How to Grow and Reap the Fun of Sunflowers

Nothing screams summer like a field of bright, yellow sunflowers, or sunflowers growing in your garden. Sunflowers are one of the easiest flowers that you can grow in the garden. They’re great for new and young gardeners to try, especially because the size and color can be quite exciting.

Sunflowers got their start thousands of years ago. We know that the Native Americans in the Southwest and along the Mississippi River cultivated sunflowers as a source of medicine, seeds, fiber, and oil. They were also used in Russia as a source of oil that didn’t break church laws.

Sunflower Varieties

You probably picture the common, yellow, large sunflowers that you see in pictures, but you may not know that sunflowers come in a variety of sizes. Some gardeners prefer the dwarf sunflowers, which only reach about a foot and a half tall. Giant varieties can reach over 12 feet tall!

Sunflowers come in many colors aside from the classic yellow. You can find them in several colors, from pale yellow to burgundy reds, and all shades of yellow, orange, and red. You can grow a field of multi-colored sunflowers.

Some varieties have different petal counts as well. The single layer of petal varieties is the most common. However, you can find varieties with double or “teddy bear” petal layers.

Here are a few varieties to try:

Mammoth: this variety is the towering, traditional sunflower that is a great snack. It acts as a bird feeder, and it’s the common plant that you pick when you think of sunflowers.
Autumn Beauty: this variety is beautiful and has some of the most incredible cultivars. It has many 6-inch flowers in several shades of colors. This variety comes in yellow, bronze, and mahogany, branching up to 7 feet tall!
Sunbeam: another variety you might want to try is called Sunbeam, and it’s a bouquet flower. It’s the Van Gogh sunflower that has a 5-foot stem with 5-inch flowers. The nice thing about Sunbeam Sunflowers is that they are large and pollenless flowers.
Teddy Bear: this sunflower variety is only 2 to 3 feet tall. It’s a small flower that’s great for small gardens or garden beds. They’re great for containers as well. It grows deep-gold, 5-inch blossoms, perfect for vases.

Growing From Sunflower Seeds or Plants?

You have two choices: starting sunflower seeds or using seedlings from a garden nursery. You can start sunflower plants indoors in individual pots, but it’s even easier to sow the seeds directly into your garden.

Sunflowers are a summer plant, and they prefer to avoid frost. You can safely plant them 1 or 2 weeks before the final frost dates. They can handle a bit of a chill or two. However, if you have a long growing season, you can wait until the soil temperatures are between 55 degrees to 60 degrees F.

Picking the Best Location for Sunflowers

Sunflowers grow best in spots with full sun, which makes sense since they’re called sunflowers! It’s best if they receive 6 to 8 hours per day.

Believe it or not, these flowers are tough and able to grow in most soils, so long as it is well-draining. The soils can be slightly acidic to slightly alkaline, between pH levels 6.0 to 7.5.

Before you plant sunflowers, it’s a good idea to amend the soil with 2 to 3 inches of compost. Another choice is to use a diluted liquid fertilizer.

How to Plant Sunflowers

Planting sunflowers are easier than planting than other flowers. Here is what you need to know!

Do your best to space the seeds 6 inches apart in a trench that’s 1 to 2 inches deep. If your soil is sandy, make the trench two inches deep.
Cover up the seeds with dirt and keep the seeds watered until they germinate. Germination takes 7 to 10 days, on average.
When the first true set of leaves appear, which is the second set of leaves, thin the seeds to 2 feet apart. Sunflowers are large and they need space to grow!
Sunflowers take between 80 to 120 days to reach maturity, depending on the variety selected.
Sow a new row every 2 to 3 weeks to have blooms until the first frost. You need to space the rows 2 to 3 feet apart.

Caring for Your Sunflower Plants

These are easy plants to grow, so they can withstand a lot of neglect. The roots grow widely and can withstand drought. However, you should keep them watered regularly during the growth period, which is about 20 days before and after flowering.

It’s better to water deeply and regularly to help encourage root growth. Better root growth encourages taller sunflowers to help support top-heavy blooms.

Sunflowers don’t need to be fertilized, but they do grow vigorously, usually 6 feet in 3 months! So, it’s a good idea to add some slow-acting granular fertilizer, especially if you have poor soil that you didn’t add compost. Better soil leads to larger flowers!

However, when you fertilize, be sure to go easy on the nitrogen because it can cause a delay in flowering.

A few other tips for growing sunflowers include:

Make sure that you water around the root zone, around 3 to 4 inches from the plant. Snails and slugs love these plants, so you may want to put some baits around the stems.
Tall varieties and cultivars need support, so consider using bamboo stakes. They’re strong enough to hold the stem of any sunflower.
Sunflower seeds, leaves, and stems have a substance that stops the growth of other plants. You shouldn’t plant these flowers near potatoes or pole beans.
You don’t need to mulch sunflowers, but if you live in a dry climate, it could be a good idea. After your sunflowers are established, lay a 2 to 4-inch layer of straw or bark mulch.

Some varieties need to be trimmed and pruned. Most of the time, you plant annual sunflower varieties that produce one large head or several smaller heads. Perennial sunflowers need to be deadheaded because it encourages your plants to produce a second round of flowers in the late summer.

You can also prune annual sunflowers if you want to help reduce the height and encourage the growth of more flowers. To do so, remove the main flower bud and pinch it off. This will delay flowering, but extra side buds will form and you’ll end up with a bushier plant.

Common Pests and Diseases

While growing sunflowers is quite easy, there are several things you may have to contend with when it comes to common pests and diseases of sunflowers.

Birds and squirrels love sunflower seeds, as you might expect! You can use barrier devices, and you may want to add a white garden fleece to help catch the flower droop.
Use a tall wire barrier to keep the deer at bay.
Downy mildew, rust, and powdery mildew affect sunflowers. All of these fungal diseases can be spotted early, and you can spray the plants with a general garden fungicide.

Luckily, sunflowers tend to be insect-free. Sometimes, a small gray moth might lay its eggs on the blossoms, but you can pick those off from the plant. Seedlings can be attacked by cutworms, so you can place a cardboard toilet paper roll “collar” around the stem to help prevent damage until the plants are older.

How to Harvest Sunflowers

In the fall, it’s time to start watching for signs of maturity. The reverse side goes from green to a yellow-brown, and the large head will start to turn downward. When you get closer, you’ll notice that the tiny petals that once covered the developing seeds have dried and fallen away, exposing the mature seeds.

The trick is getting the sunflower seeds before the birds and squirrels do, which is hard. To harvest sunflowers, you need to cut off the seed heads with at least a foot or so of the stem still attached. Then, hang the heads in a warm, dry place that is well-ventilated, in an area that’s safe from rodents and bugs.

After they’ve dried, you need to keep the heads out of humidity because it can lead to spoilage from molds. Let them cure for a few weeks. Then, once they’re fully dried off, try rubbing two heads together to knock the seeds off. You can also use a stiff brush or your fingers.

Spread the seeds on a baking sheet and let them dry for a few more days. Store in an airtight glass jar in the refrigerator.

Sunflowers are Fun

Who doesn’t love sunflowers? They’re gorgeous, fun, and great for all gardeners. Kids, in particular, love to plant sunflowers and watch them grow. The bonus is they make a great snack when you’re bored or watching TV.