Complete Guide to Grow Sunflowers

Cultivo de girasoles

Translated by Nick R

Sunflowers are ornamental plants highly prized for their beautiful, distinctive flowers but also quite cultivated for their renowned seeds. Plus, growing sunflower plants is easy because they tolerate heat, resist pests and grow fast. – What more could you ask for?

So, whether you want to grow this flower to brighten up your garden, to harvest its seeds, or because you’re going to use it in bouquets, we have excellent tips that will make your flowers grow strong and healthy.

For this, we’ll talk about the characteristics of sunflowers and everything that has to do with their sowing and care process. Also, we will finish by recommending 5 varieties of this plant that you’ll love for sure.

Characteristics of sunflowers 

Cultivation of sunflowers in the garden

Botanically they are called Helianthus annuus. On one hand, annuus is because it is an annual plant, and helianthus comes from the Greek words helios meaning “sun”, and anthos, standing for “flower”.

However, they are commonly named sunflowers since the heads of the flowers move to follow the sun’s path every day. In addition, a further trait is that their large flowers resemble the sun’s rays.

It’s a plant native to the American continent, but especially to central and northern America. It’s fast-growing as it usually flowers 80 to 120 days after the germination of the seeds. Its life cycle takes about a year to complete.

Botanical Description 

Sunflowers grow on green, hairy, robust, erect stems that can reach up to 3 m (10 ft) tall. They may contain a single flower or branch out into multiple flowers.

Their leaves are also hairy, rough to the touch, and can be oval or triangular. The number varies between 20 and 40 leaves, depending on the species. Moreover, its flowers come in various colors such as yellow, orange, red, and even brown.

When the plant reaches maturity, the flowers turn into heavy heads full of seeds that are attractive to both humans and animals, like birds. This since they contain calcium, phosphorus, and several vitamins.

When we talked about sunflowers turning their heads to follow the sun it’s because they are heliotropic plants. Therefore in the morning, they will face east, and throughout the day, they’ll incline their stems to make the most of the sunlight. Thus, in the evening, they’ll turn west, and during the night, they’ll return to their initial position to wait for sunrise again.

It’s worth pointing out that this process occurs only during the first stages of development, just before the flowers ripen and become loaded with seeds because, at this point, the heads will become heavy.

How to grow sunflowers? 

Great, now that you know a little about the characteristics of sunflowers, let’s see how you can plant and harvest beautiful new sunflowers.

1. Seeds or seedlings 

Sunflowers are grown primarily from seed as they germinate successfully and are easy to obtain from a nursery, garden store, or by trading with local gardeners.

Likewise, you can obtain them from sunflowers you already own and thus propagate them. Later in the harvest section, we’ll tell you how to collect the seeds.

Alternatively, you may get seedlings to speed up the process, although more varieties are available when growing sunflowers from seed. Besides, sunflowers are not a big fan of transplanting as their roots get stressed by it.

In either case, choose the sunflower variety that best suits your needs. For example, if you want to grow them in containers, a shorter plant is preferable or, if you want to harvest the seeds, you should opt for species that produce more of them.

Later on, we’re going to recommend 5 different types of sunflowers, but don’t forget to ask about the characteristics of the variety when buying it.

2. Planting process 

If you want to plant in the garden, try to do it at the end of winter, just after the frosts have passed.

First, loosen the soil with a rake if it’s too compact. Then create a hole about 3 cm deep and place the seed.

As the germination success rate is rather high, you should place 1 seed per hole or pot. Also, since you are planting directly in the garden, leave a space of at least 15 cm between seeds.

Finally, remember to water the planting area to provide them with water, avoiding waterlogging the soil.

Now, for potting, we recommend using a large container about 30 to 40 cm (12 to 18 inches) deep. This is because regardless of the sunflower variety, they develop a large root system and require the appropriate space.

You can also start planting in pots and then transplant them to the garden, which is convenient as planting can be done anytime; no matter how cold is outside. However, you must be careful about not mistreating the roots when transplanting.

To do so, make a hole in the soil as large as the space the plant had previously in its container. Then give it a nice spritz of water to moisten the soil and reduce the stress of transplanting.

So, although there are a few varieties of perennial sunflowers, most of them are annuals, and if you want to enjoy bloom for longer, we advise you to sow the seeds a few weeks apart.

This way, the plants will bloom at different times, and you’ll be able to enjoy gorgeous sunflowers in your garden all the time.

3. Harvest 

As we mentioned, flowering will occur between 80 and 120 days after seed germination.

If you want to cut some flowers for a bouquet or vase, we recommend doing it in the morning, as the afternoon sun can cause the flowers to wilt prematurely.

Similarly, cut the flower as soon as it blooms. That is to say, you’ll notice that your plant buds will come out, and in a few days, they’ll open; that’s when you should cut the flower for use.

The cut can be as large or short as you prefer, but it’s best to do it at a 45-degree angle diagonally. This way, the stem will absorb the water better when in the vase. Subsequently, place the flowers in water as soon as you cut them.

If you want to harvest the seeds, you can let the flower dry either when they are still attached to the stem or by cutting the head off. You’ll know they are ready when the back of the flower turns from green to yellow or brown, and most of the petals have fallen off.

This can happen 30 to 45 days after flowering. Then remove the seeds with your fingers or a fork.

Keep in mind that many birds like to feast on them, and although feeding them is good, you should be careful not to run out of seeds. You can cover the heads with a bag or simply remove them to dry in a space where they don’t get exposed.

Finally, store the seeds in an airtight container or in a bag and leave them in a dry and cool place until the next sowing.

If you wish, you can consume them once they are dry, but remember to remove the shell for easier consumption. All sunflower varieties offer edible seeds; just try not to use chemical pesticides or fungicides that are harmful to your health.

How to care for sunflowers 

Aside from sowing the seeds, you need to know what conditions sunflowers prefer to live in, so as to succeed in this crop.

Soil type for sunflowers 

Sunflowers grow best in loose, well-drained soil. This way, the roots will expand easily and grow nicely, thus allowing the flower to hold firmly to the soil and tolerate strong winds.

Most specifically, they thrive in slightly acidic to alkaline soils with a pH of 6.0 to 7.5. Of course, they do like nutrient-rich soil, so you can use homemade compost or other plant food for them.

Theoretically, sunflowers are not picky about the type of soil; what matters is that it doesn’t get too waterlogged or compacted. Likewise, it’s convenient for sunflowers to be outdoors because the soil will dry out quickly, so you should keep this in mind if you’re growing them in pots.


As you can imagine, sunflowers need to be in a sunny spot where they receive about 6 to 8 hours of direct sunlight a day. This way, they’ll bloom steady and upright.

If the plant is exposed to harsh and recurring winds, we advise you to place it near a fence or a wall so it can have some kind of backup. Likewise, having several plants together helps them support each other as well.


Sunflowers can withstand some drought; however, consistent and abundant watering will help them bloom. You may water them 2 to 3 times a week depending on the weather conditions, making sure to water them regularly.

Therefore, let the topsoil layer dry before watering the plant again. Even if it gets rainwater, it’ll be much better since you won’t have waterlogging problems if using the appropriate type of soil.


Sunflowers don’t need fertilizing unless they’re planted in poor soil with a lack of nutrients. If so, they’ll be pleased with a product with a high phosphorus (P) content which promotes and strengthens flowering.

You can apply it during the growing season or before and during flowering.

Pests and diseases 

It’s actually a pest-resistant plant, but you may have problems with birds that love to feed on the seeds. Similarly, it can be attacked by moths, which will leave their eggs in the sunflowers and hatch tiny white larvae that will feed on the plant too.

As for diseases, remember that, for them to emerge, the plant must be weak and vulnerable. So, watch out for excess moisture in the soil, or your plant could suffer from powdery mildew or rust.

To avoid or fix that, cover the sunflower heads when they’re maturing to protect the seeds. However, if the plant already has a pest or disease, neem oil and potassium soap will certainly help.

5 varieties of sunflowers for your garden 

Finally, we want to show you 5 varieties of sunflowers so you can appreciate how diverse they can be and get encouraged to grow them.

The ¨Big smile” sunflower 

Let’s start with Helianthus Big Smile, a short-growing sunflower perfect for potting since it is a dwarf variety. It reaches a height of 15 to 50 centimeters.

Its petals are bright yellow with a brown center. It’ll display its beautiful flowers approximately 3 months after seed germination, so, it has an early flowering that tends to branch out, producing 5 to 6 buds or shoots or buds.

But only as long as you provide it with the basic but absolutely necessary requirements, such as direct light, loose soil, and regular water.

The ¨Teddy bear¨ Sunflower

The Helianthus Teddy Bear is a rather peculiar type of sunflower that commonly reaches 1.5 m (5 ft) tall, for which it’s also included in the dwarf varieties.

It’s characterized by its fluffy, bushy flowers that look like pompoms. They also have a beautiful yellow color and usually measure 12 to 15 cm wide. Besides, it begins to bloom approximately 2 months after sowing, and several buds grow from a single stem.

It can also be grown in pots by providing a large container in which it can develop a robust root system and by placing it where it receives direct sunlight.

The Velvet Queen Sunflower 

Helianthus Velvet Queen is a sunflower variety that produces vibrant red to orange petals and has a nearly black center. Some have their entire flower of the same shade or may also have a degradé as seen in the image.

It can grow up to over 2 m (6 ft) tall and will definitely add a gorgeous visual highlight to your garden. In addition, in just 7 days, its seeds will germinate so that in a few months, you can enjoy its beautiful and colorful flowers.

The ¨Russian Mammoth” Sunflower 

As its name suggests, the Helianthus Russian Giant is one of the largest varieties and is perfect for growing in the garden. It can reach a height of more than 3 m tall and its flowers can measure up to 50 cm (12 inches) wide.

Its flowers are typical of sunflowers, with yellow petals and brown centers, only they have a large size. Of course, this plant may need sticks or other tools to help support it, especially if there are strong and constant winds.

Although all sunflowers attract pollinators, this variety is the most attractive to bees, butterflies, and other beneficial insects for your plants.

The ¨Multicolored” sunflower 

Finally, we introduce you to the Helianthus Pastiche, which has long, multi-headed stems with flowers that vary in yellow, red, white, and even beige. Its peculiarity is that it features a multicolored bloom.

It reaches a height of about 1.5 m (5 ft.), so you can also have it in a pot if you wish. It usually blooms about 2 months after seed germination.

Final Recommendations 

As you could see, sunflowers are beautiful plants that, although they may seem challenging, are actually easy to grow as long as you keep in mind their needs.

Also, we hope that you learned about other varieties of sunflowers as we often get the same picture in mind when thinking about them, but that actually offers great diversity to appreciate.

In conclusion, we invite you to add a few sunflowers to your garden and to follow our recommendations to the letter so that you succeed with them. We’re sure you’ll love them and that they’ll provide your home with a fine style.