Fungicide for Plants

Understanding Plant Fungal Diseases

There are many common fungal diseases that growers face, such as powdery mildew, root rot, blight, dollar spot and rust — plus rare fungi that sometimes appear. By applying fungicide in conditions that lend themselves to disease (such as high humidity), or at the first sign of symptoms, you can spare crops from these silent but deadly attacks. The fungicide either sits on the plant surface to form a physical barrier or soaks in to cause an immune response.

Fungi are naturally present in soil and on plant surfaces, and not all fungi are harmful:

• Beneficial fungi, such as mycorrhizae, form symbiotic relationships with plants, helping roots absorb nutrients and water more efficiently.
• Parasitic fungi, however, invade plant tissues and disrupt normal growth, leading to visible symptoms like spots, wilting, mold, or decay.

Recognizing the difference between beneficial and disease-causing fungi helps growers make informed treatment decisions and avoid disrupting healthy soil biology.

Keep Plant Fungi Away 

We offer a variety of fungicides with different active ingredients to target certain diseases. Browse sulfur fungicide, copper fungicide, bacillus fungicide and more. They can be applied in many ways, including liquid sprays and drenches, granule dusts and even seed treatments. Some fungicides also control certain pests and even weeds, and others may help with plant rooting and color. However, you should check the label first to confirm efficacy before using them this way.  

Choosing the right plant fungicide option depends on crop type, disease pressure, and your overall growing strategy.

• Natural or biological fungicides (such as sulfur, copper, and bacillus-based products) are often favored for their lower environmental impact and compatibility with organic growing practices, though they may require more frequent applications.
• Chemical or synthetic fungicides can offer longer-lasting protection and broader-spectrum control, but may carry stricter handling requirements and potential resistance concerns if overused.

Reliable Fungicide Formulas at Great Prices 

Greenhouse Megastore has partners with Bonide, Espoma, Hi-Yield and other leading pesticide brands to offer high-quality plant fungicides for professionals and hobby growers. Whether you need a single small bottle, fungicide concentrate or bulk containers, we will help you get the right plant fungal control product with a Price Match Guarantee. Call us toll-free at 1-888-281-9337 for knowledgeable assistance from a sales associate. 

Fungicide FAQs

Is baking soda a fungicide?

Baking soda (sodium bicarbonate) can act as a mild fungistatic agent, meaning it may help slow the growth of certain fungal diseases like powdery mildew when applied as a foliar spray. It works by raising the pH on the leaf surface, creating conditions that are less favorable for fungal development. However, baking soda is not a registered commercial fungicide and is typically less effective than labeled products designed for consistent disease control.

What is a natural fungicide?

A natural fungicide is a product derived from naturally occurring minerals, plant extracts, or beneficial microorganisms that help control fungal diseases. Common examples include sulfur fungicides, copper-based fungicides, and biological products containing Bacillus species. Many natural fungicides are approved for organic growing, but growers should always check the product label to confirm certification and target disease effectiveness.

When should I apply fungicide to my plants?

Fungicides are most effective when applied preventatively, before disease becomes severe, or at the first sign of symptoms. Conditions such as high humidity, poor air circulation, and frequent leaf wetness can increase fungal pressure. Following label directions for timing and reapplication intervals is critical for best results.

What’s the difference between contact and systemic fungicides?

Contact fungicides remain on the plant surface and create a protective barrier against fungal spores. Systemic fungicides are absorbed into plant tissue and move internally, helping protect new growth and sometimes triggering a plant’s natural defense responses. Each has its advantages depending on disease type and severity.