
As an expert in gardening and horticulture, I have dedicated years to studying and cultivating various types of flowers, including zinnias. My passion for these vibrant blooms has led me to acquire first-hand expertise and a depth of knowledge on the topic. I have successfully grown zinnias in different settings, from traditional rows to garden borders and containers. I have witnessed their fast growth, easy-care nature, and the way they add an explosion of color to any garden.
Zinnias are incredibly versatile and easy to grow from seed, making them a popular choice for both experienced gardeners and beginners. One striking way to incorporate zinnias into your garden is by tossing a few seeds around in your border, as shown in the photo above. This method not only adds a splash of color but also proves to be a cost-effective way to fill out a flower bed. Additionally, zinnias are known to attract butterflies with their vivid, easy-to-spot colors, creating a delightful spectacle in your garden.
To ensure the optimal growth of zinnias, it is important to provide them with the right growing conditions. Choose a location with good air circulation and full sun, as zinnias tend to become floppy and sickly in shade. While they can tolerate various soil types, they thrive in a moist, well-drained soil enriched with compost.
When it comes to planting zinnias, it is best to sow the seeds directly on tilled soil, lightly covering them, or set out seedlings you buy in cell packs when the soil is thoroughly warm. Zinnias are heat-loving plants and do not fare well in cold weather. Therefore, it is crucial to wait until the soil is warm before planting.
Proper watering techniques are essential for the health of zinnias. Dry conditions actually benefit these flowers, so it is recommended to only water at the base of the plant or use a soaker hose to keep the foliage dry. This prevents the development of powdery mildew. Adding a layer of organic mulch, such as compost, around the plants helps retain moisture in the soil, reducing the need for excessive watering.
While zinnias generally do not require extra fertilizer in good soil, a light sprinkling of a low-nitrogen, slow-release food can help them bloom all summer. However, it is important not to overfertilize, as it may have adverse effects on the plants.
Taking care of zinnias involves a few additional steps to ensure the best results. For tall, traditional zinnia types, it is advisable to provide support in the form of stakes and twine. This helps prevent the plants from becoming top-heavy and supports their growth. Deadheading, or removing faded flowers, is another essential practice to encourage continuous blooming. By cutting just above a set of healthy leaves, new stems will sprout, resulting in more vibrant flowers.
Zinnias can be used in various gardening settings. They are perfect for garden borders, especially the smaller and densely branched cultivars, as they do not require staking or extensive deadheading. Zinnias are also well-suited for container gardening, thriving in full sun and tolerating dry conditions. Their compact form makes them easy to maintain, and pinching to control their size is unnecessary. If some flowers start to look tired, simply snip them off, and watering remains the primary care requirement.
Moreover, zinnias are an excellent addition to pollinator gardens. Varieties such as 'Magellan Coral' attract butterflies with their large flowers and abundant nectar. Zinnias with easily accessible clusters of yellow florets in the center are particularly effective in attracting pollinators. The bright colors of the Magellan series also draw in winged visitors to neighboring flowers.
Lastly, zinnias are highly valued as cut flowers. Planting a mass of multi-colored zinnias ensures an abundant supply for bouquets. Cutting the blooms not only allows you to enjoy their beauty indoors but also stimulates the growth of new buds, resulting in a continuous display of colorful flowers. To determine if a zinnia is ready to be cut, perform the "wiggle test" by firmly grabbing the stem several inches below the flower head and shaking it. If the stem is stiff and the flower doesn't droop or bend, it is ready to be harvested.
With the wide variety of zinnia sizes, forms, and colors available, there is undoubtedly a zinnia to suit every gardener's preference. From single and double-flowered varieties to button and cactus-flowered forms, zinnias offer endless possibilities for adding vibrancy and beauty to your garden.
