How to Grow Zinnias

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Zinnias will forever hold a special place in my heart. They are the ones who got me into flower gardening.

I never bothered with growing flowers. Never had enough time for them, and always preferred to use my garden space to grow vegetables, after all, vegetables are much more useful.

How to Grow Zinnias

This spring, my little girls (5 and 3) asked me to grow flowers. They love butterflies and other insects and they love picking flowers.

I knew nothing about flowers, but this year I had enough space to plant whatever I wanted since we started planting on our 20 acres in the country. It wasn’t just my small urban garden anymore, I could go crazy and plant whatever I wanted and if something didn’t grow it wasn’t a big deal.

So I thought I’ll get flowers that the girls can make a nice bouquet from, that will attract beneficial insects to pollinate the vegetables, and that will add some color to the garden.

How to Grow Zinnias

Since I got all my vegetable seeds from Johnny’s Selected Seeds, I wondered over to the flower section and started looking around. I came across a beautiful bouquet of Sunbow zinnias and knew right away that my girls will love them.

I ordered some seeds, tilled a 100 feet row right next to the corn on the edge of the field (you can see the corn in the picture above on the left), and planted the seeds.

Considering I had an acre of vegetables to take care of, I completely forgot about the flower seeds in the ground.

How to Grow Zinnias

Then one summer day there was an explosion of color on the farm and no one cared about the vegetables anymore.

I could barely remember how the flowers got there. I didn’t even water them once, but they still grew so dense and colorful. My girls were in zinnia heaven, and I had to admit… It was hard to concentrate on the vegetables.

Since then, flowers are on my list. I now try to learn as much as I can about flower gardening and what flowers I should choose for my garden.

But before I move on to learn about other flowers, I wanted to write down and share with you everything I found out about zinnias.

Plant Description and History

Zinnias are named after Johann Gottfried Zinn, a german anatomist and botanist who in his short life (1727-1759) grew the flower that was found in the New World and brought to Europ.

Zinnia is an annual, sun-loving plant native to Mexico, Central America, and the southwestern US. It is a member of the Asteraceae family, making it a relative of marigolds, cosmos, sunflowers, and daisies.

There are many verities of zinnias, some dwarf varieties and some that will grow a long narrow stem five feet tall (California Giant). Flowers grow in a wide verity of colors and can be as big as 6” across.

The vibrant colors attract many beneficial insects like butterflies, bees and bumble bees. Plant zinnias and watch your garden come alive.

Four Main Types of Zinnias

How to Grow Zinnias

Single – single zinnia flowers are the ones that have one row of petals and a visible center. They are the daisy-like zinnias. Those are the first zinnias that were discovered in Mexico by Spanish colonist.

How to Grow Zinnias

Double Zinnias and Semi-Double – This kind of zinnia has many rows of flat petals that come all the way up to the center of the flower. They come in a wide verity of colors and some even have beautiful stripes like this peppermint stick blend.

How to Grow Zinnias

Dahlia – it’s sometimes hard to distinguish between the double zinnia and the dahlia-like zinnia. The dahlia-like zinnia also has many rows of petals that come all the way to the center of the flower, however, the petals are a bit rounded upwards at the edges like the petals of the dahlia flower.

How to Grow Zinnias

Cactus – this type of zinnia also has double and semi-double flowers, but the petals are not flat. Instead, they twist and curl to form a fuzzy-looking flower. Here is a cactus zinnia seed blend from Botanical Interests. I didn’t try those yet, but it looks like a fun flower to grow and the butterflies love it.

How to grow Zinnias

Planting

I am going to share here with you what the book says about planting and caring for zinnias. All the good information about soil requirements, spacing and so on. However, I have to be honest, I did nothing of that. The zinnias that you see in the first three pictures of this post were sown in soil that no one worked for several years and had very little organic matter. I didn’t water, fertilize or thin my zinnias.

I am sure that if I had done all those things, my flowers would have probably been much bigger, maybe the colors were more vibrant. Anyway, I am just saying this to show you that this is truly an easy flower to grow, even if you don’t go by the book, you’ll still enjoy great flowers.

Direct Seeding – zinnias don’t like to be transplanted. If you live in a warm area with a long growing season, plant zinnia seeds directly in the garden about three weeks after your last frost.

If you want to be more precise and ensure maximum germination, check your soil temperature before planting. Zinnias will germinate within 3-5 days when soil temperature is 80-85F (and slower if soil temperature is lower).

Checking your soil temperature is not as big of a deal as it might sound. Take a walk to the garden with your kitchen thermometer, stick it in the soil and read the temperature. If it’s too low, wait another week and check again.

Plant zinnias in full sun, in soil that is well-drained, loose, fertile, and rich in organic matter.

You’ll need to space seeds or thin plants 6”- 18” apart depending on the variety you purchase. Cover seeds with 1/4 inch of soil and keep soil moist until plants are established.

Transplanting – if you live in a colder area with short growing season, you’ll have to start zinnia seeds indoors. Since zinnias don’t like to be transplanted (transplant shock can revert double zinnias back to singles), it’s a good idea to start the seeds in peat pots that can be directly planted in the garden.

Use good seed starting soil mix and keep soil at 70-80F. To do this, you might need to use a seedling heat mat.

Fill pots with soil, place few seeds in each pot and cover with 1/4 inch of soil. When seedlings are one inch tall, thin them to two plants per pot by cutting the seedlings with scissors at soil level so you don’t disturb the roots of the remaining seedlings. Wait until seedlings are 3 inches tall before transplanting to the garden.

When transplanting to the garden, space pots in the correct spacing according to the verity of zinnias you are planting, then wait a couple of weeks to see that your plants are growing before thinning one of the seedlings in each planted pot.

Planting Zinnias in Pots – you can grow zinnias in pots. Make sure to choose a pot that has at least one drainage hole and use good potting soil. It will probably be better to choose a verity that doesn’t grow more than 3′ tall and to plant just a few seeds per pot (3 seeds for a 10” pot, for example). Make sure to place your container in full sun.

How to Grow Zinnias

Caring for Zinnias

Watering – zinnias like to be well watered but don’t like waterlogged soil. Keep soil moist when you first plant until plants are established. Then, as a rule of thumb water one inch per week (o.6 gallons per square feet). I keep a simple rain gauge like this one in my garden and check  (and empty) it on the same day every week. If we didn’t have enough rain, I water my garden.

Disease and Pests – zinnias don’t have any major pest or disease problems but are susceptible to mildew which is caused by wet and humid conditions and can cause flowers to discolor or the plant to wilt.

To lower the chance of mildew don’t over water plants. Instead, water at ground level and keep the foliage dry. Another way to minimize the chance of mildew is to thin and space plants correctly to increase air flow around the plants.

Deadheading – Make sure to come by your zinnias every few days and remove old flowers. This will keep the plant attractive and encourage it to produce more blooms.

Staking – some verities of zinnia grow very tall. My zinnias were about four feet tall, but I think that because they were planted so close to each other they acted as a big support system for one another. If you see that your plants start to fall, you might need to stake them.

Fertilizing –  I use Espoma fertilizers for everything in my garden. This is a slow release, organic fertilizer that is made right here in America and the plants absolutely love. Since it is slow release you lower the chance of burning your flowers and you usually need to apply it just once during planting. You can use their Flower-Tone for zinnias. Learn more about choosing organic fertilizers here.

How to Grow Zinnias

Harvesting Zinnias

You can enjoy your zinnias in the garden, but the nicest thing about this plant is that it won’t harm it if you pick flowers for a table top arrangement. In fact, because the seeds are in the flower, and the plant is geared towards making seeds, once you cut a flower off the plant will produce more flowers to cover the loss of seeds.

For long-lasting arrangement, cut flowers early in the morning. Use a sharp knife or scissors to cut the stem right above a leaf node or a bud. This will encourage the remaining stem to keep producing more blooms.

When you leave the house to go harvest, take a bucket of cold water with you. As you cut the flowers, place them in the cold water right away.

Bring them inside to arrange. Remove the lower leaves and cut the end of the stem at 45-degree angle.

Fill a vase with one quart of warm water (100-110F).

Now, make your own cut flower preservative by adding:

1 tablespoon sugar

2 tablespoons fresh lemon juice

And, 1/4 teaspoon bleach

Stir, arrange your flowers and place them in a cool place that has good sunlight but not direct sun. You can add 1/4 teaspoon bleach to the water every 4-5 days. Your zinnias should last about three weeks.

How to Save Zinnia Seeds

The seeds of the zinnia are at the end of each petal (they connect the petal to the cone of the flower). You need to let the flower dry on the stem, then, the easiest way to do this is to cut the dry flower off the plant, and then cut the dry petals off (almost like giving the flower a haircut). You’ll be left with a the center cone full of the arrowhead seeds. You can keep them on the cone or collect them in a bag or small container until next year.

If left to dry in the garden, zinnias will reseed themselves. So if you want to have “free” zinnias growing in the same spot next summer, leave some flowers on the plant and let them dry. We ended up bush hogging the corn and the zinnias so I think now we have the whole area full of zinnia seeds. This can be interesting. We’ll see what happens next year.

It was completely by accident that I choose the easiest flower to grow for my first time growing flowers. It’s the perfect flower for any gardener, beginner or experienced. It’s not picky, very forgiving, doesn’t have any pest problems, full of color, and you can pick as much as you want. Realy, what else can a gardener ask for?

‘Till next week…

~Lady Lee~

How to Grow Zinnias

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12 thoughts on “How to Grow Zinnias”

  1. I really enjoyed your info on zinias plus the info on herbs. Very educating. My grandkids and I plant xinna s
    Every year here in W C Indiana. This is my second year playing with herbs. Keep up the good work. Put me on your email list. Thanks. Ray Davis

    1. There are about 50 seeds in the smallest pack of Sunbow Zinnias from Johnny’s seeds. You should plant 6 seeds per square foot. I just dug a little trench and sprinkled the seeds in it. You probably want to put them 3” or so from each other.

  2. I planted my zinnia seeds late this year. They are about 2 -3 inches tall with no flowers. I wanted to give some plants to my sister. Can I very carefully take a spoon and lift some out to put in a pot without harming the flower.
    I bought zinnias from the nursery and transplanted them and they are surviving.
    Any tips.

    1. Yes! You can do that, shouldn’t be any problem.
      My mother in law starts all her plants this way. She plants them in a little bed at one corner of the garden and as the little seedlings grow she digs them out and moves them to the garden.

    2. By the way, I planted mine late as well this year. They are a foot tall. I have a two hundred feet row of them and I can’t wait for it to become a colorful mess!

  3. I also started with zinnias by accident. I ordered some seeds for the flower bed outside my rental house in the city. When we purchased our farm last year, I had a lot of seeds left over from the year before, so planted them in front of the sorghum in our garden. The bees and butterflies loved them. Our whole garden was well pollinated thanks to the zinnias. They are absolutely beautiful and HUGE. I saved some seeds and replanted this year. I have a 30’ x 4’ area full of zinnias that are absolutely taking off. Each flower produces an extraordinary amount of seeds. I let them dry on the plant at the end of the season, then crush them in a bowl and winnow out the chaff. I had so many seeds, I even packaged some as Christmas gifts. There is seriously no easier or more beautiful flower to grow.

    1. I should start collecting the seeds… I usually just leave the flowers in the field to fry and they reseed themselves. It’s a great idea to use them as a gift!

  4. I absolutely love zinnias,i plant them every year ,so easy to grow and so beautiful in the flower bed or a flower arrangement.My grandchildren enjoy helping me sow the seeds than they are so excited when the plants appear and over joyed to pick the flowers. We love the pretty butterflys that visit the flower garden daily such a joy to watch.Thanks for the great information on my favorite flower.

    1. They are my favorite too! I planted many seeds in my field this year but then I left the farm for five weeks to go visit family in Israel. The weeds took over and not many zinnia plants managed to grow between them. I miss them terribly! I’ll have to wait for next year to have them again.

  5. Sorry to hear no zinnias this year,but I emagine you enjoyed your time spent with your family in Israel I’ve always wanted to go there.My zinnias are doing well i’m really surprised with as hot as it’s been i’m having to water them every other day,it;s been very hot and humid here in the south. Thanks for your reply sorry I took so long to get back,enjoying your site looking forward to coming here.Thanks!

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