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Summer Flowers: Zinnias

A bucket full of zinnias, pink, orange, purple, and lime green

The quintessential summer annual, zinnias are an easy flower to start growing even if you have never grown flowers before.

If you were to make a list of flowers to use when starting a flower farm, zinnias would make that list because they are so easy to start from seed. There are so many interesting and beautiful varieties of zinnias, there is something for everyone.

A bee in a pink zinnia with more zinnias in the background

Our Story

Even our first year farming, after preparing the beds and planting vegetable seeds, I saved space for zinnias. That first year, I started the flowers by seeding them directly in the flower bed. I dropped seed onto the ground, covered them up, and waited. While birds definitely ate up my sunflower seeds, they left the zinnia seeds alone. Before long, I was amazed to see sprouts from the zinnia seeds. That summer, we had a beautiful mix of colors from a packet of seeds. Many of those flowers reseeded themselves and popped up the next year.

While I do like zinnias, I decided last year that I was not sure about growing them again. They always get powdery mildew and are the first crop to succumb to it each year. I planted two successions last year, both started indoors in soil blocks. The first succession was planted out as soon as it was warm enough for the seedlings. The second was planted out in late June. My first succession started out beautifully but was hit with powdery mildew in early July when we had daily rainfall. The second succession did much better and was able to ward off the powdery mildew until late August.

That experience helped me decide to make some changes this year. This year, I started zinnia seeds by direct seeding them in the field and not by starting them in individual soil blocks indoors. Also, I sowed seeds in mid to late June.

My plan is to use a milk and water spray to prevent powdery mildew for as long as possible, but also to grow the zinnias so that they are mature during a dryer season here in NC.

A bed of zinnias, pink, orange, and coral

Care & Maintenance

Zinnias are an annual that need full sun. They can be started indoors in soil blocks or your preferred method of seed starting, or they can be sow directly into the ground. If you start seeds indoors, you are able to sow seeds earlier to time the planting out of the seedlings with weather that is warm enough to sustain annuals. Zinnias take about 60 days from seed to flower, so there is still time to sow seeds.

Sow seeds 1/4" deep and lightly cover them with soil. Once seedlings have sprouted and have grown to have a few sets of leaves, if you sowed directly into the soil, thin the rows of zinnias to a plant every 8-12" by snipping the plant at the soil line. This is important as it provides good air circulation for the plants and decreases the potential for powdery mildew.

Sow seeds in successions for an ongoing harvest of zinnias. Pinch zinnias when they have three sets of leaves to get more blooms. Pinch above the first leaf set.

Make sure to deadhead spent blooms so that the plant continues to flower. You can snip at the base of the bloom or cut down into the plant above a set of leaves.

A handful of pink, yellow, and green zinnias


There is a specific stage at which one should harvest zinnias. Gently shake the stem to see if the flower bends and wobbles on the stem or if the stem has strengthened and the flower does not wobble. Once the stem does not bend with the flower, it is ready to harvest.

Harvest zinnias early in the morning or in the cool evening. Harvest into a clean bucket of water using clean and sharp snips.

For longer stems, begin by harvesting deeply into the plant. Holding the flower head, reach down the stem to the second or third set of leaves from the flower. Harvest above that set of leaves. The plant will send up shoots at those leaf sets and develop long stems.

Strip the leaves and side shoots from the harvested stem. Make sure to dispose of leaves that have any sign of powdery mildew by placing them in the burn pile or garbage. Powdery mildew only survives on live plant material, but I prefer to be careful and burn plant debris rather than composting it.

A sunny bed of zinnias

Other things to consider

Other benefits of zinnias are that they are deer resistant, and smaller zinnias dry well.

Additionally, zinnias are a popular flower, right now, for breeding. Floret has an incredible breeding program where they are developing some amazing new varieties of zinnias.

Another person to learn from is Blomma Flower Farm. She has instructive and informative videos that she posts about saving seed and all the small details in between. She also has a book that goes into detail about breeding zinnias.

If you get a beautiful zinnia with lovely color or shape, make sure to save seeds.

There is always more to learn, and zinnias are a great example of a whole new set of skills that could be learned to develop new flowers.

A row of zinnias

This post is part of a year-long series on flowers and plants that we love and grow on the farm. Check out other flowers that we love.


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