Planting, Growing, and Caring for Sunflowers
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Planting
First and foremost, find a sunny spot! Sunflowers grow best in locations with direct sunlight (6 to 8 hours per day); they require long, warm summers to flower well. Shelter from strong winds—for example, along a fence or near a building—helps as they mature. Larger varieties may become top-heavy, and a strong wind can topple them.
Choose a location with well-draining soil. The planting spot shouldn’t pool with water after it rains. Otherwise, sunflowers aren’t too picky about soil, but the soil shouldn’t be too compacted for the best results. They have long tap roots that need to stretch out; in preparing a bed, dig down or till 2 feet in depth and about 3 feet across. They’re not too fussy when it comes to soil pH, either. Sunflowers thrive in slightly acidic to somewhat alkaline soil (pH 6.0 to 7.5).
Sunflowers are heavy feeders, so the soil needs to be nutrient-rich with organic matter or composted (aged) manure. Or, work in a slow-release granular fertilizer 8 inches deep into your soil.
Plant sunflowers in a spot sheltered from strong winds, perhaps along a fence or building. Larger varieties may become top-heavy, and a strong wind can be devastating.
Before choosing a planting site, decide whether or not you want to grow a sunflower tower—a fun project for kids!
When to Plant Sunflowers
- It’s best to sow sunflower seeds directly into the garden (or outdoor containers) after the danger of spring frost has passed, anytime after soils have warmed to at least 50°F (10°C).
- In the northern half of the U.S. and in Canada, this will fall between April and mid-June. In the South, this will probably occur in mid-March or early April.
- Sunflowers dislike having their roots disturbed, so we recommend direct sowing instead of transplanting.
Planting Sunflower Seeds
- Sunflowers should be planted 1 to 1½ inches deep and about 6 inches apart after the soil has thoroughly warmed. If you wish, you can plant multiple seeds and thin them to the strongest contenders when the plants are six inches tall.
- Give plants plenty of room, especially for low-growing varieties that will branch out. Make rows about 30 inches apart. (For very small varieties, plant closer together.)
- A light application of fertilizer mixed in at planting time will encourage strong root growth to protect them from blowing over in the wind.
- Experiment with plantings staggered over 5 to 6 weeks to keep enjoying continuous blooms.
- If you see birds scratching around for the seeds, spread netting over the planted area until the seeds germinate. See more ways to keep birds away from your garden.
Check out this video to learn how to plant sunflowers:
Growing
- While the plant is small, water around the roots, about 3 to 4 inches from the plant. To protect the plant, it may help to put snail or slug bait around the stem.
- Once the plant is established, water deeply, though infrequently, to encourage deep rooting. Unless the weather is exceptionally wet or dry, water once a week with several gallons of water.
- Feed plants only sparingly; overfertilization can cause stems to break in the fall. You can add diluted fertilizer into the water, though avoid getting the fertilizer near the plant’s base; it may help to build a moat in a circle around the plant about 18 inches out.
- Tall species and cultivars require support. Bamboo stakes are a good choice for any plant that has a strong, single stem and needs support for a short period of time.
Harvesting
Cutting Sunflowers for Bouquets
- For indoor bouquets, cut the main stem just before its flower bud has a chance to open to encourage side blooms.
- Cut stems early in the morning. Harvesting flowers during the middle of the day may lead to flower wilting.
- Strip stems of all leaves except for those closest to the flower head. Recut bottoms of stems at a 45-degree angle.
- Handle sunflowers gently. The flowers should last at least a week in water at room temperature.
- Arrange sunflowers in tall containers that provide good support for their heavy heads, and change the water every day to keep them fresh.
Harvesting Sunflower Seeds
At the end of the season, harvest sunflower seeds for a tasty snack and or to replant or to feed the birds in the winter!
- Let the flower dry on or off the stem until the back of the head turns brown, the foliage turns yellow, the petals die down, and the seeds look plump and somewhat loose.
- With sharp scissors or pruners, cut the head off the plant (about 6 inches below the flower head). Place in a container to catch loose seeds.
- Lie the sunflower head on a flat, clean surface and grab a bowl to hold the seeds.
- To remove the seeds, rub your hand over the seeded area and pull them off the plant or you can use a fork. Another way to remove them is to rub the head of the sunflower across an old washboard or something similar. Just grip the head and rub it across the board as if you were washing clothes.
- If you are going to harvest the seeds for roasting, you can cover the flowers with a light fabric (such as cheesecloth) and a rubber band to protect the heads from the birds.
- Alternatively, you can cut the flower head early and hang the heads upside down until the seeds are dry; hang indoors or in a place that’s safe from birds and mice.
- Rinse sunflower seeds before laying out to dry for several hours or overnight.
- If you’re saving seeds to replant, store them in an airtight container in a cool, dry place until you are ready to plant.
Read our complete article on harvesting sunflower seeds here.
Recipes
Cooking Notes
Just one ounce of sunflower seeds contains about 6 grams of protein and 14 grams of oils. The fats are almost entirely unsaturated with 9g of polyunsaturated and 3g of monounsaturated fats per ounce (NSA). The oil is high in linoleic acid and is a good source of vitamin E.
- Some varieties produce small black seeds used in cooking oil, margarine, cosmetics, and animal feed; they are the best sunflower seeds for attracting the greatest variety of songbirds.
- The bigger, striped seeds are grown for snacking and as an ingredient in bread and health foods. They, too, are used for feeding birds, especially larger species, such as jays and mourning doves.
How to Roast Sunflower Seeds
Re-soak seeds overnight in salted water. Run through a strainer and dry on a layer of paper towels.
Bake for 25 to 30 minutes at 325 degrees on a baking sheet. Seeds should be spread out in a single layer. Stir frequently during the baking and remove seeds when they look slightly browned. Don’t burn!
That’s it! You can add some olive oil, salt, and spices to your roasted seeds if you wish.
Or, you can also make suet cakes for the winter birds! See how to make suet.
Catherine Boeckmann
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So it has survived, and 2 new stalks appeared like any other pruned plant.
So followup up question is this, it appears to be tracking the sun does this mean it'll get heads or would plant do that anyhow? I've never grown sunflowers so I have no clue what to look for (likely too early to see new heads anyhow).
Thanks
Glad to hear there is more growth, however it is still unlikely there will be more blooms. It takes a lot of energy for the plant to grow the flower head, so if it was cut off prematurely, there isn’t enough energy to complete the task twice. The sun tracking is normal behavior for all plants and isn’t an indication of blooms. However, nature is astounding in many ways, so don’t give up on that flower yet!
My daughter's first grade class planted sunflower seeds in Styrofoam cups for mother's day gifts. My plant is appx 12 inches in height but saggy. I think the roots might have been water logged. I poked holes in the bottom of the cup today and lightly watered it and placed by a window. Is the sagginess normal when they are still little?
Also, I live in south Texas where there's plenty of sun and heat. Could I transplant to a pot or must it be in the ground?
It sounds like you need to get your sunflower out of its cup. You can plant the sunflower in a big, deep pot. The taller sunflower varieties also get top heavy and may start leaning. If you grow them in pots you may need to support the stalks against a wall or a fence.
Advice please. My 5 year old son was given sunflower seeds from school in pot. Grew in south facing kitchen window sill. They are now approx 18 inches in height. There are 2 gorwing in pot. When should I plant outside bearing in mind we live on the North East coast of England. (Tyne & Wear) feel free to google.
Mark you can plant out your sunflowers now if you put something over them to protect against the wind and frost.
I planted mine out 2weeks ago under a mini Polly tunnel they are doing really well and i live on the North Norfolk coast.
i am going to set up rows of stakes and string across the plot sturdy line for the plants to lean on as they grow. i know many taller sunflowers really need this type of help, but maybe the shorter ones will enjoy this same type of help. i really have enjoyed this forum so i hope i can refer back to you with progress reports on the SUNFLOWER PATCH i have got just about ready to plant i just wondered that birds can just easily dive down and peck up my seeds even before they sprout. i guess i have to drape netting over my plot too. who has had a strong crop before of sunflowers and how did you set the plot up for them?
It is a good article for beginners. Some highlight may be referred for special care.
Thank you for the great information on all your flowers!
I've been feeding the wild birds where I live sunflower seeds in a feeder. I read somewhere that you shouldn't stop feeding birds once you start feeding them. I have to move so should I plant some sunflowers for them so that they can eat the seeds? I'll feed the birds where I move to, but I'm worried about the ones that I feed now.
