How to Grow Sunflowers
There isn’t a garden out there that doesn’t look impressively more colorful and magical when these sun giants start to bloom.
Sunflowers, properly named Helianthus, nod to the way their petals look like the sun. The most recognized type of sunflower has bright yellow petals and tall stalks, but there are actually about 70 species in total.
Adding sunflowers to your garden is always a great choice since they brighten up any space and can be purchased in varying heights. Although they don’t get to share their beauty for very long, once you get to experience sunflowers in bloom, it’s worth it every year.
If you want to know how to grow sunflowers in your garden, the following information will be helpful. We’ll discuss the basic needs of the sunflower, how to cater to larger breeds, and what to do when you come face-to-face with sunflower garden pests. While they’re not the pickiest flowers in any garden, these gorgeous bloomers do have some preferences that you’ll want to know about before planting seeds.
The Sunflower
All except three species of the sunflower are native to North and Central America. The common sunflower refers to a species type of the Helianthus genus, called Helianthus annuus.
This species and a handful of others are grown in temperate regions, but can also be grown in tropical locations as well. They are a source of food for humans and livestock, but they’re also very popular as decorative plants in garden spaces. The common sunflower generally blooms in the summer and into fall, but sunflowers prefer the warm summers most of all.
Physical Aspects
Sunflowers have both annual and perennial plants, with some versions growing as tall as 10 feet or more! The tallest sunflower ever recorded stood at a height of 30 feet 1 inch, grown by a man named Hans-Peter Schiffer in Germany.
While the bright yellow petals are a vision to behold, one of the coolest things about the sunflower is its disk. The disk looks to be one piece but is actually made up of 1,000-2,000 tinier flowers inside.
Additionally, sunflowers have a very interesting behavior that is known as heliotropism. This refers to the way that the flowers will gradually tilt their heads throughout the day, allowing them to follow and face the sun. That being said, a field of sunflowers will face east in the morning and finish the day facing west.
When grown in the perfect conditions, sunflowers should have a hearty, thick stem, and heart-shaped leaves. One flower can hold as many as 2,000 seeds, one of which is for eating (the striped seeds), while the other is for making oil (the black seeds).
If you’re planting sunflowers in your garden, there’s a good chance you’ll have some extra furry friends stopping by to taste test left behind seeds.
Gardeners who choose to incorporate these flowers into their gardens do so for a variety of reasons, including visual interest, seed use, or to cut them for bouquets. Even birds love sunflower seeds and will happily eat the ones you share with them.
Types of Sunflowers
With so many sunflower varieties to choose from, you’ll definitely fall in love with at least a handful of breeds. Here are some popular varieties to consider implementing into your garden landscape:
Lemon Queen
This gorgeous sunflower is perfect if you want a breed that boasts the traditional yellow petals and deep-colored disk. The Lemon Queen has short, stout petals that are a vibrant yellow. The disk is quite large, which makes this version very popular with pollinators.
Moulin Rouge
Those gardeners who want some color variety in their sunflowers will love the Moulin Rouge breed. The petals on this flower are a rich, burgundy color that sometimes turns yellow right at the base. The disk is a chocolate brown color, and the plant only grows to be about four feet tall. Perfect for anyone who wants a more manageable height.
Little Becka
The Little Becka, suitably named, only grows to about three feet tall. Its petals are a thing of beauty, beginning with gold at the base, turning into deep burgundies, then back to bright gold on the tips.
Mammoth Russian
If you’re serious about growing large sunflowers, then a Mammoth Russian just might be in your future! This specific breed can grow anywhere from nine to twelve feet tall, and the rich yellow flowers are a welcome sign for pollinators. Take care to plant these seeds with enough room for all.
Planting Sunflower Seeds
Planting sunflower seeds can be a great project for gardeners of any age. It is best to wait until any signs of potential frost have passed, and the soil has a minimum temperature of 55-60 degrees Fahrenheit.
For cooler regions, this usually happens between mid-April to late-May. Warmer regions will naturally be ready sooner.
If you have a taller variety of sunflower seeds, it’s ideal to have a structure that protects them from windy conditions and potential damage. This could be a fence, a shed, or a house. The good news is sunflowers look amazing no matter where you place them.
If you’re working with a sunflower variety that is tall, you will need less space between seeds. However, low-growing options tend to grow horizontally and need more room as a result. With that in mind, rows of sunflowers should be at least 30 inches apart.
Begin by breaking up your soil with a spade and removing any existing rocks and weeds. A thick layer of compost should be mixed into this area, which will improve drainage and nutrients. Add your fertilizer to the bed of soil as well before planting seeds.
We suggest planting each seed at least one inch into the soil and ensuring that they are no less than six inches apart. If you notice that you have birds going after your planted seeds, think about adding some netting over the area until the seeds sprout.
Once your sunflowers have broken the soil and grown to be about six inches tall, you can then think about thinning them out. This is simply a process of getting rid of weaker, more frail flowers that are taking away nutrients from the stronger flowers.
Growing Sunflowers
Sunlight
Not surprisingly, sunflowers love to get as much sun as possible. Direct sunlight is preferred, with anywhere from six to eight hours of sunshine every day. If you want your flowers to do their best, it is best if you live somewhere you get long, hot summers.
Take a look into your garden and get to know where the sun hits for the longest. This is where your sunflowers should go.
Soil
The great thing about sunflowers is that they aren’t too demanding when it comes to the soil you use. That being said, they can tolerate anything from slightly acidic soil to alkaline soil. This measures a pH soil level between 6.0 and 7.5.
When you are preparing your soil for seeds, dig a circumference between two and three feet wide and two feet deep. When you do so, pay attention to the type of soil you have. It should be loose and well-draining so that the sunflower’s roots are able to become moist but not soggy.
Soil should be nutrient-rich; sunflowers can have an appetite, so they’ll want something delicious to snack on. Organic matter or compost will do well to feed your sunflowers. If you’re working with a soil that isn’t quite as nutrient-rich as you hoped for, you can always incorporate some granular fertilizer.
Fertilizer
Sunflowers don’t need to eat all summer long, so fertilizing isn’t necessary too often. Similar to other plants, too much fertilizer can mean a spike in nitrogen. This will result in lots of green foliage, but you will have fewer flowers to enjoy.
Light fertilizing with the right makeup will be very beneficial to your sunflower garden. Sunflowers like a fertilizer that is low in nitrogen, so a blend of 5-10-10 should suffice. For this type of flower, you’ll want to use the lowest suggested amount.
Once you’ve fertilized the first time, you likely won’t need to do it again for the rest of the growing season. If you’ve got a perennial type of sunflower, annual fertilization is necessary. Continue with a low-nitrogen fertilizer; water the soil about six inches away from the plant, and give it a good soak.
This will ensure that the nutrients fully soak into the soil without burning the actual plant.
Watering
When your sunflowers are just small sprouts, they’ll need a good amount of water to grow strong. You’ll need to water around the root area, staying a few inches away from the actual plant.
Once you’ve got an established sunflower, take care to water your plant deeply but not too often. A good watering once a week will suffice to keep the soil moist. If your region experiences droughts through the summer, take care to water the soil more often.
Sunflower Pest Prevention
Sunflowers aren’t known for being the favorite snack of garden pests, but that doesn’t mean that you won’t have to deal with them from time to time. Some of the most common pests that might munch on your sunflowers include sunflower beetles, cutworms, midges, and maggots.
You’ll be able to tell right away if your gorgeous sunflowers are struggling with pests. In most cases, there will be evidence of chewing either on the petals, leaves, or disk.
If you’re on top of the problem, you might be able to rid the flower of the pests by hand. They can usually be found underneath the leaves, where you can flick them off and drop them into some soapy water.
If you’ve got garden animals that are chewing on them, having chicken wire placed around the flowers can be beneficial as well.
Sunflower Beetle
The Sunflower Beetle is exclusive to the sunflower, and it is a defoliator. It can do extensive damage to your flowers, but mature sunflowers can often survive these attacks. These beetles can create large holes in the leaves, empty kernels of their seeds, and even reduce the oil content of the flower.
Applying an organic insecticide should help deter these pests.
Cutworms
Cutworms are more damaging to the sunflower, causing havoc above and below the surface. They will bite into stems and leaves and suck the sunflower dry. You’ll notice your sunflowers begin to wilt, and you might also see the presence of notches take out of the leaves.
To get rid of cutworms, stir up the soil around the plant twice a day; cutworms are dormant during the day and will be nearby. Similarly, you can check for cutworms at nighttime while they are actively eating. Insecticide can also help to kill these pests.
Harvesting Sunflowers
If you’ve been growing your sunflowers for the ultimate bouquet, you’ll want to pay attention to the perfect time for harvesting. Cutting your sunflowers should happen in the morning since this will prevent the flowers from wilting too fast.
Take note of when the flower buds are just about to open, and then cut the stem. This can help to increase the number of side blooms.
Water in your vase should be room temperature, which will allow the sunflowers to stay in bloom for about a week.
Harvesting Sunflower Seeds
Once your sunflowers have given you all they can visually, you’ll want to take advantage of the seeds that come after! These seeds can be used for human snacks, food for animals, or to re-grow more sunflowers next season.
As the summer comes to an end, wait for the back of the sunflower’s head to turn brown. You should be able to recognize the seeds right away, as they will be plump and ready for picking.
Using a pair of pruners, slice off the head of the sunflower about six inches down the stem. Prepare to collect the seeds with a bowl, and begin rubbing your hand over the seeded area. Alternatively, you can also use a fork.
Rinse the seeds and lay them out to dry overnight. If you’re going to be using them for re-planting, store them in an air-tight container. Keep them in a dark, cool location.
If you’re trying to avoid the birds beating you to your snack, use a thin material to wrap around the head of the sunflower until the seeds are ready. Secure with a band around the stem.
Sunflower Hulls
Once your harvest of sunflower seeds has come and gone, you might be left with a whole lot of sunflower hulls. The first thing you need to know is that the hulls are not meant to go in the garbage – they have way too many other beneficial uses just to end up sitting at the dump.
One of the cool things about the sunflower is that it is able to practice allelopathy. This means that the sunflower has chemical compounds that discourage the growth of other plants around them. The chemicals are found in every part of the sunflower – including the hulls.
Some gardeners suggest that, instead of throwing out your hulls, you might compost them. However, others argue against this act and believe it negatively affects the end product of the compost.
To avoid hurting your quality compost, many gardeners instead suggest using hulls as a way to suppress the growth of weeds. You can scatter the hulls in areas where you don’t want weeds to grow, such as along pathways and amongst an established garden.
Tips for Growing the Largest Sunflowers
Gardeners who aspire to grow the largest sunflowers on their block will need to take a few things into consideration.
Stick with Yellow
Although there are all kinds of sunflower breeds out there today, it’s unlikely that you’ll be able to grow a giant sunflower in colors outside of the traditional ones. That being said, tall sunflowers almost always have the original yellow petals and dark brown centers. If you’re attracted to something crimson, orange, or otherwise, you’ll have to be okay with shorter heights.
The More Sun the Better
All sunflowers require six to eight hours of full sunlight; however, if you’re wanting to grow sunflowers that are larger than most, you’ll want to give them even more sun than that.
As a golden rule, the more sun the better. If you can locate a space that gets a full day of sun, you might want to relocate any existing plants and let your sunflowers have their chance there.
Focus on Soil
If you’re trying to grow large sunflowers, they’re going to require a lot of nutrients to feed from. Sunflowers tend to deplete the soil more than other flowers, especially when they’re trying to grow so large.
Replenish the soil around these sunflowers each season, and work in a granular fertilizer. You can feed your larger sunflowers consistently through the warmer seasons. Along with composted manure or organic fertilizer, you might also want to mix in additional minerals that can come from components such as dried seaweed.
Never Use Pots
If you want to grow the largest sunflowers possible, it is important never to start your seeds in pots. This is because the roots of the sunflower begin to grow very quickly, and any confinement will stunt their growth right from the get-go.
Avoid stunting root growth or holding off on transplanting and instead put your seeds right into the ground where they can grab hold and grow.
Additionally, it’s important to plant your seeds as soon as you can after signs of the last frost. Planting mid-summer usually means larger flower heads but shorter stalks, which is not what you want.
Mind Your Spacing
Giant sunflowers like to be about 20 inches apart. Planting them any closer can result in very tall stalks; however, they’ll have very small heads that look disproportionate to their height.
Plant them any further apart and the stalks may be too weak to hold up their larger heads. For best results, you might consider planting seeds in small clumps and thinning out later.
Mind Your Flowers
You’ll need to be attentive to your high-reaching flowers since they are more exposed to the elements and may need extra help. Keep an eye on the weather; if heavy winds are in the forecast, you’ll want to pause on watering so the stalks are so soft and prone to bending.
Staking can help with your giant sunflowers, but it usually isn’t necessary if your flowers have been raised properly. Their thick stalks should keep them upright, but if you’re working with sunflowers in a small space, staking might be an option.
Becoming a Sunflower Guru
If you want to know how to grow sunflowers in your garden, you’ll be pleased to know that it’s all about experimenting. Not every type of sunflower will do well in your space, but there’s a good chance that you’ll find a handful that will flourish all season!
Keep in mind their preferences to sunlight, water, and soil, and you’ll be well on your way to building a sunflower garden that will impress your visitors year-after-year. Of course, be sure to learn about the kind of soil you have before you think about planting sunflower seeds; this will help to ensure that you can provide the basic necessities that sunflowers require to grow tall and beautiful.
