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How to Plant Zinnia Seeds in 5 Easy Steps

Do you want to learn to grow beautiful flowers, or simply add low-maintenance color to your outdoor space?

Planting zinnia seeds is a great choice whether you’re an experienced gardener or just getting started. There are infinite varieties to suit any of your preferences, with many different colors and bloom types.

Zinnias are very simple and forgiving to grow from seed, and the payoff is totally worth it.

Zinnia flower

Follow this guide to learn how to plant zinnia seeds and grow them into zinnia seedlings.

Why You Should Grow Zinnias

Zinnia seedlings

If you’ve ever seen zinnias, and you probably have even if you didn’t know it, you’re familiar with how colorful and beautiful they are.

The best part is, they’re very easy flowers to grow and you can choose whatever colors you like best! They come in just about every color except blue.

They look amazing in your garden and attract lots of pollinators, so you’re helping the environment by planting zinnia seeds.

Zinnias will grow all season long and require very little maintenance. You can even collect the seeds at the end of the season so you’re ready to go the following year.

They also do a great job of brightening up your home decor in a bouquet and last a long time once they’re cut. You can also grow many of the smaller varieties completely indoors.

Where to Get Zinnia Seeds

How to plant zinnia seeds

Part of what makes planting zinnia seeds so simple is that they’re very popular and common. This means it’s pretty easy to find them in lots of different varieties. They’re also very affordable.

Make sure you’re starting with the right seeds; Hoss Tools has plenty of colors and types for you to choose from. True Leaf Market is another great place to check out so you can start planting zinnia seeds right away. We love both of these vendors for their range of options, and you’re sure to get high-quality zinnia seeds.

How to Plant Zinnia Seeds

Dried Zinnia flowers

You can plant zinnia seeds inside or out, depending on your climate and how long you want your growing season to be.

Smaller varieties can be grown in pots inside or outside as well. If you do want to keep them in pots, choose larger growing containers so make sure your zinnia seedlings have plenty of space to grow.

Starting Inside

If you have the space available in your home, planting zinnia seeds inside to start is a great option because it extends your growing season. This way, your zinnia seedlings get a jump on their growth in a warm, safe environment before they’re ready to go outside.

Check when the last hard frost will be in your area; you can get started planting zinnia seeds 4 to 6 weeks before that date.

Get some seed trays and add soil, or use pots that can later be transplanted directly into soil. Make a small hole, only about 1/4 inch deep, drop a seed in, and cover very lightly. To get your seeds to sprout into zinnia seedlings they’ll need lots of sunlight, so place them in a spot that gets sun all day long.

Keep the soil moist to help the seeds germinate successfully. The hard outer shell of the seeds will need consistent moisture to soften up enough to open up as each sprout grows.

Once the last frost has passed, your zinnia seedlings are ready to go outside. Pick an area that gets full sun and use fertilized well-draining soil.

Planting Seeds Outside

While it will likely give you a shorter growing season, planting zinnia seedlings outside is preferable to transplanting because it’s easier on the plants.

Make sure you’ve waited until after the last frost in your area before planting and choose an area with lots of sunlight.

Plant your zinnia seeds into fertilized soil with good drainage. Space each seed a few inches apart in a very shallow hole, covered lightly with dirt. Keep the soil moist to allow the seed to soften up and sprout.

When to Plant Zinnia Seeds or Seedlings

In total, it will take about two months for zinnias to grow from seed to flowers. They’re annuals, which means they can’t survive when the ground freezes and will need to be replanted each year.

It’s crucial that your area will not have any more frost or freezing temperatures or your zinnia seeds won’t grow successfully.

Zinnias will grow through spring, summer, and early fall.

Caring for Zinnia Seedlings

The best way to ensure you end up with strong, healthy plants and colorful flowers is to properly care for your zinnia seedlings.

You’ll want to maintain a steady level of moisture in the soil, being careful not to overwater. Zinnia seedlings prefer well-fed soil, so you can also add compost periodically to give them the nutrients they need.

Once your zinnia seedlings reach a height of 2 to 3 inches tall, thin out the weaker plants so the remaining seedlings are about 6 to 8 inches apart, or a foot apart for larger varieties.

You can also pinch them back as they grow and deadhead the spent blooms to encourage your zinnias to flower more.

Collecting Seeds

If you loved growing your own zinnias, be sure to collect the seeds at the end of the season. Zinnias have lots of seeds, which means you’ll only need to harvest from a few blooms.

Annuals need replanting each year, so saving your seeds will give you free seeds for the following spring.

All you have to do is let the flower heads dry out, shake or pick the seeds out, and air dry them. Store in a cool, dry place and you’re ready to go!

Get Your Hands Dirty

The best thing about these flowers is that it doesn’t take years of experience to learn how to plant zinnia seeds.

Planting zinnia seeds is such a rewarding experience. Try it with your kids or start your own patch of zinnia seedlings and get ready for a burst of color.

Interested in more zinnia content? Visit our zinnia page for more growing tips, care guides, bouquet suggestions, and more!

Getting started on your seed growing journey? Use my seed starting guide to find care guides, helpful tips, product suggestions, and more!