Growing Sunflowers From Seed in Your Flower Garden

Anyone can grow sunflowers! Learn everything you need to know about growing sunflowers from seed in your flower garden. From choosing the right variety to watering and care, this guide makes sunflower success a breeze.

Sunflowers, with their bright, cheerful faces, are a welcome addition to any garden. They’re surprisingly easy to grow from seed, and their towering presence adds a touch of summer whimsy to your gardens.

Plus, sunflowers attract lots of beneficial pollinators like bees and butterflies, and their spent seeds are a favorite snack for humans and wildlife alike.

Learn how to seed sunflowers and grow them with these simple tips.

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Why Grow Sunflowers

Sunflowers are more than just happy faces in the garden! They bring a whole lot of sunshine to your space, both literally and figuratively. With their bright yellow blooms, they add cheer and variety, from towering giants to bushy plants with clusters of flowers.

But sunflowers are beneficial beyond their aesthetic. They attract butterflies, bees, and hummingbirds, helping your entire garden flourish with polinators. Later in the season, the seeds become a tasty snack for birds, making your garden a haven for wildlife.

Sunflowers are also surprisingly practical too. They’re easy to grow from seed, even for beginners, and many varieties reward you with blooms quickly.

And the best part? Certain types are perfect for cutting, letting you bring bursts of sunny blooms indoors too. And you can even enjoy the delicious and nutritious seeds they produce – a tasty reward for the work you put in growing them!

Choosing Sunflower Seeds

The first step to sunflowery success is choosing the right seeds. Sunflowers come in a variety of shapes and sizes. There are the classic giants with single, massive blooms, branching varieties with clusters of smaller flowers, and even dwarf sunflowers perfect for containers.

Consider the available space in your garden and the look you’re going for when making your selection. While I usually order my seeds online from Johnny’s Selected Seeds, you can easily find them at your local nursery, big box store, or online retailer.

Sunflower Varieties to Grow

• Giant Sunflowers: Certain annual sunflower varieties, notably Mammoth and Russian Giant, can easily surpass 10 feet, reaching heights of 15 feet or more. These towering beauties create dramatic focal points in any garden. I love to grow Mammoth in my gardens.
• Mid-Height Sunflowers: For those seeking a less imposing sunflower, varieties like Autumn Beauty and Lemon Queen offer a happy medium, typically growing between 5 and 8 feet tall.
• Compact Sunflowers: Don’t have the space for a towering sunflower? Dwarf varieties, including Teddy Bear and Sunspot, still offer those iconic blooms but at a more manageable 2-4 feet tall.
• Perennial sunflowers: Unlike annual sunflowers, perennial varieties come back year after year, adding consistent height to your garden borders. Expect them to reach 3-8 feet tall, depending on the specific variety.

Preparing Your Planting Area

Sunflowers thrive in sunny locations with well-draining, fertile soil. They need about 6-8 hours of full sun to get the most out of the flowers. Ideally, you’ll want to plant your seeds outdoors after the last frost has passed for your area. This ensures warm soil temperatures for optimal germination. Sunflowers do not do well starting them indoors, so directly sowing them outdoors is the best method.

Optimal Soil for Sunflowers

To give your plants the best chance to flourish, it’s crucial to know what they’re working with underground. A simple soil test can unlock the secrets of your soil’s composition and pH level, revealing which nutrients are abundant or lacking.

You can easily get this valuable information by picking up a soil test kit at your local garden center or sending a sample to a nearby cooperative extension service for professional analysis.

If you choose the DIY route, carefully follow the kit’s instructions to collect and analyze your soil. Alternatively, if you’ve sent a sample to a lab, simply wait for their detailed report.

Armed with these results, you can make informed decisions about amending your soil. Adding the right fertilizers or compost can adjust pH levels and replenish missing nutrients, creating the ideal environment for your plants to grow and thrive.

Sunflowers flourish in soil that’s both rich in nutrients and drains well. Ideally, the soil’s pH should fall within a range of 6.0 to 7.5.

It’s a good idea to loosen the soil to a depth of about inches with a garden fork. Then amend the area with compost and other organic matter to add nutrients and help with drainage. Speaking of drainage, you’ll want to grow them in a location that is well-draining and does not hold too much moisture.

Pro-Tip: To check your drainage, dig a hole 6″ deep, add water and watch how quickly it drains.

If your garden is freshly mulched like mine usually is when I start seeding sunflowers, you can also start them in small pots. I like to use peat pots filled with potting soil because they can be directly planted in the ground without disturbing the root system. By using some sort of small container in this way, you’ll have more control over the soil without having to disturb your newly mulched gardens.

Planting Sunflower Seeds

Planting sunflower seeds is a breeze and doesn’t take long to do. Unless of course, you are growing as many as me! LOL. Here’s how to do it:

• Planting Depth: Dig a hole 1/2 inch to 1 inch deep for each seed.
• Spacing: Space the holes according to the variety you’re planting. Giant sunflowers may need 3-4 feet between plants, while dwarf varieties can be spaced as close as 1 foot apart.
• Planting Technique: Place a single seed in each hole and cover it with soil. Water the planting area gently but thoroughly. Do not plant them closely together. You’ll waste the seeds needing to thin them out later.
• Succession Planting: Since most sunflowers are one-and-done type flowers, sow seeds about a week apart for several weeks so you can get a season of blooms. I don’t do succession planting because I grow so many different types of flowers, I just plant them once and they bloom when they flower.

Sunflower Care

Sunflowers are relatively low-maintenance plants. Here’s what they need to thrive.

• Watering: Water your sunflowers regularly at the base of plants in the earlier part fo the day. Keep the soil consistently moist for newly planted sunflower seeds and seedlings – they need it. Established, blooming sunflowers generally need deep watering (1 inch) once a week, but may require more (2 inches) during hot or dry periods. Adjust watering based on rainfall and soil type.
• Mulching: Mulching around the base of yoru sunflowers to help retain soil moisture, keep the roots cool and control weeds.
• Weeding: Keep the planting area weed free to prevent competition for water and nutrients.
• Fertilizing: Feed sunflowers a balanced NPK (nitrogen-phosphorus-potassium) fertilizer, like a 10-10-10 or 5-5-5, at planting and before flowering. Use slow-release granules or diluted liquid fertilizer every 2-4 weeks during the growing season. In my gardens, I use slow release granules so it’s set and forget.
• Staking (Optional): Tall sunflower varieties may benefit from staking to provide support, especially if they’re growing in windy areas. But be careful when you do this, because taller sunflowers can snap if they are tied to a shorter stake too tightly. This happened to me once several years ago and I’ve not staked my sunflowers since.
• Deadheading: Deadheading, or removing spent flowers, is a simple technique to promote continuous blooming in sunflowers. This helps the most when growing “one and done” varieties. But it’s also a great way to clean up your sunflowers if you don’t intend to harvest the seeds. This practice not only encourages the plant to produce more flowers but also helps maintain a neat and tidy appearance in your garden.

Staking Your Sunflowers

Staking sunflowers while they’re young will prevent them from toppling in rough weather. Use sturdy supports like bamboo stakes, trellises, or canes at least 6 feet tall, positioned 6 inches from the base. As the sunflower grows, loosely tie it to the stake with soft garden twine every 12 inches. For larger varieties, use multiple stakes or create a support frame.

Preventing Pest and Disease Problems With Sunflowers

While sunflowers are generally quite resilient, they can fall prey to pests and diseases. Here’s what to watch out for:

Common Sunflower Pests

• Sunflower Beetles: These small, black beetles can munch on leaves and stems. Handpicking and insecticidal soap are effective controls.
• Sunflower Moths: The larvae of these moths can bore into the sunflower heads and damage seeds. Early detection and treatment with Bacillus thuringiensis (Bt) can help.
• Aphids: These tiny, sap-sucking insects can weaken plants. A strong spray of water or insecticidal soap can usually dislodge them.

Sunflower Disease Problems

• Powdery Mildew: This fungal disease appears as a white powdery coating on leaves. Ensure good air circulation, avoid overhead watering, and consider using a fungicide if necessary.
• Verticillium Wilt: This soil-borne fungus causes wilting and yellowing of leaves. Choose resistant varieties and practice crop rotation.
• Sclerotinia (White Mold): This fungus can cause stem rot and wilt. Avoid overhead watering and ensure proper spacing for air circulation.

Prevention is Key

The best defense against pests and diseases is a healthy plant. Ensure proper spacing, adequate watering, and well-draining soil. Regularly inspect your plants for signs of trouble and take prompt action if you notice any issues.

Protecting Sunflower Seedlings and Flowers From Wildlife

I cannot tell you how many seedlings I’ve lost to rabbits, chipmunks, and other wildlife. Last year, I was so upset because I lost every single sunflower that I started from seed. And there were 60 of them! So it’s a really good idea to drop a cloche or some other protective covering over them while they are small. I just bought these cloches for this very purpose.

Sunflowers are not deer-resistant plants so make sure you plant them in a protected area and/or apply repellent often. I use this deer repellent that not only repels deer, but also rabbits, voles, and other wildlife. It is systemic and works incredibly well at keeping them at bay.

Enjoying Your Sunflowers

Sunflower seeds typically germinate within 7-10 days. Once they sprout, watch them grow quickly and bask in the beauty of their cheerful blooms. Sunflowers can start blooming anywhere from 6 to 10 weeks after planting, depending on the variety.

Growing Sunflowers in Pots

Don’t have a spacious garden? No problem! Sunflowers can thrive in pots, bringing their cheerful presence to balconies, patios, and decks.

• Choosing the Right Variety: For container gardening, opt for dwarf or semi-dwarf sunflower varieties. These compact cultivars, like Teddy Bear, Sunspot, or Sundance Kid, are bred to stay smaller and won’t overwhelm your pot or your space.
• Selecting the Right Pot: Choose a pot that’s at least 12 inches deep and wide to accommodate the sunflower’s root system. Make sure it has drainage holes to prevent waterlogging.
• Using the Right Soil: Fill your pot with a well-draining potting mix rich in organic matter. Sunflowers are heavy feeders, so a nutrient-rich soil will help them thrive.
• Planting and Care: Plant sunflower seeds 1 inch deep and follow the same spacing guidelines as for in-ground planting. Keep the soil consistently moist but not waterlogged. Place the pot in a sunny location, receiving at least 6-8 hours of direct sunlight per day.
• Staking: Taller sunflower varieties grown in pots may need staking for support. Use a sturdy stake or trellis and gently tie the stem to it as the plant grows.
• Fertilizing: Feed your potted sunflowers with a balanced liquid fertilizer every 2-4 weeks during the growing season.
• Watering: Potted sunflowers tend to dry out faster than those planted in the ground. Water them regularly, especially during hot weather, to keep the soil consistently moist.

By following these tips, you can enjoy the beauty and joy of sunflowers even in limited space!

Growing Sunflowers in Your Cut Flower Garden

Sunflowers are a great choice for adding sunshine and beauty to your cut flower garden. They are easy to grow from seed, with many varieties specifically bred to use as cut flowers. To extend your sunflower bounty throughout the summer, stagger your plantings by sowing seeds every few weeks throughout spring and early summer.

When planting sunflowers for cutting, keep in mind that they need more space than ornamental sunflowers in your garden. This improved air circulation and extra room allows the stems to grow stronger and support the flower heads better. Look for varieties like ‘ProCut’ series, ‘Sunbright™ Lemon Bicolor’, or ‘Triple Branching’ – these are specifically bred for cut flower gardens.

The ideal time to harvest your sunflowers for a bouquet is when the first few petals around the head begin to unfurl. Use sharp pruners or shears to make a diagonal cut on the stem. For additional success, consider staking taller sunflower varieties, especially in windy areas.

Regularly removing spent blooms (deadheading) encourages your sunflower plants to keep producing more blooms throughout the season. With a little planning and these tips, you can enjoy a continuous harvest of sunflowers to brighten up your cut flower garden all summer long.

Harvesting Sunflowers for a Radiant Indoor Display

Level up your living spaces with the sunlit charm of freshly cut sunflowers. These simple steps will ensure your blooms stay vibrant and long-lasting:

• Timing is Key: For optimal results, harvest sunflowers during the cool hours of early morning or late evening. This is when plants are fully hydrated, minimizing stress and promoting longevity in the vase.
• Selecting Prime Specimens: Choose stems with flowers that are just beginning to open or are fully open but still retain a firm texture. Avoid those that have started to wilt or drop petals. Don’t cut from flowers that are one-and-done bloomers unless you are okay with that being it for that particular sunflower.
• Clean and Precise Cuts: Use clean, sharp shears or a knife to sever the stems at a 45-degree angle. This angle maximizes water uptake, ensuring your sunflowers remain hydrated. Aim for a stem length of 12-18 inches to create visually appealing arrangements.
• Immediate Hydration: Plunge the freshly cut stems into a bucket of clean water immediately. This step is crucial to prevent air bubbles from entering the stems and impeding water uptake.
• Vase Preparation: Before transferring your sunflowers to a vase, remove any leaves that would fall below the waterline. Submerged foliage can promote bacterial growth and shorten the lifespan of your arrangement. And we want the longest bloom time possible!
• Maximizing Vase Life: For prolonged enjoyment, fill your vase with fresh water and add a floral preservative. Replace the water every few days to maintain freshness and prevent bacterial buildup.

For more tips about prolonging the vase life of your flowers, check out this post: How to Keep Fresh Flowers Longer

Extending Your Sunflower Blooms

Given the short flowering period, there is a way to get prolonged blooms throughout the summer. This requires a strategic combination of variety selection, planting techniques, and ongoing care.

• Selecting the Right Varieties: Prioritize branching sunflower varieties such as Autumn Beauty, Lemon Queen, or Velvet Queen. These cultivars are genetically predisposed to produce multiple blooms over an extended period, unlike single-headed varieties that bloom once and then focus on seed production.
• Succession Planting: To orchestrate a continuous floral symphony, stagger your sunflower planting times. Begin sowing seeds in late spring and continue every 2-3 weeks until early summer. This phased approach ensures that new plants are always coming into bloom as older ones begin to fade.
• Deadheading: Regularly remove spent blooms to redirect the plant’s energy from seed production to new bud formation. This simple yet effective practice can significantly prolong the blooming period of branching sunflower varieties.
• Nutrient Management: Maintain soil fertility by fertilizing your sunflowers with a balanced fertilizer or compost every 4-6 weeks. Adequate nutrition is essential for vigorous growth and abundant flowering.
• Hydration: Sunflowers are thirsty plants, especially during hot and dry weather. Ensure consistent moisture by watering deeply and regularly, but avoid waterlogging, which can lead to root rot.
• Pest and Disease Management: Monitor your plants for signs of pest infestations or disease outbreaks. Early detection and prompt intervention using natural and organic methods can help prevent these issues from hindering blooming.

Harvesting Sunflowers Seeds: Step-By-Step Instructions

Harvesting sunflower seeds is crazy simple to do and you’ll be rewarded with free seeds, a tasty snack, and food for birds and other wildlife.

Here are step-by-step instructions for harvesting sunflower seeds:

• Using sharp pruners, cut about a foot off between the head with the stem. Wear garden gloves for this process because the stems can feel a little prickly.
• Collect the seed heads in a garden debris bag, wheelbarrow, or garden cart. It will be much easier for you!
• After collecting the sunflower heads, lay a garbage bag on the table to help contain the mess and grabbed one flower head to start harvesting. You can also do this directly over a bucket if you prefer.
• When harvesting sunflowers, scrape the seed head with your fingers and allow the seeds to fall onto the table. The dryer the flower head is, the easier the seeds will pop out.
• Collect sunflower seeds and temporarily hold them in a stock pot or bucket.
• Remove the debris by adding them to a colander and then rinse them off.
• Spread the seeds evenly on paper towels in a single thin layer so they can fully dry off before using or storing.

To learn more about harvesting and saving your seeds, read this post that shares how to harvest sunflower seeds.

Seeding Sunflowers FAQs

Should I soak sunflower seeds before planting?

No, it is not necessary to soak sunflower seeds before planting. They will germinate within a few days after sowing them.

While not necessary, soaking sunflower seeds for 12-24 hours before planting can help speed up germination and improve the overall germination rate. I’ve never done this though and don’t think you need to do it.

What is the best month to plant sunflowers?

Sunflowers thrive in warm weather and full sun, so the ideal planting time is after the last frost in your area, typically late spring or early summer. Soil temperatures should be consistently above 50°F (10°C) for optimal germination.

The best month to plant sunflowers is determined by your last frost date. In my zone 6b garden, it is April 27 this year, but it has been later in May in prior years. Always check your last frost date and use that as your guide for knowing when the best time is to plant sunflower seeds.

How long does it take for sunflowers to grow from seed?

In general, most sunflower varieties range from 70-100 days from seed to flower. To give you a frame of reference, I usually plant my sunflower seeds around Mother’s Day and start seeing them flower around the end of July.

How deep should I plant sunflower seeds?

Plant sunflower seeds about 1 inch deep and 6 inches apart in well-draining soil. For larger varieties, space them further apart (12-18 inches).

Should I start sunflower seeds indoors or outdoors?

Sunflowers are best sown directly into the ground outdoors. They have long taproots and don’t transplant well. Also, they germinate with ease outdoors, so why waste the indoor growing space?

How long does it take for sunflower seeds to germinate?

Sunflower seeds usually germinate within 7-10 days in warm soil. But I’ve found them to germinate much faster in my gardens.

How often should I water sunflower seeds and seedlings?

Keep the soil consistently moist but not waterlogged is a common line you’ll hear, but what does it even mean? It means you don’t want your seedlings to dry out – they need that moisture to grow. However, if the soil is retaining moisture, don’t overdo it either. Water daily or every other day, depending on the weather and soil conditions. This will look different in every garden based on your climate and soil conditions.

Do sunflowers need fertilizer?

Sunflowers are heavy feeders and benefit from a balanced fertilizer, like a 10-10-10 or 5-5-5 formula. Apply fertilizer at planting with a slow-release fertilizer so they are consistently fed throughout their growth. You can also hit them with a bloom booster just before they flower.

When can I expect my sunflowers to bloom?

Depending on the variety, sunflowers typically bloom 70-120 days after planting.

Conclusion

Planting sunflowers from seed is a fun, rewarding plant to grow for gardeners of all skill levels. With a little planning and care, you can enjoy these cheerful blooms throughout the summer season.

Sunflowers, with their iconic golden faces, are a stunning addition to any landscape as they not only attract beneficial pollinators like bees and butterflies but also make incredible additions to bouquets.

I hope you found this comprehensive guide helpful, giving you the knowledge and tools needed to cultivate a thriving sunflower garden from seed to flower. Whether you envision a vibrant sea of sunflowers gracing your garden, desire to harvest their nutritious seeds, or simply wish to revel in their cheerful presence, this guide has you covered. With the expert advice and techniques presented here, you’ll be well on your way to cultivating a flourishing sunflower garden that radiates warmth and beauty throughout the growing season.

Share your sunflower success stories or ask me some questions in the comments below. And spread the sunshine by sharing this valuable resource with fellow gardeners who might find these tips beneficial.

To read more about sunflowers and how you can enjoy them, check out these posts:

• Harvesting Sunflower Seeds
• Front Door Sunflower Wreath for Fall
• Sunflower Brunch Table Setting Idea

To learn more about growing sunflowers from seed, read this post from the University of Georgia Cooperative Extension.

Happy Gardening!