Can Sunflowers Still Grow in Harsh Conditions?

Sunflowers are one of the most iconic flowers that you can add to your garden. But just like any flower, it’s important you understand the conditions that sunflowers do best in before you plant them. Therefore, you may be wondering if sunflowers can grow in the harsh conditions that your garden might be exposed to.

Sunflowers can still grow in harsh conditions. Sunflowers are able to grow strong in conditions that might be too much for other plants, including intense heat or periodic droughts. However, there are certain conditions that are best suited for sunflowers for optimal growth.

Wondering if you’ve got the right conditions in your garden to grow your sunflowers to their fullest potential? The rest of this article will give you more information about how to provide this iconic flower with the conditions that it needs to thrive.

What Conditions Are Suitable for Sunflowers?

Sunflowers are remarkably hardy flowers that can thrive in a variety of different conditions. The fact that sunflowers grow in all 50 states in the US shows you the wide variety of different environments that are able to support this flower. They’re quite a forgiving plant that can tolerate a wide variety of conditions and grow strong through most adversity.

The conditions suitable for sunflowers include a temperature of 70-78°F (21.11-25.55°C), at least six hours of direct sunlight a day, adequate watering, and a nice quality, well-draining soil. However, sunflowers are durable even in harsh weather, so they can still thrive in unsuitable conditions.

Read on to get more familiar with the different conditions that sunflowers grow best with. This includes the level of sunlight that sunflowers thrive with, how much to water them, and the type of soil they should be planted in to create the most ideal conditions for growth.

Sunlight and Heat

As their name might suggest, sunflowers do best when they’re exposed to plenty of sunlight to give them the energy they need. The ideal lighting for sunflowers is full sunlight. This means that you should plant these flowers somewhere they’ll be exposed to six hours or more of sunlight per day. Sunflowers can grow in shady conditions, but they won’t thrive to their fullest potential as they would with full sunlight.

When sunflower seeds are planted, the soil they’re sown in should be between 55-60°F (12.77-15.55°C). Once the flowers grow, the ideal temperature for them to thrive is between 70-78°F (21.11-25.55°C). However, this flower is known for its ability to withstand periods of extreme heat, so it can still grow strong outside of this temperature range.

Hydration Requirements

Sunflowers are known for being an extraordinarily drought-resistant plant that’s able to withstand long periods without water. 

On the other hand, this flower is also able to withstand wet and humid conditions as long as the soil it’s planted in doesn’t become waterlogged. This gives sunflowers a very forgiving nature when it comes to how much water they receive.

However, in order to achieve this hardy character, sunflowers need to receive adequate water when they’re in their early stages of life and are still developing their root system. 

To encourage your sunflowers to grow as big and healthy as they can, you should also provide them with supplemental water during long periods without any rain.

If you want to learn more about how long sunflowers last without water, you can read my other article here: How Long Do Sunflowers Last Without Water?

Type of Soil

As we have seen, sunflowers are able to withstand a variety of different conditions without any issues. The same holds true for the kinds of soil that sunflowers can thrive in. As long as the soil isn’t waterlogged (which can lead to root rot), sunflower seeds can grow in most different types of soil.

However, sunflowers do best when planted in soil that drains quickly. Soil that’s sandy or loamy creates the ideal conditions that sunflowers like best. Sunflowers do best in PH-neutral soils, but they can tolerate soils that are slightly acidic or slightly alkaline as well, consistent with their overall forgiving nature.

Tips for Growing Sunflowers

Want more advice on how to help your sunflowers grow healthy and strong? In addition to creating the right conditions to encourage your sunflowers to grow, use these tips below to get the best results in your garden.

Choose the Right Type of Sunflower

Sunflowers come in a few different varieties that each have their own characteristics that might better suit your needs. 

On one end of the spectrum, there are mammoth sunflowers. These flowers can grow up to an astounding 12-feet (3.65 m) tall, giving them the towering height that this flower is known for. This large flower has a large root system to match and consequently needs plenty of space to grow properly.

However, on the smaller side of things, you can choose to grow dwarf sunflowers. These plants grow much shorter and don’t have as extensive of a root system, making them the ideal choice if you want to grow potted sunflowers. If you want to know more about what kind of sunflowers to grow, you can use this guide to give you some ideas.

Space Your Seeds Adequately When Planting

Plants all need sunlight, water, and nutrients from the soil. When plants occupy the same area, they begin to compete for these valuable resources. This is especially important to keep in mind with sunflowers, given that the larger varieties of this plant grow extensive root systems. Planting your sunflowers too close together risks stunting the growth of both plants.

Depending on the type of sunflower that you’re growing, you should leave between 6-36 inches (15.24-91.44 cm) between the spaces you plant each sunflower, digging holes about one inch (2.54 cm) deep for each plant. This will allow each sunflower to get the resources it needs to thrive.

Don’t Over-Fertilize Your Sunflowers

Fertilizer provides an important boost of nutrients that helps your flowers grow. For your sunflowers in particular, look for a water-soluble fertilizer that’s high in nitrogen.

However, it’s also important that you don’t over-fertilize your sunflowers. This can cause the plants to grow with weak stems, preventing the flower from reaching full height. Using a slow-release fertilizer in the soil during the early stages of growth can help to avoid this issue.

Protect Your Seeds and Seedlings

When sunflowers are still at the seed stage or are in the very early stages of their growth, they are at their most vulnerable to garden pests, diseases, and damage from the elements. That’s why it’s important to provide your seeds and seedlings some extra protection during this vulnerable stage in their life.

I recommend using a plant cover to provide additional protection for your plants when they’re most vulnerable. This will increase the chances your sunflowers make it through this risky portion of their development, so you’re able to see them grow to their full beauty. 

Add Some Structural Support

Smaller varieties of sunflowers can usually support themselves with their own stems. However, the taller varieties of this flower that have heavy blooms, such as the mammoth sunflower, may need a little help standing straight and tall. You can use supports to give your flowers some added stability and help them grow to their full height.

Growing your sunflowers near a fence or a stake you’ve planted in the ground makes it easy to provide the necessary support. You can use ties to secure the stalk of the plant to the support so they have the structure needed to continue growing upward. 

Bits of cloth from discarded clothes make cheap and useful ties, but be gentle with your flowers when applying the ties to avoid causing any damage.

Final Thoughts

Sunflowers are among the hardiest flowers that you can add to your garden. They can withstand harsh conditions, flourishing in many different kinds of soil and through long periods of minimal water. They’re also able to withstand exposure to the harsh sun and hot, dry conditions.

Providing physical support, nutrients, and the right amount of water will help your sunflowers reach their full potential. However, you should still protect your plants when they’re in the seed and seedling stage. Follow these tips, and you’ll have this beautiful flower towering over your garden in no time at all.

Alexander Picot

Alexander Picot is the principal creator of, a website dedicated to gardening tips. Inspired by his mother’s love of gardening, Alex has a passion for taking care of plants and turning backyards into feel-good places and loves to share his experience with the rest of the world.

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