Fortunately for gardeners everywhere longing for flowers, zinnias are a fantastic choice when looking for a quick-growing bloomer. You won’t have to wait long until you have flowers for cutting, drawing in pollinators, and making your garden a pretty spot to spend some time.
Just how long (or short) will your wait be?
75 and 90 days to grow from seed to bloom. Optimal growing conditions of warm soil and full sun exposure will promote quick germination in 3-5 days, followed by fast growth to maturity. Dwarf zinnias may mature a few days faster in the 75-85 day range since they don’t need to grow as tall before blooming.
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How long do zinnias take to grow (days to maturity)
Regardless of the variety, most zinnias will mature in 75-90 days. Each variety’s height and growth habits will impact how long they take to grow, as well as the growing conditions.
|Days to maturity
|Benary’s Giant Series
|State Fair Mix
Zinnias love heat and sun, so save your best garden site for them if you’re looking for fast-blooming flowers. A garden bed or container with rich, well-draining soil and full sun exposure will net you the fastest growing flowers, not to mention the longest blooming season.
If you’re getting a late start and not sure if there’s enough time left in the season for your flowers, look at the days to maturity for your given variety and count backward from the first frost date in your region.
The date will tell you the last possible day that you can plant your zinnias and have them reach full maturity. You can also reference this handy article for some tips on how to maximize your season: Plant Another Round Of Zinnias (It’s Not Too Late).
Wondering how long a plant takes to grow usually means you’re impatiently waiting for those days to go by so you can get to see your first blooms. If that sounds like you, keep reading for tips on speeding up certain growth stages.
If you need to know for your garden planning, don’t worry; I’ve got you covered, too.
How long do zinnias take to germinate?
Zinnias will germinate anywhere from 3 to 10 days after you sow the seeds. If you start your seeds indoors on a heat mat, you will get the quickest germination in 3-5 days. If you plant seeds outdoors in cool soil, then the seeds probably won’t sprout for closer to 7-10 days.
Once the seeds have germinated, the seedlings will spend the next few days growing their first set of true leaves. These first few days after germination are crucial for your seedlings, so make sure they have enough water and sunlight or access to a grow light.
Germination is one of the phases you can optimize to speed up the growth of your zinnias. A heat mat will help speed up germination and initial growth.
How long do zinnias take to bloom?
Zinnias bloom as soon as 75 days after being planted, though some varieties may take closer to 90 days before the first flowers open. This will be sometime in July following a spring planting for most gardeners.
Variety selection and growing conditions will be the two most significant factors influencing the number of days it will take to go from sowing a tiny seed to seeing your first bloom of the season.
Dwarf varieyies may bloom slightly sooner than standard varieties due to their smaller size.
Dwarf varieties will generally take less time to fully bloom than taller varieties because of their shorter heights, but the difference could be as little as a week or so. Although, if you’re in a rush for blooms for an event or special day, that week can make all the difference!
Jazzy Mix: Red, yellow, pink, and orange double and semi-double blooms reach 20-26 inches and are quick to bloom. This compact variety makes it a perfect choice for containers and smaller gardens.
Persian Carpet: Although it’s not technically a dwarf zinnia, Persian Carpet will stay shorter at around two feet. The bicolor petals are burgundy, orange, yellow, and cream, making beautiful fall bouquets.
Most popular zinnia varieties fall within this category. Think of the vibrant red, orange, yellow, and purple flowers you see in market bouquets, and chances are those are a Benary’s Giant or State Fair mix.
These popular varieties will take up to 80-90 days to mature since they need to grow taller before blooming. The same can be said for the Queen series, one of my favorite varieties to grow. 11-12 weeks after planting, and I should be able to see those first buds start to crack open.
Oklahoma series: This variety comes in at three feet tall with smaller, fully double flowers that look a bit like pom-poms. These are excellent filler flowers and will bloom around 80 days after sowing.
Queen Series: One of the most popular zinnia series, Queen Lime varieties come in antique shades of Lime, Red, Orange, Blush, and Blotch. These varieties grow about 3-4 feet tall and bloom right in the middle range at around 80 days.
Benary’s Giant Series: Another florist favorite, the “giant” part of the name is accurate; this variety routinely grows up to four feet tall and produces large blooms up to six inches across. These flowers make an impact in the garden and the vase for months on end, though they bloom closer to 90 days more often than not.
State Fair Mix: At 3-4 feet tall, this mix produces large blooms in shades of pink, rose, lavender, white, and more. The flowers are more open than other varieties, with the center visible in each bloom. These tall flowers are excellent for cutting and are a favorite of garden pollinators. Worth the wait for blooms!
When do zinnias go to seed?
Zinnias will start to set seeds 3-4 weeks after the blooms open. Once the ends of the petals begin to look faded and worn out, you’ll know the flower has turned its focus to producing seeds. Eventually, the petals will dry out completely, leaving a crisp, brown flower head behind. The seeds are tucked into the center of the flower, under the dried-out petals.
Deadheading your plants will help extend the blooming window of your flowers. As long as you consistently remove the faded flowers, the plant will focus its energy on flower production rather than seeds, which will lengthen the overall blooming window from 1-2 months to three months or more.
To deadhead, cut the flower stem back to just above a pair of leaves, encouraging a new stem to appear that will produce another flower.
You might consider letting some of your zinnias go past their prime to set seeds instead of deadheading them. Leaving the flowers to go to seed will serve a different purpose, such as saving seeds or providing food and shelter for wildlife over the winter.
When should you plant zinnia seeds?
Zinnias are great garden flowers because they’re quick growers and have a wide planting window. Knowing how long each stage of growth lasts can help you plan for your season, especially if you’re succession sowing or trying to stretch your zinnia season.
If you’re in a warmer zone, like 7 or 8, you can plant your flowers outside around mid-April. Zinnias aren’t cold tolerant, so for direct sowing, it’s best to wait until the soil has warmed up thoroughly.
For colder areas in zones 4 or 5, you might wait until May to direct sow to avoid any risk of frost or snow.
If you’re starting seeds indoors, you can sow them six weeks before you intend to plant them out, which is a great way to maximize your growing season in colder climates.
Not sure when the best date is to transplant or sow seeds? You can punch your zip code into this website Dave’s Garden, which will display your first and last frost dates for your exact location.
For step-by-step instructions on how to plant zinnia seeds, keep reading this article for all the details: Germinate Zinnia Seeds Indoors: Tips and Tricks For Success.
If you’re new to growing cut flowers, here are three of my favorites things that should be in your kit:
My Top 3 Cut Flower Supplies
Floret Farm’s Cut Flower Garden: Grow, Harvest, and Arrange Stunning Seasonal Blooms: This is the book that inspired me to start growing cut flowers. Plant profiles, seasonal tasks, and arrangement tutorials will get anyone started with growing their own bouquets.
Fox Farm Fertilizer Soil Liquid Nutrient: Tiger Bloom: More flowers? Yes, please. I treat my cut flowers to a sip of this phosphorous-heavy liquid fertilizer throughout the season, so I never run out of fresh flowers in my house or garden.
Corona FS 3214D ComfortGEL Leaf & Stem Micro Snips: Perfect for cutting small stems, deadheading spent blooms, or keeping the mint plant from taking over my garden.
Find the rest of my “use on the daily” garden gear on my resources page.