How Long Does It Take to Grow a Sunflower from Seed

This post is all about how long does it take to grow a sunflower.

Sunflowers (Helianthus annuus) are among the easiest flowers to grow, making them a popular choice for home gardeners. This is one of my favorite flowers and I love to grow them. What’s not to love about sunflowers? They just look so happy! These iconic flowers are well-loved for their vibrant yellow petals and ability to brighten up flower gardens and landscapes. Whether you’re growing sunflowers for cut flowers, bird seed, human consumption, or simply to enjoy their beautiful flowers, understanding the sunflower growth stages will help ensure best results.

So, how long does it take to grow a sunflower from seed? The answer depends on the variety of sunflower, environmental factors, and cultural practices, but in general, sunflowers take between 70 to 100 days to reach full bloom from the time you sow seed. Some sunflower varieties get so big. I love growing grey striped mammoth sunflowers which take at least 95 days to mature and grow 8 to 12 feet tall!

This post is all about how long does it take to grow a sunflower.

Table of Contents

How Long Does It Take to Grow a Sunflower? Understanding Sunflower Growth Stages

Sunflowers are just so happy and cheery. They love the sun and follow it across the sky. Sunflowers follow a predictable growth cycle, from seed germination to maturity.

Here’s a breakdown of the key stages:

Germination (5-10 Days)

Sunflower seeds begin their journey by germinating in well-drained soil under warm temperatures. The ideal soil temperature for germination is 70-85°F (21-29°C). Since I don’t always have good luck with sunflower seeds with direct sowing (because of animals), I usually start them in little biodegradeable peat cups. Sunflowers don’t like their roots disturbed so this is the perfect way to transplant them without doing that.

Best time to plant: After the last frost when the danger of frost has passed.
Soil quality: Use fertile soil rich in organic matter for best results. Every year I use Black Kow to revitalize my soil and grow cover crops as well. Black Kow has been a huge help to our soil and totally brought it back from being completed depleted and terrible when we first moved to our property.
Planting depth: Sow seeds 1-2 inches deep and thin seedlings once they sprout.
Fertilization: Apply a light amount of fertilizer for larger flowers. Before applying any type of fertilizer, do a soil test first.

Consider doing succession planting to get blooms at different times! This is something I would really like to do this year since I tend to plant my sunflowers all at once.

Seedling Stage (10-20 Days)

As sunflower seedlings emerge, they develop young sunflowers with their first set of true leaves just like other plants do. During this stage, they need full sun is required for proper growth. Keep soil consistently moist but avoid overwatering. Overwatering can cause root rot and all kinds of other issues. Protect the seedlings from pests like japanese beetles and birds using pest control methods such as owl decoys. Birds and other pests haven’t really been an issue for me in the past once my sunflowers have gotten to the seedling state. It’s always been birds eating the seeds I’ve planted, which is such a bummer.

Vegetative Growth (20-60 Days)

Sunflowers experience rapid growth, producing tall stalks and strong main stems with an extensive root system. Some giant sunflowers can grow up to 12 feet tall during this period.

Best soil: Sandy loam or clay loam with good drainage.
Weed control: Keep the area weed-free to avoid competition for nutrients.

Budding and Flowering (60-90 Days)

By early summer or late summer, sunflower heads begin to form. Annual sunflowers produce a single bloom per stem, while dwarf sunflowers and perennial sunflowers may have multiple smaller blooms. Teddy Bear Dwarf sunflowers are the perfect example. They get one huge bloom and then have smaller shoots with blooms. They’re another favorite variety to plant just for this reason.

Sunflower varieties like American Giant or Mexican sunflowers may take longer to reach full potential. Practices like succession plantings ensure continuous blooms throughout the growing season.

Maturity and Harvest (90-100 Days)

At full bloom, sunflowers display their bright yellow petals and begin producing seed heads. Succession planting is a great idea because it never seems like the blooms last long enough. Once the flower starts producing seeds, they become very heavy from the weight. There are hundreds of seeds that are produced from just one flower. It’s an excellent opportunity to save those seeds!

Cut flowers: Harvest when petals begin to droop slightly.
Seed heads for consumption: Wait until the back of the seed head turns brown before harvesting for sunflower oil, bird seed, or to seed save.
Replanting: Allow some sunflower seeds to drop for the following year. I haven’t had much success with this. Usually the birds eat all of the seeds so I never have any flowers for the next year. I always have to plant each year.

how long does it take to grow a sunflower

Factors Affecting Sunflower Growth

When to Plant Sunflowers: Temperature and Climate

Sunflowers thrive in warm-season annuals conditions with a temperature range of 70-85°F. I’d say that they do pretty well with hotter temperatures and never really had any issues with them above those temperature. However, that temperature range is ideal for them. Late spring is the best time to plant sunflowers. I plant my sunflowers at the same time I start putting out my seedlings

Soil Conditions

For best soil conditions, conduct a soil test before planting. You’ll never know what’s lacking in your soil until you do a test. The last thing you want to do is to find out it’s lacking something when your crop(s) start to suffer. Sunflowers thrive in soil that ranges between slightly acidic to neutral (6.0 to 7.5 pH). Avoid high pH levels that limit nutrient availability. Ranges that are either too high or too low can really hamper your flowers and cause all kinds of issues.

Sunlight Requirements

Sunflowers need much sunlight—at least 6-8 hours per day—to reach their full potential. They love sun! You’ll find that most flowers do. Plant them in a sunny spot. I haven’t found that they’ve need any reprieve from the sun throughout the day like other plants might need.

Pest and Disease Management

As with any plant, there are some pests and diseases that can plague your crop. However, I haven’t really run into many issues with either of these. This is great because then I can focus on taking care of the plants that are more suceptible.

Common problem: Powdery mildew, downy mildew, fusarium wilt, verticillium wilt.
Use resistant sunflower varieties for disease resistance.
Implement weed control and space plants properly to improve air circulation. Look out for pests like weevils and cutworms which seem to be the notorious with my flowers. However, they can also be affected by aphids, sunflower beetles, and mealy bugs – just to name a few.

Plan Ahead of Planting

Before you start planting sunflowers, plan out your garden just as you’d normally do. Luckily, they get along with a lot of different plants as companions. Consider planting them with squash, corn, basil, cucumbers, peppers, beans, onions, and garlic (to name a few). They’re sturdy for meandering vines as a natural support system, and they provide shade for other plants that may need a break from the sun.

Remember that sunflowers can have huge leaves and have big flower heads so it’s important to keep this in mind.

Different Types of Sunflowers to Grow

What are some sunflowers that can be grown in your backyard garden? I’ve put together a list of ones to grow. Sunflowers are a great addition to your garden because they’re actually native to the United States, if you’re reading this in the US. So if you’re looking to add native plants, they’re definitely flowers to add to the list. You may be familiar with confection sunflowers. These are very commonly used for snacking/eating and great for roasting and salting, while their alternative are oil producing sunflowers. Confection sunflowers have larger and plumper seeds than ones that are used for making sunflower oil.

American Giant Sunflowers

This is one of the biggest sunflowers out there. We’re talking big! Huge! It grows up to 16 feet tall and has blooms that are 10 inches wide. This sunflower has an extremely sturdy stem, which makes sense because it’s a huge plant, and has enormous leaves. It definitely needs a lot of space in order to grow to its fullest potential. These big bad boys definitely don’t need to be staked unlike other tall flowers. They’re extremely sturdy even in high winds.

Chianti Sunflowers

I’d never heard of these types of sunflowers until I started diving in to learn all about sunflowers. The name makes sense though. They have wine-red velvety sunflowers that have blooms that are 3 to 4 inches wide, and they grow 4 to 5 feet tall. This may be a more practical sunflower to plant for those that don’t have a large enough space for the bigger varieties. It grow multiple branches, is pollenless, and great for a cut flower garden option.

Firecracker Sunflowers

This is a bicolor bloom that ranges from yellow on the outside of the petals to red on towards the center of the flower. They’re a great option for container planting because they’re on the smaller side – they get to a height of 4 to 6 feet and are considered a semi-dwarf. It can grow up to 10 flowers at a time. Since each flower has its own stem, it’s perfect as a cut flower option and is a pollenless variety.

cut flower garden — Firecracker sunflower

Grey Striped Mammoth Sunflowers

Grey Striped Mammoth sunflowers are one of my favorite sunflowers to grow because they’re just SO big. They grow up to 8 to 12 feet tall and have blooms that are 12 inches in diameter. These large heads that they produce are perfect for roasting and snacking on. They’re loved by bees, butterflies, AND hummingbirds. Each year I grow these flowers, they are absolutely loaded with honey bees. So they’re definitely something I try to grow each year since the bees really need them. In addition, they have really large leaves. Be prepared to give them lots of space because they’re 1 to 2 feet wide besides being tall.

Italian White Sunflowers

These would be a stunning addition to any garden and they’re not a very large variety so they don’t need a ton of space. They have a really beautiful pale yellow to almost white flower. This variety grow multiple branches and thus has multiple blooms. They grow up to 4 feet tall and have smaller flowers that are 3 to 4 inches wide. So this is another great option for a cut flower garden and can be used in bouquets.

cut flowers to grow — Italian white sunflower

Mammoth Sunflowers

This giant grows up to 12 feet tall and produces one big bloom which is 10 to 12 inches wide. These sunflowers produce large, bright yellow blooms with thick stalks that make them sturdy in the garden. They’re a favorite among gardeners for attracting pollinators like bees and butterflies. In addition to their beauty, mammoth sunflowers produce edible seeds that can be harvested and roasted. Their dramatic size also makes them a fun choice for kids’ gardens or as a natural privacy screen.

cut flower garden idea — Mammoth sunflower

Maximilian Wild Sunflowers

Maximilian wild sunflowers are tall, perennial plants that bloom in late summer and early fall with bright yellow flowers. Native to North America, they thrive in prairies (they’re actually a native prairie perennial), meadows, and along roadsides, attracting bees, butterflies, and birds. These sunflowers can grow up to 8 feet tall and spread easily, making them great for naturalizing landscapes. The flowers are 5 inches in width and the stalk get multiple blooms. Their drought tolerance and ability to grow in poor soil make them a hardy choice for low-maintenance gardens.

Mexican Sunflowers

I love growing these flowers and I’m pretty sure mine got way taller than the height that they say they grow. Mine were well over 6 feet tall. They get so many branches with so many blooms! Mexican sunflowers are vibrant, heat-loving plants known for their fiery orange or red daisy-like blooms. The blooms are on the smaller side and get to about 3 inches in diameter. Native to Mexico and Central America, they thrive in hot, sunny conditions and bloom abundantly from midsummer to fall. These fast-growing annuals can reach 4 to 6 feet tall and attract a wide range of pollinators, especially butterflies and bees. Their bold color and tall, bushy form make them a striking addition to flower beds or borders. Unfortunately, in the US, they’re annuals and don’t overwinter so they’ll have to be replanted each year.

Moulin Rouge Sunflowers

Moulin Rouge sunflowers are a unique variety known for their deep red to burgundy petals, offering a striking twist on the classic yellow sunflower. They typically grow to about 5 to 6 feet tall and produce multiple blooms per stem, making them ideal for cutting gardens. The blooms of Moulin Rouge sunflowers typically have a diameter of 4 to 6 inches. They’re a medium-sized flower compared to some of the giant sunflower varieties, but their rich, velvety red petals make them stand out beautifully in the garden or in bouquets.These sunflowers thrive in full sun and well-drained soil, blooming throughout the summer. Their rich color attracts pollinators and adds a dramatic flair to garden beds or floral arrangements. Moulin Rouge sunflowers are also pollen-free, making them a great choice for indoor displays.

Skyscraper Sunflowers

Skyscraper sunflowers are towering giants that can grow up to 12 feet tall or more, making them one of the tallest sunflower varieties. They produce large, classic yellow blooms that can reach up to 14 inches in diameter. These sunflowers thrive in full sun and rich, well-drained soil, often requiring support due to their impressive height. They’re excellent for creating a dramatic garden backdrop and are a favorite among pollinators. Skyscraper sunflowers also yield large seeds, perfect for snacking or feeding birds.

‘Snack Mix’ Sunflowers

Another popular variety is ‘Snack Mix’ sunflowers. ‘Snack Mix’ sunflowers are grown primarily for their large, plump seeds that are perfect for roasting and eating. These sunflowers typically reach 5 to 7 feet tall and produce broad flower heads packed with seed. The blooms typically measure 8 to 10 inches in diameter. These large flower heads are designed to produce an abundance of sizable seeds, making them ideal for snacking or bird feed. They thrive in full sun and well-drained soil, making them easy to grow in home gardens. In addition to being a great food source, the flowers also attract pollinators like bees. Once dried, the seed heads can also be used to feed birds in the fall and winter.

Strawberry Blonde Sunflowers

Strawberry Blonde sunflowers are a stunning variety known for their soft, rose-pink petals that fade into creamy yellow tips, creating a unique, multicolored effect. They typically grow to about 5 to 6 feet tall and produce multiple blooms on branching stems. These sunflowers bloom from mid to late summer and are ideal for both garden beds and floral arrangements. The blooms of Strawberry Blonde sunflowers typically measure 4 to 6 inches in diameter. Their medium-sized flowers, combined with the soft blend of pink, rose, and creamy yellow tones, make them a standout in gardens and bouquets. Their gentle color palette makes them a favorite for romantic or cottage-style gardens. Like many sunflowers, they also attract bees and butterflies, supporting pollinators.

Sunny Smile Sunflowers

Sunny Smile sunflowers are a dwarf variety that brings a cheerful burst of yellow to any garden. They typically grow to about 2 to 3 feet tall, making them perfect for small spaces, container gardening, or borders. These sunflowers produce bright, classic yellow blooms that are around 4 to 6 inches in diameter. Known for their compact size and vibrant color, they attract bees and butterflies, adding both beauty and pollinator support to the garden. Sunny Smile sunflowers are also great for cutting and bringing a touch of sunshine indoors.

Teddy Bear Dwarf Sunflowers

These are another one of my favorite flowers to grow! Teddy Bear dwarf sunflowers are a charming variety with soft, fluffy, double-petaled blooms that resemble a teddy bear’s fur. These compact sunflowers typically grow to about 2 to 3 feet tall, making them ideal for smaller gardens, containers, or as an accent plant in flower beds. Their golden yellow flowers, ranging from 4 to 6 inches in diameter, create a cheerful display that attracts bees and butterflies. Teddy Bear sunflowers are also prized for their ability to bloom in abundance, making them a great choice for cut flowers or adding a burst of color to any space. Their small size and unique look make them especially popular in children’s gardens.

How to Grow Sunflowers Faster

If you want to speed up sunflower growth, consider these tips:

Start seeds indoors in peat pots to get a head start.
Choose dwarf varieties or annual types with a shorter growing season.
Water with a gallon of water per plant every couple of weeks to encourage deep roots.

Conclusion

Growing sunflowers is rewarding and relatively easy, even for beginners. How long does it take to grow a sunflower? Depending on the type of sunflower, most sunflower plants take 70-100 days from seed to full bloom. With the right conditions—full sun, well-drained soil, and warm temperatures—you can enjoy these iconic flowers throughout the growing season. Whether you’re planting for vegetable gardens, ornamental plants, or sunflower oil, sunflowers are a good idea for any garden.

Now that you know how long it takes to grow a sunflower from seed, it’s time to sow seed and watch these beautiful flowers thrive in your garden!

What type of sunflowers would you like to grow or have grown? Leave a comment below!

This post was all about how long does it take to grow a sunflower.