One of my favorite summer memories comes from the summer of 2012, when I spent six weeks studying Spanish in Spain with my sister. The school regularly took us on trips to popular and historically significant towns and regions in the country.
On one trip to Barcelona from Valencia, we drove past fields of sunflowers.
Photo by Laura Melchor.
In this guide, we’ll tell you everything you need to know to grow your own joy-inducing Helianthus annuus flowers.
Here’s what’s ahead:
Cultivation and History
Sunflowers are as delicious to eat as they are joyful to look at.
Lots of people love snacking on the seeds. Personally, I love sun butter as a substitute for peanut butter. And the oil from these giant beauties is used in cooking all over the world.
member of the Asteraceae or daisy family, along with marigolds, asters, and the humble dandelion, to name a few.
produce half the world’s supply, with Argentina, Turkey, France, Hungary, Spain, and China growing most of the remainder of what’s sold commercially.
Despite its global renown, the sunflower originated in North America and was a major food crop for many indigenous peoples. Today, it’s mainly grown on farms in North and South Dakota, Minnesota, California, Colorado, Kansas, Nebraska, and Texas.
If you’re a beginning gardener or you want a fun gardening project for your kids to do, growing is the way to go.
These flowers are super easy to grow, and they aren’t picky about their growing conditions. You can propagate them from seed or transplant seedlings from the store.
Growing from Seed
Like other plants with taproots, sunflowers grow best when sowed directly into the yard or garden. This gives them plenty of space and time to develop the taproots and send them down deep.
We’ll focus on that method first.
flowers are annuals, so you can grow them just about anywhere, but they don’t like to get too cold.
They prefer USDA Hardiness Zones 2-11, and they definitely want you to wait to plant them outdoors until all danger of frost has passed.
Photo by Laura Melchor.
And my tiny ones, which still looked lovely in a vase indoors, looked like this:
So keep this in mind while planting! Some plants will overshadow others, but the smaller ones will be ideal for bouquets.
Once you’ve set the seeds in the trench, cover them with an inch of soil and water thoroughly. Keep moist until germination, which should occur in 7-10 days.
As soon as the first set of true leaves emerges, thin any stray seedlings that are too close together – those that are growing more closely than two inches from their neighbors.
Also, did you know that sunflower sprouts are edible? So instead of tossing the extra seedlings in the trash, toss them into a salad.
That’s all there is to it! You’ll see flowers in anywhere from two to three months, depending on the variety.
sow seeds indoors before the danger of frost passes, you do it.
You’ll want to start just a few weeks before the last frost date so that the plants don’t get too big in the seed trays.
If they grow too large while the roots are still trapped in a small cell, they may not thrive once they’re moved outdoors.
Sow two seeds each, one inch deep, in starter trays or peat pots. Keep them moist.
Thin seedlings once they have a set of true leaves, keeping the strongest one in each pot or cell, and transplant them out after all danger of frost has passed, or when seedlings are about three to four inches tall.
Harden them off for about a week before planting out in the garden.
If you find seedlings at the store or have grown your own in starter trays, here’s how to transplant them outdoors.
Check the seed packet to make sure, and keep in mind that branching varieties need more space than single-stemmed types.
How to Grow
Sunflowers can handle high temperatures, as they love warmth, but they hate freezing temperatures and don’t like frost.
Here’s a secret: they can handle a bit of frost, so if a surprise light frost hits later in the season than usual, they’ll probably be okay.
depending on how much rain you get.
To check the soil for moisture, stick your finger one inch down. If you don’t feel anything wet, give your plants a good inch of water each.
If wind is a problem as the flowers grow taller, you can stake them. A good trick is to plant sunflowers close to a fence, which can be used for support.
balanced 5-5-5 (NPK) fertilizer, which you’ll only need to use once. Add it to the planting area according to package instructions when seedlings have several sets of true leaves.
- Plant after the last frost
- Keep seeds moist until germination
- Plant in an area with full sun (at least 6-8 hours of direct sunlight)
- Fertilize lightly with a balanced 5-5-5 NPK fertilizer
Cultivars to Select
Here’s a nice, varied selection of sunflowers, both tall and small(ish), to grow in your home garden:
Want an enormous bloom to enter into a state fair competition? Look no further than ‘Mammoth Russian,’ which grows up to 144 inches tall and boasts a huge, twelve-inch, sunny heads.
‘Mammoth Russian’ also produces excellent seeds for snacking, with thin, easy-to-crack shells and meaty kernels.‘Mammoth Russian’
Flowers will bloom about two months after planting, with harvestable seeds available in another two to four weeks.
For an excellent supply of summer-long bouquets, succession-plant these beauties in your garden for four or five weeks in the spring.
Blooming in just over two months from sowing, you’ll have a near-constant supply of three-foot-tall plants with delicately cheerful blooms to gaze at in the garden, or cut and enjoy in vases and arrangements.
You’ll find seeds in a variety of package sizes, from a small packet to a five-pound sack at Eden Brothers.
You didn’t think sunflowers only came in shades of yellow and orange, did you?
Try mixing these three-foot-tall plants with one of the yellow varieties for a captivating show in your garden.
Seeds are available from True Leaf Market in packets ranging from two grams to one pound.
Managing Pests and Disease
There are a variety of maladies and creepy-crawlies to watch out for when you’re growing sunflowers.
Let’s take a look.
There are two main omnivore pests (or guests) that will happily eat your sunflowers, most notably once the seeds develop..
Read on to find out who they are!
Squirrels and Birds
These critters adore the seeds, with good reason. So do we, after all!
Photo by Frank Peairs, Colorado State University, Bugwood.org, via CC BY-SA.
Cutworms are moth larvae, and they eat the foliage, creating holes in young leaves, and making young plants wilt and sometimes die.
While they feed mostly at night, cutworms like to hang out during the day in the soil, or under weeds growing within a few feet of their chosen victim.
If you notice cutworm damage and find larvae nearby, it’s time to handpick as many as you can find and get rid of them.
These common bugs don’t do tons of damage to sunflower plants, but they do like to chew on the foliage and sometimes the seeds.
Department of Entomology at Kansas State University, they don’t tend to destroy entire plants. Commercial growers should plan to do something to deter grasshoppers if they notice more than eight per square yard.
Using a grasshopper deterrent that doesn’t harm other insects or the plant itself is ideal.
Try Nolo Bait, a coated bran flake that infects grasshoppers with , a pathogen that affects grasshoppers and crickets.
Nolo Bait is available from Arbico Organics.
To prevent an infestation, try planting squash, peas, or tomatoes in the same area as your sunflowers – grasshoppers tend to avoid these.
This 1/4- to 3/8-inch-long beetle () sports a reddish-brown head and a creamy, striped body.
The fat, greenish larvae and the adults both like to eat through the foliage, often skeletonizing entire plants.
If you catch these insects early and repel them with insecticidal soap or neem oil, there’s a good chance your sunflower crop will survive and thrive.
Sunflower Bud Moths
This moth’s cream-colored 3/8- to 5/8-inch larvae () do the damage here.
They like to bore into stems, and occasionally budding flowers. They tend to make themselves so at home within a plant that they leave lots of visible black frass, or excrement, behind.
If any of your sunflower stems or buds have curled inward and they sport a strange black substance around the damaged area, you probably have bud moth larvae on your hands.
Thankfully, if the larvae stay inside the stems, your buds will probably open just fine. But if they decide to attack the unopened buds as well, those flowers will be ruined.
Bud moth infestations are usually small and insecticides aren’t helpful.
To reduce the chance of an infestation, keep the surrounding area free of weeds, which can be host plants for the moths and their larvae.
Sunflower Headclipping Weevils
Think of these small black weevils () as little sunflower serial killers.
The female weevils chew through the stems of flowers just below the blooms, cutting most of the head off the plant.
But instead of finishing the decapitation, the females mate with male weevils inside the cuts they’ve made in the hanging flower heads, and then after the heads eventually fall to the ground, the eggs hatch.
Photo by Howard F. Schwartz, Wikimedia Commons, via CC BY-SA.
There’s no effective fungicide available for treating these diseases, so the best thing to do is practice crop rotation, select resistant cultivars, avoid overly damp conditions, and ensure adequate airflow between plants.
Rhizopus Head Rot
The first signs of this infection, caused by the fungi s, , and , are black spots on the backs of your sunflower heads.
Once these spots develop, it’s only a matter of time before the entire head shrivels and fills with spores can easily spread to surrounding plants in windy conditions.
While there are no effective control measures available, keeping sunflower head moth and bud moth populations under control can help to prevent the spread of this disease. The moth damage tends to make plants more susceptible to Rhizopus Head Rot.
Various types of fungal rust infections can plague sunflowers, including yellow rust (caused by ), white rust (caused by ), and red rust (caused by ).
Depending on the type of rust, these cause orange, yellow, or whitish spots to develop on leaves and sometimes even the stems.
Use a copper-based fungicide to treat rust, and try to avoid it in the first place by planting resistant cultivars, keeping leaves dry, and disinfecting all your gardening tools between each use and between plants to prevent spread.
Also known as Sclerotinia wilt, white mold is the most devastating sunflower disease out there.
Caused by a fungal pathogen, , the disease usually hits the roots first, making the sunflower wilt suddenly. And then – as though that wasn’t enough – a canker develops at the base of the plant and eventually takes over much of the stem.
There’s not much you can do once white mold hits your sunflower patch, except pull and destroy affected plants and hope that the disease doesn’t spread too much.
Next season, plant a non-host, such as corn or another grain, in the area and avoid giving sunflowers a home there again for four years.
Harvest the seeds after most of the flower petals have died and dropped off. Then, cut off the seed heads and about two inches of stem.
To save the seeds for planting next summer, store dried (not roasted) seeds in a brown paper bag. They’ll remain viable for up to seven years!
If you plan to eat most of your seeds, here are a few important points to remember:
- Raw, unshelled seeds can last in the pantry for 2-3 months, or in the fridge or freezer for up to one year
- Roasted, shelled seeds last for 3-4 months in the pantry, and up to a year in the fridge or freezer
- Roasted, unshelled seeds last for 4-5 months in the pantry, and for a year in the fridge or freezer
Recipes and Cooking Ideas
Sunflower seeds aren’t just good for snacks!
They make an incredible pesto, like you’ll find in this spinach and sunflower seed pesto grilled chicken recipe from our sister site, Foodal.
You can also use the seeds to make a healthier breading for fried chicken, as in this Foodal recipe.
Seriously, how delicious do those chicken fingers look?
The tasty seeds are filled with iron, protein, vitamin E, fiber, and zinc, so they’re nutritious any way you choose to enjoy them.