Are zinnias easy to grow

How to Plant and Grow Zinnias

From watering tips to when to deadhead, we asked two gardening experts to share their advice.

Caroline Biggs, Freelance Writer portrait

By Caroline Biggs October 08, 2020

If you're a fan of colorful, low-maintenance flowers, then you shoulder consider planting zinnias in your garden. "Zinnias are universal symbols of summertime that bloom from mid-summer until the first frost, in crisp, vibrant colors such as pink, red, orange, yellow, green, and white," says Venelin Dimitrov of Burpee. "The flowers bloom in a range of shapes, including quilled, dahlia-type, single, semi-double, and double flowers. Plus, they are excellent flowers for new gardeners and children to grow, as the seeds are large and easy to handle, and the flowers often attract many species of butterflies."

zinnias in a garden

Credit: Getty / Chuanchai Pundej / EyeEm

Along with being beautiful and easy to grow, zinnias are also heat- and drought-tolerant. "They are great for hot summer weather and gardeners in warmer climates," explains Dr. Gladys Mbofung-Curtis, a garden expert at Garden Safe. "Zinnias are one of the easiest flowers to grow because seeds require only basic garden preparation to sprout and the plants flower in just a few weeks; they can flourish with very little fertilizer and still produce flowers."

Plant zinnias in full sun.

Zinnias thrive in full sunlight and should be planted at the beginning of the warm weather season. "They are short-day plants that flower when the day length is less than 11 hours, therefore they are perfect for early spring planting when the nights are longer," Mbofung-Curtis explains. "Zinnias grow and flourish well in full sunlight in cooler climates, but in warmer climates, occasional afternoon shade may help relieve the plants from the excessive heat."

Seed zinnias in moist soil.

In warm climates, zinnias should be seeded directly into the soil after any frost has passed, says Mbofung-Curtis; in cooler climates, seeds can be started indoors in germination trays. "Whether seeding directly in beds or germination trays, zinnia seeds should be sown to a depth of a quarter of an inch into deep, loamy soil," she says. "The distance between seeds or seedlings in the beds should be about six inches apart for good airflow and rows should be spaced 12 inches apart."

Water carefully.

Even though zinnias can tolerate short periods of drought, Mbofung-Curtis says they'll grow best in moist soil. "Water plants about three times a week so that the soil stays moist to about six to eight inches deep," she advises. "Overwatering and continuous wet conditions can take a great toll, since high humidity can lead to development of powdery mildew, leaf spots, and rot, so water at the base of the plants." For potted plants, she recommends only watering them when the soil feels dry. "Avoid splashing the leaves as this may splatter spores of the fungus from the ground to the leaves."

Mulch makes a difference.

While zinnias can grow well in average soils, Mbofung-Curtis says they'll perform better with the help of compost, fertilizer, or mulch. "Once zinnias are established, mulching with a two-inch layer of straw or bark will help preserve soil moisture and prevent weed growth. In addition, a light fertilizer may be applied at the seedling stage. At flowering, side dressing with an organic 5-5-5 fertilizer will produce numerous and bigger blossoms. Zinnia seeds can also be sowed directly into one to two inches of organic mulch that will provide nutrients throughout the season as the mulch breaks down to form compost."

Prune frequently.

A little pruning can go a long way when growing zinnias in your garden. "When zinnias have grown to several inches, prune frequently to encourage more branches for flower head growth," Mbofung-Curtis says. "Rather than allowing flowers to be spent on the plants before deadheading, cut the mature flowers for use in bouquets to encourage blossoming throughout the season. Otherwise, just pinch spent blossoms off. However you maintain them, your zinnias will continue blooming to produce more and more flowers. "

How to grow Zinnias - 5 Tips for Growing Zinnias


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. 

Disclaimer: This post may contain affiliate links. See my disclosure policy for more information.

5 Tips for How to Grow 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 use zinnia seeds from Botanical Interests.

I’ve had the most success starting zinnias indoors in seed trays just a few weeks before the last frost date. I use these seed starting trays from Bootstrap Farmer. I transplant them into the garden when they are a few inches tall.

In the low desert of Arizona

Start seeds indoors:

February – May

Plant seeds or transplants outside:

March – June

Zinnias bloom from April to November.

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.

2. Plant zinnias in the right location

3. Cut 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 18 inches tall, cut the central stem just above 2-3 side shoots. This early pruning encourages multiple stems rather than one.

Flowers to Plant Outside & Seeds to Start Indoors Each Month in the Low Desert of Arizona.
• PLANTING GUIDE: Each month lists annual flowers and bulbs to plant outside & seeds to start indoors.
• BLOOMING GUIDE: Photos show what may be in bloom that month.

Learn More

4. Harvest flowers often to encourage more blooms

Zinnia blooms don’t continue to open once cut. Harvest flowers when the petals are open and the stem has stiffened. Zinnias are an excellent cut flower and last up to 10 days in a vase with a floral preservative.

If you are not harvesting the blooms for cut flowers, keep the spent flowers deadheaded to encourage the plant to produce new blooms (not seeds).

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 head. Read 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. 

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Growing zinnia from seeds. How to get lush bushes

Unique flower arrangements with zinnias are quite an exciting sight. Smooth rows of amazing colors of unbending zinnia give the impression of a military bearing. Perhaps that is why the second name of the flower is majors. Marked very accurately. Just tough tin soldiers. Only very bright cheerful and friendly.

tracy ducasse /

And not only friendly, but also quite unpretentious in planting and care. nine0003

To grow a worthy flower, you need to know the individual preferences of zinnia and try to stick to them.

So, for example, when planting it is necessary to take into account that this plant loves heat and light. Accordingly, will not suit her, place is somewhere in the shade. Zinnia will not survive even short-term drops in temperature to negative values. This means that it should be planted only when it is known for certain that the frost period has ended.

Zinnia loves watering , but will never put up with waterlogging of the soil. However, as with weak moisture in the root layer. Low moisture reserves in the soil are immediately reflected in flowering - the flowers become smaller and begin to dry out a little bit. Exit? Only uniform and regular watering (without overflow) and zinnia will show itself in full glory. In continuation of the topic of watering, I note that in order to avoid stagnant water, the soil should be provided with good drainage when planting a plant. In general, the soil should be loose and fertile. nine0003

It is very good if the soil is filled with organic and mineral fertilizers already in autumn.

Elena Sukhanova / Personal archive

Planting zinnia. You can sow zinnia seeds directly into open ground or grow seedlings first. The second method will allow you to get earlier flowering. Both the first and second cases are simple and do not create problems. Zinnia seeds are quite large, it is pleasant to deal with them.

Before planting, it is necessary to help the seeds: treat them with a growth stimulator, germinate and select with good germination. nine0003

If you prefer seedling method, it is better to choose separate containers, and even better - peat cups. Zinnia does not like transplants, so by choosing them, you will make the moment of planting in open ground the least traumatic.

Zinnia is a fast growing flower so don't try to plant seedlings before April. With early sowing, the condition of the seedlings worsens, it stretches and becomes thinner.

Seeds are sown to a depth of 1 cm. It is not necessary to cover and create a greenhouse effect, they will germinate in a week anyway. Seedlings will need watering, a few top dressings, and hardening before planting in the ground. To form a beautiful bush, pinch the top. When the cold leaves, the seedlings can be sent to the flower bed. nine0003

Elena Sukhanova / Personal archive

Zinnia is planted in a flower bed at a distance of 30-35 cm from each other, the same distance is given between rows. Planting can be done in different ways. In a row, in a hole, as you like. If you thicken the landing, you can always correct the situation by thinning.

When planting seeds in open ground, it is, of course, difficult to indicate the exact dates. You just need to remember that the seeds germinate for about a week and it is very important that the frost period is over by this time. Otherwise, just cover the landing with a covering material. nine0003

In open ground. Of course, most often preference is given to planting seeds immediately in open ground. Planting seedlings, for example, at the end of May, the flowering of zinnia will begin at the end of June, and having planted seeds at the same time, we will see flowering zinnia at the end of July.

Care of growing zinnia involves moderate watering (no overflow), weed removal and loosening.

If you like lush bushy zinnias, pinch the center of the stem. If you prefer tall and slender plants, this technique does not apply. As for top dressing, if zinnia feels great in a flower bed, it does not need to be fed. Only in cases of retardation in growth and development are complex mineral supplements indicated. nine0003

Suzie's Farm /

In favor of planting zinnia in your garden is the fact that modern varieties offer a rich range of colors. The size of the inflorescences and the variety of heights are impressive: from 20 cm to 100 cm, i.e. for every taste. Zinnia blooms for more than a month. She proved herself excellently in the cut. A bouquet, with proper care, stands in a vase for a week or more.

In my opinion, with such exceptional qualities, it is worth making a choice in favor of the majors. Do you agree? nine0003

Related information

Related discussions

How to grow zinnias from seeds.

Sowing for seedlings and in open ground, care. Photo - Botanichka

Extreme sensitivity to low temperatures makes zinnias summer-like, which are usually grown through seedlings. But on the other hand, in sowing, and growing young zinnias, there is nothing complicated. They are hardy, low maintenance and low maintenance plants that are easy to grow from seed. And if you also collect your own seeds, you will get one of the most "economical" summers in your garden collection. Bright baskets of inflorescences, without which it is difficult to imagine summer flower beds, flower beds and mixborders, color the garden with a special cheerful canvas. nine0003 How to grow zinnias from seeds

Zinnias - botanical features of the plant

Zinnias are one of the most popular garden annuals. They have become so familiar to both urban landscaping and private gardens that they are included in the list of classic seasonal plants. Bright colors and greenery, and inflorescences are the main advantage of zinnia. Although everyone who grew these annuals fell in love with them for their endurance and unpretentiousness.

These are compact herbaceous annuals (perennial species are not hardy and are not used in landscape design) with strong, stiff, ribbed shoots and ovate sessile leaves. Whole, arranged oppositely, in pairs or whorls, the leaves show off a light grassy-emerald color and a matte, pleasant to the touch surface. nine0003

Inflorescence heads are typical in structure, but easily recognizable by appearance. A multi-row imbricate wrapper surrounds flat baskets of reed, rather wide flowers, surrounding a convex core of tubular flowers. Each flower is able not to lose its decorative effect for about a month, and sometimes up to 35 days.

Zinnia cannot boast of a variety of options and methods of reproduction. They are grown only from seeds. In regions with mild winters, the sowing of the plant can be carried out immediately in the soil, with the protection of crops with shelter and careful care for young shoots. nine0003

Zinnias are also sown in open ground in the middle lane, but such plants begin to bloom only towards the end of summer, often not having time to show off in full force. The most popular method of propagation of zinnias remains the cultivation of seedlings.

Zinnias flower about 10 weeks after sowing. These are fairly strict annuals in this parameter, in which it is easy to control the start and timing of flowering.

In regions with mild winters, zinnias can be sown directly into the soil. © Carl Cabrera

Self-collection of seeds and their selection for planting

Zinnias are most often grown by cutting off withering heads to prolong their flowering period. Leaving the inflorescences, you can wait for the maturation of oval-wedge-shaped, flattened, special seeds. Full-fledged zinnia seeds can only be obtained from healthy, well-developed plants that have not overgrown at the seedling stage and are not transplanted too early into the soil. It is worth choosing the strongest bushes, leaving baskets for collecting seeds on the shoots of the first order. nine0003

On average, the seeds ripen 60-65 days after flowering. Achenes can be tied up to protect against spillage, but zinnias are usually not prone to unexpected cracking and it is easy enough to collect achenes from them if the timing is observed.

Freshly harvested seeds are dried for several days in the dark at normal temperatures and sorted. Due to cross-pollination, usually even when collecting boxes of the variety you like, the seeds will have a wide variation in characteristics.

Zinnia seeds are immediately divided into groups, sorted by shape and size. Simple inflorescences produce brown, corymbose and flat seeds; semi-double or terry - elongated dark and narrowed at the base, but large-flowered terry zinnias can be obtained by selecting grayish seeds with an even more elongated shape and subulate outgrowth. Store zinnia seeds with protection from light, in "breathing" paper bags or packages in the cold, but without negative temperatures. nine0003

Zinnia seeds have excellent germination potential and can be used for at least two years, and if stored refrigerated up to 4 years after harvest. Checking for germination and culling after soaking allows you to get friendly shoots. Seed germination in zinnia is high, up to 95% in the second year.

Choosing zinnia seeds is no problem. It is an affordable plant in proven varieties and mixes, often found in seed mixes for balconies or flower beds. Since the seeds remain viable for a long time, it is enough to check the completeness of the information, the characteristics of the variety and choose trusted suppliers. nine0003

Read also our material Zinnias in the garden - description, types, use.

Zinnias are suitable for all-purpose potting soil, flower or vegetable. © alecweinstein

Soil and containers for sowing

Zinnias should preferably be sown in individual containers that do not require transplanting - peat pots or peat cassettes. They develop quickly and powerfully, form strong roots, require considerable space and bloom faster if the seedlings are not disturbed. But they are not afraid of transplantation. nine0003

If it is not possible to sow in peat containers, sow in boxes and general containers, selecting them so that there is no need for a dive or it would be possible to carry out a dive without serious injury to the roots. The standard depth of containers is 10 cm. When sowing in ordinary flat containers, you need to prepare deep individual glasses at once, making sure that the earth ball does not collapse when planting seedlings and the plants do not outgrow.

Zinnias are suitable for all-purpose potting soil, flower or vegetable. The main attention should be paid to a light, loose texture and neutral pH values. It is not necessary to disinfect the soil before sowing for zinnias. nine0003

Sowing seeds

The second decade of April is considered the best time for sowing zinnia seeds. Early sowing is undesirable, because seedlings grow very quickly and stretch significantly, outgrow even when sown at the end of March. A later sowing accordingly delays flowering and makes caring for plants after transplantation more difficult.

If you plan to use zinnias in pots, want to decorate balcony and window boxes, flower beds with them, then you can sow them immediately in a permanent container, then thin out the seedlings. It is better to postpone sowing for balconies and potted gardens until the first half of May, for stationary flower girls - until mid-May. nine0003

Zinnia seeds require pretreatment. A simple soaking for several hours is necessary not only to select high-quality germinating seeds, but also to reduce the waiting period for seedlings and the uniformity of their germination. Usually, zinnias are scattered on a damp cloth or napkin and left in a warm, bright place. The use of stimulants is not prohibited, but zinnias sprout together anyway.

Sowing is easy:

  1. The containers are half filled with soil, slightly compacting the substrate. nine0126
  2. Fill the containers with soil, leaving 2.5-3.5 cm to the top (this will allow you to add the substrate later, deepening the seedlings). The soil is leveled and moistened. If you are not going to add the substrate again, then make small holes in the soil about 1 cm deep.
  3. 2-3 seeds are laid out in each pot, gently moisten them and fall asleep or cover with a substrate. The planting depth for zinnia is 1 cm. When sown in common containers, the seeds are laid out at a distance of 4-5 cm between groups or individual seeds. nine0126
  4. From above, the substrate is moistened from the sprayer.

It is not necessary to cover the containers with film or glass, but if possible, moisture stabilization for seedlings does not fit. Shelter from the containers must be removed immediately, as soon as the first shoots appear.

Zinnia seedlings love consistently warm temperatures. © Creative Keri

Seed germination conditions

Zinnias usually germinate very quickly. The wait lasts only a few days, provided that freshly harvested (last season) seeds are used, and up to 10 days for seeds that are stored for 1-2 seasons. nine0003

Zinnias love consistently warm temperatures. The optimal indicators for germination are from 22 to 26 degrees. Bright lighting is needed only when shoots appear, but since this plant germinates very quickly, in order not to miss the moment of sprouts, it is better to immediately place the containers in a well-lit place.

Growing plants

For young seedlings, it is important to maintain bright, diffused light, avoiding overstretching of seedlings. If the weather is very cloudy, it is better to provide additional lighting in advance, but stretching can be handled in another way. You can not be afraid to deepen the stretched seedlings of zinnia, gently filling the soil without tamping down to the cotyledon sprouts. Plants actively form adventitious roots and, without waterlogging, are not prone to rotting of the trunk. nine0003

Water the seedlings carefully, but do not let the soil dry out. Waterlogging is just as dangerous for zinnias as it is for any other flyers.

Seedling diving and caring for young zinnias

It is undesirable to carry out diving for zinnias, because the plants are actively growing and they do not need extra pauses. When planting in individual containers, you can leave all 2-3 sprouted sprouts, but if you want to get single bushes, leave the strongest sprouted plant.

If sowing was nevertheless carried out in common containers, then diving is carried out when 1-2 true leaves open on the plant, very carefully, keeping the soil around the young plants. When diving, the main root can be pinched, but any injury will slow down the growth of zinnia. When diving, plants are buried to the cotyledons, if it has not been carried out, and this measure has not been taken earlier. At the stage of the second leaf, the soil is filled up to the cotyledons to improve the volume of the root system. nine0003

It is quite easy to grow zinnia seedlings:

For zinnias, you need to carefully choose both the place and the time of planting seedlings. © kellydna

Hardening off seedlings

Hardening off zinnia seedlings starts very late, when the average nighttime temperatures rise above 10 degrees. Temperatures must be closely monitored. Usually, for the middle band of zinnia, it is recommended to harden only from the third decade of May. The plant is accustomed to fresh air and low temperatures gradually, leaving it in the fresh air only during the day in the first week and increasing the time spent by the time of planting. nine0003

Planting zinnias outdoors

For zinnias, both the place and the time of planting seedlings must be carefully chosen. The thermophilicity of plants requires waiting not until the end of May, but until the end of the first or beginning of the second decade of June, when the threat of return frosts completely disappears.

Sunny, warm, sheltered areas, light fertile soil with a neutral reaction - the main conditions for the abundant flowering of zinnia. It is better to prepare a place for planting seedlings in the fall or a few months before planting, applying organic fertilizers to increase nutritional value and improve soil texture. Complete mineral fertilizers in a standard dosage of 50-60 g per square meter are applied immediately before planting the plant on depleted soil. nine0003

Zinnias are planted in individual holes, in large continuous plantings - in order. The optimal distance when planting seedlings: from 20 cm - for low-growing varieties, up to 30-35 cm - for high varieties (between the bushes and to neighboring plants).

The main secret of success is the complete preservation of the earthy clod and minimal contact with the roots. If the seedlings were grown in peat pots, they are simply installed in the pits, filling the free space with the substrate. If zinnias were grown in individual pots or glasses, and even more so in boxes, seedlings are removed with as much as possible a whole earthen clod. nine0003

After planting, zinnias must be looked after. Watering in drought until the plants are fully adapted will allow the bushes to quickly start growing and please with abundant greenery. If there are very hot days, then for a couple of days after planting, the plants can be additionally shaded. Zinnias are drought-resistant, but it is better not to subject newly planted seedlings to excessive stress. In the future, zinnias are watered only during prolonged droughts, avoiding the loss of decorativeness and focusing on sagging leaves. nine0003

The first top dressing can be carried out no earlier than 3-4 weeks after planting. If strange spots appear on the plant or the leaves begin to wither and crumble after the resumption of growth, it is worth removing the affected leaves and treating them with systemic fungicides.

Zinnias are planted in individual holes, with large continuous plantings - in order. © Thompson-Morgan

Sowing zinnia outdoors

Even in the south, where winters are much milder, sowing directly outdoors is not considered the best option. But if desired, it can be held in the period from the second decade of April to mid-May. For the middle lane, only the end of May and the beginning of June are permissible, when the age-related frosts leave. nine0003

Sowing is best done immediately in a permanent place. Sowing on seedling beds with subsequent transplantation of plants will further delay the beginning of flowering.

Seeds are sown shallow, in individual holes at a distance of 10 cm, 2-3 seeds or in grooves with a similar distance. It is desirable to make crops uniform and sparse, but extra plants can then be removed or planted during thinning.

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