Why are My Sunflower Leaves Turning Brown? (Reasons & Prevention!)

The hardest thing for a gardener would be to see its sunflower leaves turning brown. You have invested your time and efforts in caring for the baby plants, ultimately finding rusty, brown, wilted leaves. But what could be the reason for brown sunflower leaves? Why are your sunflower leaves turning brown?

The main reason for brown sunflower leaves is pest attack and disease. Rust disease is a common problem that causes brown spots on sunflower leaves. It’s not a healthy sign and may destroy your entire sunflower plantation.

Why are My Sunflower Leaves Turning Brown

If you are about to plant your sunflower seeds and don’t want to see rusty-brown leaves, this article can be your best guide. If you are already facing the issue of brown sunflower leaves, there is a solution for that as well.

Keep reading this article to find out how to protect, prevent and revive your sunflower leaves from turning brown.

Reasons Why My Sunflower Leaves Are Turning Brown & Dying: The Science Behind It

Seeing your sunflower plants dying can be a real pain. You have patiently waited to see your flowers bloom, but that seems like a distant dream now. Don’t worry; such things happen to everyone, especially if you are a novice in gardening.

I have mentioned below some of the common reasons why your sunflowers leaves might be turning brown, so let’s take a look:

1. Leaf Disease

Leaf disease is one of the most common reasons for brown sunflower leaves. Leaf disease may occur due to high amounts of ph in the soil and climate changes as well. Soil with very high pH levels prevents essential micronutrients like zinc or copper from reaching the plants.

Pathogens are another cause of leaf disease. Pathogens remain inside the plant and grow along with it. When the sunflower plant reaches the time of seedling, pathogens attack it, causing brown spots in the sunflower leaves.

If not treated early, the disease may spread to the entire colony of sunflower plants destroying your whole plantation.

2. Rust Disease

Rust disease is a root cause of damaging sunflower leaves and turning them brown and rusty. A specific type of fungi called rust fungi causes rust disease in various plants, including sunflower plants.

Such types of fungi can grow on living hosts, and they destroy the cells in the leaves, ultimately causing brown spots and blisters on the leaves. Rust fungi are common in humid and moist environments, and they spread from infected plants to healthy ones.

There is no particular season for rust disease, so it may occur at any time. To control rust on sunflower leaves, pinch off one-third of the plant at a time and continue the procedure at short intervals.

3. Beetle Damage

The brown spots you see in the leaves may not actually be spots but beetles. Beetles damaging the sunflower leaves are pretty common. They would gradually eat up the leaves, preventing the healthy growth of the plants.

Spring & summer are the prime time for the beetle attack, and these tiny insects would mainly go for young plants. Therefore, you should keep an eye on the same.

4. Fungal Wilting

The name is pretty self explanatory. Fungal wilting is the result of a fungus attack on the sunflower plant and soil, causing the leaves to turn brown. Weather change is the primary cause that fuels fungus attacks.

Sunflower leaves are susceptible to weather changes. In inadequate weather, the leaves start wilting. The fungi take advantage of the weak sunflower plants and attack immediately.

It first attacks the soil, then the plant, and slowly moves towards the leaves. Fungal wilting leaves brown spots on the leaves, and sadly there isn’t a certain cure to it.

5. Glassy-winged Sharpshooter

Sunflowers are an attraction for lots of insects, including glassy-winged sharpshooters. These are tiny brown insects that feed on the sunflower nectar and also lay eggs on the leaf tissues. When the eggs hatch, they leave brown dots on the sunflower leaves.

Glassy-winged sharpshooters carry a bacteria called Xylella fastidiosa, which is harmful to the leaves and plants.

6. Excessive Heat

Excessive heat is another reason for sunflower leaves turning brown. Yes, it’s true that sunflowers need dry, sunny areas to grow and glow, but when the temperature exceeds 30°C, sunflower leaves begin to wilt, making them brown.

7. Downy Mildew

Downy mildew is a soft fluffy mass that usually grows under the sunflower leaves. It’s considered one of the worst sunflower leaf diseases as it not only damages the leaves but may also destroy the stem and buds of the plant.

Downy mildew is a common problem in humid weather. This fungal infection may make the leaves brown, pale yellow, or gray and also result in purplish-red spots on the sunflower leaves.

Common Sunflower Leaf Problems

Sunflower Leaf Problems

Apart from the ones stated above, there are other common sunflower leaf problems that need immediate care and attention. Here is a quick rundown of other sunflower leaf problems you must be aware of:

1. Dropping Leaves

Dropping leaves isn’t the sign of a healthy sunflower plant. When the plant doesn’t receive enough water, the leaves start drooping. Inspect the soil; if it feels too dry, do thorough watering till at least an inch down the plant.

2. White Leaves

Fungal infections and humid or damp weather may make your sunflower leaves turn white. These conditions induce powdery mildew; hence it requires immediate treatment.

3. Yellowing Leaves

You can tell your sunflower leaves aren’t healthy by looking at the leaf color. A healthy plant should have bright green leaves; hence yellowing leaves aren’t the best sign.

Yellowing leaves indicate nitrogen deficiency and leaf spot disease. These occur due to overwatering or water clogging in the soil.

4. Eaten Sunflower Leaves

Bugs and insects love scrapping on the sunflower leaves. If not protected well, these may damage the sunflower leaves preventing healthy growth.

How To Prevent Sunflower Leaves From Turning Brown?

Sunflower Leaves Turning Brown
Image Credit: Unsplash

Instead of whining about ruined, dying, or brown sunflower leaves, you can act smart and adopt some preventive measures to protect the leaves. Take a look at the solutions stated below to stop your leaves from turning brown.

1. Choose Nutrient-Rich And High-Quality Soil

For the sunflower plants to thrive, they need high-quality and nutrient rich soil. Sunflower seeds need at least 46 to 52% edible soil to grow to their full maturity.

Besides, these plants need high water holding capacity with pH levels not exceeding 7.5. The ideal soil type for planting sunflower seeds are – loam, silty loam, and silty clay loam.

2. Do Not Overwater Or Underwater

Providing just enough water to the sunflower plant is necessary but don’t over or underwater it. Ideally, you should water three to four inches away from the stem when the plant is young.

But when the plant matures, you should water it only once a week as the plant develops high-heat tolerance. Overwatering the plant may lead to moldy stems, ultimately ruining the entire plant.

3. Protect The Leaves From Pests And Large Animals

Pests and large animals like squirrels and birds are one of the common reasons for damaged or stale sunflower leaves. As the plants start to grow, you should cover them with plastic or paper bags to keep the leaves protected from their reach.

4. Use Pesticides And Fungicides In Moderation

Using pesticide and fungicides are a must if you want your sunflower plants to grow to full maturity. No matter how hard you try keeping them protected from bugs and insects or providing them with adequate growing conditions, there is a fair chance your plants will catch some sort of disease or fungal growth.

Therefore, to keep your sunflower plants protected from such external factors, it’s important to use pesticides and fungicides in moderation.

5. Proper Planting

To see sunflower plants thriving, proper planting is mandatory. You must keep some distance between each plant and plant them at least two to three inches deep.

If you are planting the large variety, keep at least 12 inches gap in between, and for the bouquet sized ones, keep 6 inches gap in between.

How Do You Revive A Dying Sunflower: Tips To Keep Your Sunflower Healthy

Seeing your sunflower dying isn’t the best sight, but instead of just giving up, you can try reviving it using the below mentioned tips.

1. Replant It

If it’s an indoor plant, try replanting it in a broader space with high-quality soil. The soil in the pot may become depleted over time, preventing the healthy growth of the plant.

2. Don’t Let the Soil Get Dry

Sunflower plants may die in dry soil, so water the soil if it seems too dry or if it was left unwatered for a long time.

3. Keep the Soil Nourished

Sunflowers may also die due to a lack of nutrients, so you can try using fertilizers with both micro and macronutrients for an instant boost.

4. Remove Dead Leaves and Blooms

Getting rid of the dead leaves and blooms is important to revive a dying plant. Doing so helps the plant focus its energies on the parts that still have life.

5. Don’t Water a Plant with Rotten Stem

If the stems look rotten, don’t water the plant for a few days. Watering daily may increase the stem rot; hence you should let the stems dry to get the sunflower plant back to life.


Q1: How Do I Know When My Sunflower is Dying?

When the sunflower leaves start drooping and turn brown, yellow, or black, it’s a sign the sunflower is dying. Apart from the leaves, the stems also get darker or brownish.

Q2: How Do I Know If I Am Overwatering My Sunflower?

If you see your sunflower stems are getting brown or show signs of rotting, it’s a sign that you are overwatering your sunflower.

Q3: Should You Cut Dead Leaves Off Sunflowers?

Yes, you should cut dead leaves off sunflowers. Doing so will help the plant invest all its energy in the new leaves.

Q4: How Much Sunlight Does Your Sunflower Need?

Sunflowers need about 6 to 7 hours of direct sunlight, neither more nor less. Keeping them under direct sunlight for this duration will help them bloom properly.

Final Thoughts

Hopefully, you found your answer to why your sunflower leaves are turning brown. The reasons may vary from fungal infections, insect attacks to drastic weather changes. If you want to see your sunflower plants grow tall and healthy, taking care of the above mentioned factors is necessary.

To ease your work, I have mentioned some preventive measures as well; you can try them out, and hopefully, they’ll help revive your brown sunflower leaves.

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