Getting rid of powdery mildew

White, powdery mildew and leaf rot on plant.If you grow plants at home, in a garden or indoor grow tent system, at some point you’ve probably noticed white, powdery mildew on your plants. You may see small areas of white or grayish-white on the leaves, stems, or flowers of your plants around spring and summertime. You’ll likely notice these spots appearing on fruits and vegetables, too.

This white, powdery mildew is especially prevalent among flowers, cucumbers, and grapes. Practically all plants are fair game, though, so you’ll have to be mindful with the measures you take to treat and prevent mildew in order to keep your plants safe.

In this article we’ll explain what causes white, powdery mildew and how you can get rid of it. We’ll also give you some important tips to prevent mildew from coming back.

Table of Contents

  1. What Causes White, Powdery Mildew on Plants?
  2. How Powdery Mildew Harms Plants
  3. How to Get Rid of Powdery Mildew
    1. Use a Fungicide
    2. Remove the Affected Areas
    3. Take Preventative Measures
  4. Treat Powdery Mildew on Plants or Prevent It Altogether

Okay, let's talk about what causes mildew on plants and what you can do to prevent and treat it.

What Causes White, Powdery Mildew on Plants?

White, powdery mildew on grapes.Mildew on plants is actually a fungus, and it tends to show up under specific conditions. The following are the typical causes for white mildew on plants:

  • High humidity
  • Dry leaves
  • Warm climate
  • Lack of sunlight

Plant mildew thrives in these environments. It’s made worse in areas where plants are packed together without much airflow, and it will quickly cover the majority of your plants if you are not careful.

How Powdery Mildew Harms Plants

Leaf damage and powdery mildew on plant.While this fungal disease typically won’t completely destroy your plants, it can be harmful. As such, you should treat it right away to avoid any potential damage to your plants.

Mildew will make your plants less aesthetically pleasing, but it can also make your plants susceptible to a host of other issues:

  • Impaired photosynthesis leading to hindered growth.
  • Overheating and sunburn due to a lack of strength.
  • Smaller yields due to weaker plants.
  • Less flavor or potency for fruits, vegetables, and buds.
  • Higher susceptibility to insect damage and slower recovery from damage.

Powdery mildew is parasitic, and like any parasite, it weakens its host gradually. Its fungal spores will break a hole in the epidermis of your plants or grow in the stomata, taking nutrients and even harming the roots that help plants absorb water. Your plants will grow progressively weaker until they die from a lack of nutrients. Worse, they can fall prey to insects and other pests and will be unable to recover even after the infestation is gone.

Mildew on plants is typically easier to get rid of than pests and other fungi. That said, it still spreads quickly. It’s important to keep an eye out for white, powdery mildew so you can get rid of it immediately and prevent it from thriving.

How to Get Rid of Powdery Mildew

White, powdery mildew is problematic, but isn’t the end of your garden’s life. In fact, there’s a three-part approach to getting rid of mildew and keeping it gone.

Use a Fungicide

Spraying fungicide on flowers

When applied properly, fungicides and mildew removers can help prevent the mildew from spreading from an affected area to the rest of your plant (or any of the other plants in your garden or grow tent). Most fungicides will help deteriorate the spores and kill them off, so all you have to do is rinse your plants and wipe them down.

We recommend using Sierra Natural Science 244 Fungicide, which eliminates a good amount of fungus and lowers the lifespan of remaining fungal spores. It also strengthens plants so they can fight this fungal disease, and it protects the plants from being infected in the future.

Note: Make sure to wear gloves before you apply a fungicide to your plants.

Remove the Affected Areas

Trimming leaves affected by white, powdery mildew.If fungicide isn’t working as well as you’d hoped, it’s best to cut off the affected parts of your plant. You may notice that only a few leaves or pieces of fruit have mildew on them. When that’s the case, simply use plant clippers or trimming shears to remove these damaged areas.

If you opt to remove the parts of your plants that are affected, you’ll want to start as soon as you notice any white, powdery mildew. You’ll also want to carefully separate each infected plant to ensure the spores don’t get onto the rest of your plants while clipping the damaged parts.

Take Preventative Measures

The adage “prevention is better than cure” is definitely true when it comes to taking care of your plants. If you make sure that your plants are grown in conditions that are not conductive to mold and mildew growth, you won’t have to worry about getting rid of this fungal disease.

Trimming leaves damaged due to powdery mildew.There are many steps you can take to prevent plant mildew:

  • Provide adequate space between your plants.
  • Prune your plants frequently to prevent crowding and help airflow.
  • Choose plant options that are less susceptible to mold and mildew.
  • Improve your grow’s air circulation and ventilation using fans.
  • Use neem oil like Dyna-Gro Neem Oil to protect your plants’ stomata and keep the leaves healthy and shiny.

Mildew prevention is essential for growing strong, healthy plants. If you follow these steps, you’ll know how to kill mold and mildew and protect your plants in the future and even prevent it from affecting your grow.

Treat Powdery Mildew on Plants or Prevent It Altogether

White powdery mildew and fungus on plant leaves.The next time you spot powdery mildew on your plants’ leaves, flowers, fruit, or stems, don’t worry, but be reactive.

You can treat this fungus easily by using plant clippers and fungicide, effectively removing mold and mildew from your plants. You can also take preventative measures to keep your plants in great condition and stop white, powdery mildew from appearing again.


Hi Aeron! If you’re trying to get rid of spider mites, you can’t go wrong with neem oil. You’ll want to mix a bit of neem oil with water and use a spray bottle to spray the affected plants.

Martin Linskey

I found that NEEM Oil works very well. I had Spider mites at one point and the little white flies, also had black spots growing on one plants leafs which is supposed to be deadly to the plant. NEEM Oil fixed it all, and is a regular part of my plant treatment.


What’s the best thing for getting rid of spider mate

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