How to Grow: Zinnias

Pronunciation: zinn-ee-ah

Ah, Zinnias… if I had a dollar for every time someone told me “I love Zinnias!”, I would be a rich woman. ;)

Zinnias are a well known, well loved, classic summer blooming flower. Their cheery faces are sure to brighten your day.

There is a lot to love about Zinnias… but unfortunately, they have a few strikes against them too.

Let’s look at the Pros and Cons of growing Zinnias for cut flower use.

PROS

They come in a multitude of colors and sizes (see photo below!).
They are easy to grow.
They grow from seed to bloom in about 80 days, which means you can direct sow them instead of having to grow transplants.
The plants are productive for a long period of time.
They are bright and cheerful in bouquets.
They have a good vase life of 5 -7 days, with proper harvest and care.

CONS

They are susceptible to Powdery Mildew and leaf spot (fungal and bacterial), which doesn’t always affect the flowers but leaves the plants looking nasty and unsightly.
They are a “dirty cut flower”, which means the stems will muck up the water in the vase in hours and shorten the vase life of all the flowers, unless preventative measures are taken (this is such a “con” for me that I don’t like to incorporate them into bouquets, as I feel they ruin the other flowers).
They are highly susceptible to Japanese Beetle damage.

“Benary’s Giants” Zinnias are truly giants!

CHOOSING SEEDS

Zinnias often come in bright, bold colors, but these days you can also find muted or dusky colors, which I appreciate. Some of those Zinnia colors are a little too intense for me!

Zinnias also come in a variety of flower sizes, ranging from the large “dahlia flowered” types (which I call “the poor man’s dahlia”. Ha!), to cute little button-like blooms. When choosing Zinnia seeds, be sure to choose varieties that will grow to at least 18” tall.

Here are a few of my favorite Zinnias to grow for cut flower use:

“Benary’s Giant” series (come in various colors)
“Uproar Rose” (expensive seed, but worth it for the disease resistance)
“Queen Red Lime”
“Queen Lime Orange”
“Oklahoma” series (cute little button blooms)

HOW TO SOW

Zinnias are heat loving, summer blooming flowers.

They do not like cold temperatures and can’t handle frost, so do not try to plant them too early in the season. They grow quickly when the soil warms up and begin to bloom around early/mid July.

Transplants or Direct Sow?

Zinnias are versatile and can be transplanted or direct sown.

Transplants are fine, but make sure the transplants are only a few weeks old (3-4 weeks). Larger, older transplants tend to be “root bound” and will be permanently stunted in their growth and vigor.

Personally, I find Zinnias grow faster, and are more productive and healthier when they are direct sown.

I’ve done trials, planting 4 week old transplants on the same day as direct sowing seeds. Within 2 months, the direct sown plants were BETTER than the transplanted plants.

You might as well save yourself some time and space, and simply direct sow the seeds!

To ensure I have blooms all summer, I usually so 2-3 sowings in the spring, spaced 2-3 weeks apart. For example, I start some seeds indoors in the spring. When they are ready to be transplanted out into the beds, I will also direct sow some seeds in another bed at the some time. 2-3 weeks later, I will direct sow more seeds.

PLANT SPACING

For cut flower use, Zinnias can be grown anywhere from 6-12” apart.

Closer spacing encourages longer, straighter stems… but too close and you risk increased disease problems. You’ll have to experiment and find out what works in your area!

GROWING ON

If flowers are harvested and spent blooms are “deadheaded” (removed), the plants will continue to send up blooms until frost or cold weather arrives (or Powdery Mildew takes them out!).

Remember: The whole point of growing flowers for cutting is to CUT ALL THE BLOOMS! ;) Keep cutting or the plants will stop producing.

STAGE OF HARVEST

Zinnias should be harvested when they are fully open. They will not continue to open after being cut.

It’s VERY IMPORTANT the bloom passes “The Wiggle Test”. Blooms that don’t pass the test will not hold up well.

To perform the test, grasp the stem about 8” below the bloom and wiggle the stem. If the bloom flops around, it’s not ready to harvest. If the stem remains rigid, the bloom is ready to be harvested.

As with all cut flowers, be sure to cut deeply into the plant between 2 sets of leaves, cutting stems at least 18” long. Deep cuts signal the plants to produce MORE flowers to replace the one you cut.

POST HARVEST CARE

Zinnias do NOT like to be placed in a cooler. After harvesting, allow them to rest in a clean bucket in a cool, dark spot, like a basement.

Zinnias are a “dirty flower” that will muck up the vase water unbelievably fast. Dirty water breeds bacteria, the enemy of cut flowers. Bacteria significantly reduces vase life.

To combat this, it’s important to use commercial flower food (easily found on Amazon - I like “Floralife”) or add 1-2 drops of bleach to the bucket or vase. Just a few drops, not an entire teaspoon. Too much bleach will actually bleach the color from the flowers! I know this from experience ;)

QUESTIONS?

Questions or comments? Leave them below and I’ll get back to you!

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