How To Care For Zinnias in Pots [Keeping them blooming]


Growing zinnias in pots is not significantly different from growing them in gardens. In today’s post, I will be sharing tips on how to care for zinnias in pots. These native Mexican plants are quite easy to cultivate and care for. They bloom throughout their growing season producing bright flowers of different colors depending on the variety.

For reasons like limited or zero garden space and the absence of sunlight in the garden, many gardeners opt to grow zinnias in pots. With potted zinnias, gardeners can add lots of colorful greenery to indoor spaces or patios.

Like all plants, the trick to having thriving zinnias is linked closely to how they are cared for. This is very crucial to getting beautiful flowers which is the main objective of growing them in the first place for the majority of folks. This article would discuss everything you need to know about caring for potted zinnias. So read on to find out how to ensure you have statement potted zinnia blooms throughout the summer growing season.

How To Care For Zinnias in Pots

Related to sunflowers of the daisy family, matured zinnias come with beautiful white, light green, yellow, orange, red, or purple flowers. There are several species with Zinnia elegans being the most common. The easy-to-grow flowers are great as potted plants in urban balcony gardens.

Caring for potted zinnias is all about getting the fundamentals right. Fortunately, these won’t take you out of your comfort zone in terms of regular garden routine. But before settling into the business of how to care for your zinnias, you’d have to plant them the right way.

So we’d first take a look at some of the things that must be in place when growing zinnias in pots, before discussing how to care for zinnias in pots.

Considerations When Growing Potted Zinnias

Zinnia variety

While all varieties of zinnias can be grown in pots, shorter and dwarf varieties do better in pots or containers. Some awesome choices can be found in the hybrid varieties with their short and spreading growth cycle.

Zinnias that are great for pots include Zahara, Thumbelina, Small World, Dasher, Raspberry Lemonade Mix, and Solcito.

How Tall Do Zinnias Grow?

Pot size

Generally, as long as the pot is at least 6 – 8 inches in depth, there is no reason your zinnias won’t thrive. And if you are sowing a single plant in each pot, you could choose a pot that is also about 6 inches across. For multiple plants, use a wider pot.

That said, root spreading and the overall size of the plant depends on the variety.

Drainage

Adequate pot drainage is also a critical consideration when growing zinnias in pots. Planter pots bought from garden stores typically have drainage holes already. But decorative pots are unlikely to have them. So you want to drill some holes at the bottom if you are using decorative pots or containers.

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Soil

Though zinnias can adapt easily to almost all types of soil, the perfect soil for growing zinnia in pots should well-draining and rich in organic matter. If you are using garden soil, you could amend it by adding perlite to improve drainage and aged compost for additional nutrients.

You can also use a standard potting mix and then add compost to the soil to infuse nutrients to make the soil more fertile.

To cover all bases in terms of the soil, testing the pH level of the soil is recommended. The ideal zinnia soil pH level is between 5.5 and 7.5. The aim is to keep the soil slightly acidic. If the pH is not within that range,  amending it with some peat moss should resolve the issue.

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The Best Time to Grow Zinnias

The consensus, universally, is that zinnias are some of the easiest annuals to grow. However, much of your success would depend on choosing the right time to plant them. As annuals, the growth cycle lasts just a year. This makes it imperative to start early.

There are a couple of options available: such as whether you want to start as early as possible or wait until the threat of winter frost is unlikely.

For the earliest possible start, it is recommended that you plant the seeds indoors about a month and a half before the final spring frost. You can plant them right in the pots. This gives the zinnias a big head start in terms of early development. Starting seeds indoors also improves the rate of germination.

Keep in mind that if the final destination of the potted zinnias is outdoors, transporting the young plants might be stressful to them. The temperature differential between the warm indoors and cold outdoors can be too much for some of the young plants. So it’s best to introduce them gradually to the outdoors by placing the pots in shaded areas for a few days first.

If you want to start you planting the seeds outside, you have to wait until there is no sign of frost.

Generally, the ideal temperature for growing zinnias is around 60°F. But since daily temperature fluctuations are the norm, you are looking at a temperature range of between 75 – 85°F.

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How to Care for Potted Zinnias

Seedlings

Care for planted zinnia seeds in pots involves covering the seeds with a bit of soil. A quarter-inch of the soil should be enough. Ensure that the soil is warm and moist all the time.

When the seeds sprout, it is important to place the pots in a sunny spot. If the seeds were planted indoors, you can take the pots out after about 5 weeks. But introduce them to the outdoors gradually by first placing them in a bright but shaded area for about a week.

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Watering

The soil must always be moist so you need to water regularly. But be careful to avoid over-watering that can lead to deadly root rot. Aim at finding a balance between keeping the soil moist and how often to water the zinnias.

Generally, depending on the weather conditions, zinnias need about an inch of water per week. In hot conditions, you might have to water more if the soil becomes dry before the week elapses.

The best way to stay on top of the situation is to frequently check the soil moisture level. Simply stick a finger into the soil. If the top one inch is dry, the soil needs water.

And when watering, ensure that the stream of water doesn’t touch the leaves. Focus on watering the soil or base of the plant. Water on the leaves or flowers can lead to fungal diseases.

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Sunlight

Place the pots where they can get lots of sunlight every day. The plants need at least 6 hours of sunlight for excellent blooming.

In warmer regions though, you might want to move the plants out of the full glare of the sun to a partially shaded area for a bit of relief. But no matter how hot the weather is and the subsequent need for shade, always aim for a total of 6 hours of exposure to sunlight daily.

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Support

If you are growing taller zinnia varieties in pots, you might need to bury a stake close to each plant to provide support. This ensures that the plants remain straight while growing.

Fertilizer

Zinnias would benefit from a light application of fertilizer.

If it becomes necessary to use fertilizer, a 5-10-5 water-soluble product is recommended. This mix is low in nitrogen and potassium that is good for zinnias. The high phosphorus content in the fertilizer would aid in processing nutrients into plant energy.

To keep the fertilizer schedule uncomplicated, apply the fertilizer when watering the zinnias.

Tips:

  • Whatever the normal fertilizer strength is, dilute it by adding 4X as much water to avoid causing overgrowth.
  • You can apply fertile when the zinnias are about 4 inches tall.
  • In the middle of summer, you can apply a second fertilizer helping to re-invigorate the plant.

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Air circulation

When growing zinnias in different pots, one issue that could be a problem is air circulation. Lack of space for air to circulate can lead to diseases especially if exposure to the sun is a problem.

Circulating air helps to dry excess soil water in the absence of sunlight. And with enough space, the plants can breathe better.

So when placing the pots, ensure there is enough space between the pots. And it would be a great idea not to plant too many zinnias in one pot.

Deadheading

Remove old and spent or fading flowers to promote newer growth and the production of more flowers. Deadheading also helps to extend the blooming season.

Use sharp sears to cut off the stem below the old flower making sure to avoid flower buds. Clean the shears in rubbing alcohol after deadheading each flower to prevent the spread of diseases.

How to Deadhead Zinnias in Pots

Controlling pests and diseases

Though zinnias are usually free of pest problems, they sometimes face attacks from aphids, mealy bugs, mites, and caterpillars. In terms of diseases, they can be susceptible to wilt, powdery mildew, and bacterial or fungal spots.

Prevention is simply about ensuring adequate airflow in and around the plants and watering the base of plants only.

If there is a disease infection, handpicking infected zinnias is one way to deal with this problem. You could also spray neem oil solution on them. But the use of neem oil is sort of like a last resort. As long as the care routine is maintained, this won’t be necessary because diseases are rare in zinnias.

Wrapping up

The beautiful zinnias are not hard to grow whether in pots or the garden. It only takes about sixty days for the plants to start blooming after planting.

Before the blooming though, taking care of the potted zinnias is necessary even if they are famous for adapting easily to all types of conditions. That said, care for zinnias in pots is pretty straightforward. The water, sunlight, soil, and nutrients requirements are stuff most gardeners are used to dealing with on a daily basis.