Zinnias are the perfect flowers for summer gardens. Easy to grow, available in just about every color, and best of all, long-blooming. The blooming season for zinnias will keep you in flowers all summer long, especially with a few tricks to extend that window as long as possible.
Zinnias will bloom for about two months before their flower production slows down. Gardeners can extend the bloom window by succession sowing a new planting every 2-4 weeks so that new plants come into bloom as the old ones stop producing flowers.
With a bit of extra care, you can enjoy zinnia blooms all summer long!
How long do zinnias bloom?
Zinnias will bloom for about two months per plant, starting in midsummer once the weather has warmed up. Each plant will produce continuous blooms until it succumbs to disease such as powdery mildew or the first fall frost.
However, with a bit of planning, you can turn that two-month window of blooms into four months or more with succession sowing.
Use succession planting to extend the blooming season
Succession planting is vital to keeping your garden full of blooms for as long as possible. If you’ve never heard of succession planting, it’s simply the practice of planting new seeds every 2-4 weeks so new plants come into bloom as the old ones stop producing flowers.
Here’s what it could look like for your summer garden:
|Last frost date||1st planting||2nd planting||3rd planting|
|April 15||May 6||May 20||June 10|
|First blooms||July 1||July 22||August 12|
The first planting on April 15th will probably wind down by the end of September, but your second planting will be mid-stride, and the third planting will have just begun blooming. This planting schedule means you’ll have fresh, productive plants giving you flowers from July to October or later with just three plantings.
3 tips to keep your zinnias blooming all summer long
You can use a few other tricks to maximize your growing season for a prolonged harvest of beautiful zinnia blooms.
1. Deadhead fading flowers
One way to keep your zinnias blooming all summer is to deadhead them. Deadheading means removing the spent flowers before they go to seed. If you don’t, the plant will put its energy into making seeds instead of blooms.
Pro-tip: At the very end of the season, leave a few flower heads to go to seed so you can harvest them for next year. Zinnia seeds are easy to save, and they’ll save you money next season.
To deadhead zinnias, use a pair of scissors or garden shears to cut the stem just below the spent flower. Be sure to cut at a 45-degree angle so that water can’t pool on the stem and cause it to rot.
Need some good clippers for the job? Check out my two favorite pairs.
My favorite garden shears
These two clippers can handle all the tasks (and the red handles help me keep track of them). Corona Leaf & Stem Micro Snips: Perfect for cutting small stems, deadheading spent blooms, or keeping the mint plant from taking over my garden. FELCO Classic Manual Hand Pruners are better for heavier-duty pruning, such as dead sunflower stalks, tomato vines, and cutting old zip-ties off the trellises.
Learn more about the how and why of deadheading in this article, Should You Deadhead Cut Flowers, Too?
2. Fertilize regularly
Another way to keep your zinnias blooming all summer long is to provide them with the proper nutrients. Zinnias are heavy feeders and will benefit from being fertilized every few weeks. Look for a fertilizer that is higher in phosphorus, which is the second number listed on the package, such as 2-8-4, and promotes bloom production.
Pro-tip: Tiger Bloom is an excellent organic liquid fertilizer option that I use in my garden every summer. It’s high in phosphorous, which is the macronutrient flowers need to produce as many blooms as possible.
3. Provide adequate water
Zinnias also need plenty of water to look their best. During hot, dry weather, water them every couple of days. Make sure to give them a good soaking each time, rather than just a light watering. Deep watering will help them stay hydrated and avoid wilting without encouraging shallow root development.
Pro-tip: Read more about best practices for watering your garden in this article, Daily Water For The Summer Garden? Not Necessarily.
How do you plant and care for zinnias?
Planting zinnias is an easy task that is an excellent start to any garden season. These flowers have a short list of requirements for optimal growth, although even then, they’re pretty flexible flowers.
Zinnias prefer full sun; however, they will tolerate some light shade. Zinnias are not particular about soil type as long as it is well-draining. It is often easier to start zinnias from seed directly in the garden, but they can also be started indoors and transplanted if you have a short growing season and want to get a head start.
Space your zinnias 9-12 inches apart when planting if you plan to cut from them regularly. If you want to mix them into your landscape and only harvest occasionally, spacing them 12-18 inches apart will give them more room to grow.
If you are transplanting zinnias, plant them at the same depth as in the pot or starter tray. Water the seedlings immediately after planting.
Zinnias need to be watered regularly, especially during hot, dry weather. Even with regular watering, you might see your plants look a bit droopy during the day. If that’s the case, don’t worry. They’ll bounce back once the day cools off.
On the off chance they don’t perk up, check out this article for more ideas of what’s going on: 5 Reasons Your Zinnias Are Drooping Or Wilted (Learn How To Fix It).
Additional resources on growing zinnias
If you’re looking for more information on growing zinnias, these articles are a great place to start: