No garden is complete without zinnias. Once you discover how easy it is to grow beautiful zinnias in your vegetable or flower garden, you’ll be as hooked as I am!
In this post, I’ll cover how to grow zinnias from seed, my favorite zinnia varieties, where to find good zinnia seeds, and also when to harvest zinnias.
Why Grow Zinnias?
Zinnias bring in pollinators of all kinds: bees, butterflies, and hummingbirds.
One of my favorite things to do to enjoy the garden is sit next to the zinnia patch and watch all the different pollinators coming and going.
Pollinators are important to every garden. Even if you only want to grow vegetables, you will find that you’ll have more productive plants if you have plenty of pollinator-attracting flowers growing throughout your veggie patch.
Zinnias are beautiful and come in several different colors. They also last a long time both in the garden and in the vase.
There’s no easier way to add color to your garden than by growing a few zinnias.
How to Grow Zinnias from Seed
Zinnias take around 80 days to mature, or begin blooming. They also bloom best in full sun—8+ hours of sun.
Wait to plant out your zinnia seeds or seedlings until your temps are consistently above 50°F (10°C).
Seeds can be sown anytime during your warm growing season as long as there are 80 or more days left in the season (before your first frost). I explain more about frost dates in this post.
Sowing Zinnia Seeds in Seed Trays
You have two options when growing zinnias from seed: starting them in a pot or direct sowing.
Zinnias sprout and transplant fairly easily, so if you want to keep a close eye on your seedlings, you can start seeds in a small pot and transplant the plant once it has two sets of true leaves. This usually takes 3-4 weeks.
Do not wait too long to transplant seedlings or they will become root bound and won’t grow well.
To do this, fill the cells of your seed starting trays with light, fluffy potting mix.
Use your finger to make small depressions in the center of each cell about a quarter inch deep.
Place two zinnia seeds in each cell. Cover with soil and water gently until water runs out the bottom of the cells.
Keep the soil moist until you see germination. The little seedlings are just so cute!
Direct Sowing Zinnia Seeds
However, I think direct sowing is the best way to grow zinnias.
Make sure the ground is well-prepared with soft, fluffy soil.
Remove rocks and sticks and add a thin layer of compost or bagged garden soil if you want.
Check the back of your seed packet for the specific spacing and planting requirements of your plants.
But in general, you will plant two seeds in small holes 1/4 inch deep. Space zinnias 9-12 inches apart in a row.
You can grow zinnias closer together—6 inches max—if your plants have good airflow around them.
Keep the seeds moist by misting the soil every day until they sprout.
Water lightly for the next few days, then switch to watering only when the top 3 inches of soil is dry. Zinnias prefer to be more dry rather than too wet, so be mindful of your watering habits.
In less than two months, you will see zinnia blooms!
Zinnia Plant Needs
One thing that zinnias need is good airflow.
Zinnias are susceptible to powdery mildew, but having space around the plants for air to move can help keep powdery mildew at bay.
Zinnias don’t need a lot of nutrition to grow, but they will bloom best with some fertility. Add a layer of compost or sprinkle a handful of balanced organic fertilizer around the plants.
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My Favorite Zinnias to Grow
Zinnias come in a variety of colors, shapes, and sizes.
Colors range from red, orange, pink, yellow, white, and purple. Shapes can include cactus, beehive, “dahlia,” single, double, semi-double, and scabiosa.
And sizes range from less than 1 to 4 inches.
There are short zinnias (as short as 8″) and zinnias as tall as 4 feet.
I haven’t grown every type of zinnia (yet!), but of all the varieties I’ve tried, these are my favorites.
- Queeny Red Lime: Long stems, beautiful antique red color with lime green petals in the center, lasts all season
- Queeny Lemon Peach: Same as Queeny Red Lime, but with warm, yellow orange tones
- Benary’s Giant: Big ruffly zinnias with long stems
- Alpenglow: A new zinnia variety from Floret Farms in a unique pastel shade
- Señora: Warm salmon color, large blooms and interesting twisted, shaggy petals (For some reason mine did not have the twisted petals this year, so I don’t have a photo of that.)
- Lilliput: Long, thing stems when pinched, cute little blooms that look like little beehives
These zinnias all produce long stems, but there are shorter stemmed varieties for the front of the border, if you prefer that.
I have also grown these short zinnias and would recommend them all.
- Jazzy Red
- Profusion Series
No matter what style of garden you prefer, chances are there’s a zinnia for you!
Where to Find Zinnia Seeds
Check your local nursery or garden center for zinnia seeds. I like shopping online for seeds as well and would recommend these seed companies.
- Baker Creek Heirloom Seeds
- Botanical Interests
- Pinetree Garden Seeds
- Floret Flowers (They often have limited quantities of seed, so get on their mailing list if you want to purchase from them.)
- Hoss Tools
You can also see if your local library hosts a seed swap or has a seed library where you can “check out” seeds.
Once you have started growing zinnias, I recommend saving seeds from your favorite blooms to grow out the next year!
When to Cut Zinnias for the Vase
If you are growing zinnias to cut for bouquets or arrangements, then do the wiggle test before you cut the flowers.
Hold the zinnia stem several inches below the flower. Wiggle the stem.
If the flower is stiff and upright, it is good to cut. If the flower stem is wobbly, leave it for another day or two and then test again.
Deadhead spent blooms (cut dead flowers off) to keep zinnia plants blooming all season long.
Also note, if you are growing multi-layered zinnias like Queeny Red Lime or Lilliput especially, wait to pick the flower until several layers of petals have emerged.
Picking them too early will result in flatter blooms, while waiting to pick will give you more full, rounded shapes that resemble a ball dahlia.
Looking for More Content on Cut Flowers?
These are other posts I’ve written on cut flower gardening. I hope these help you grow the best flowers!