How to Deal with Powdery Mildew

How to Deal with Powdery Mildew

If you notice a white fungus on your plants’ leaves, it’s most likely powdery mildew. Powdery mildew is a fungal disease which affects a massive range of plants. It takes away the plant’s nutrients to use itself, making them weaker and also prone to other diseases.

You’ll most likely find powdery mildew in environments with high humidity as it allows the fungus to spread. Depending on the severity of the powdery mildew, it can be enough to kill your plants.

Because powdery mildew is caused by fungal spores, it can also spread to other plants and grow rooms very easily. In nature, it’s carried by the wind, but it’s also carried via clothes and skin.


So How do You Identify Powdery Mildew?…

If the plant’s infected, you’ll see dusty white spots across your leaves on the upper part of the leaf. The most commonly affected areas of a plant are the young foliage; it can cause these leaves to dry out and lose their colour, making them very brittle. If you’ve got powdery mildew, it’s best to catch it nice and early.


How Can You Treat Powdery Mildew?

Once you’ve diagnosed a case of powdery mildew,  you’ll need to start strengthening your plants up and fighting the infection straight away. There’s a few key products we’d use to achieve this.

Firstly, Ed Rosenthal’s Zero Tolerance Herbal Fungicide is the perfect solution. It’s made up of concentrated essential oils which are 100% safe for humans and plants alike, unlike other fungal pesticides on the market.

When applying to your plants, we’d fully recommend you do a quick patch test due to its strength; you want to ensure you’re not going to be doing more bad than good. Although the recommended dose is 50ml per 1l, we’d recommend a much lower starting dosage of around 10ml per 1l.

For a more detailed guide to using the product, checkout our listing here.


You can also use either Ultraviolet light or Ozone to sterilize your grow space, limiting the risk of Powdery Mildew. The Solacure Flower Power Lamp Fixture provides your grow room with UVB & UVR8, two essential ranges of the UV spectrum which give your plant an incredible amount of benefits.

Firstly,  you’ll see more compact, denser flowers and less ‘legginess’ during the flowering stage. UVB exposure reduces how much taller plants get during flowering, as the plant converts energy from growing taller stems into producing more unique plant compounds, increasing your plants quality.

Secondly, it kills / suppresses powdery mildew.  Solacure lamps are also proven to help eliminate powdery mildew and other moulds which cannot live in a high UV environment. It even creates a hostile environment for insect pests such as spider mites.

They’re an incredibly cost effective way of keeping your crop healthy and free of powdery mildew.


With Ozone, you’d look to sterilise the air around your grow space, keeping those spores at bay.  We’d recommend an Uvonair in room generator. So how does it work?…

Ozone neutralises odours and inhibits moulds and bacteria in the air. Uvonair in-room ozone generators produces enough ozone to help keep the air fresh and clean in areas up to 5000 cubic feet for the larger sized units.

Ozone is a fantastic way of preventing the spread of Powdery Mildew spores.


If your plants have suffered from powdery mildew and are on the mend, we’d recommend using a silicon based product to strengthen your plants.

Mr Danks uses silicic acid –Mr Danks’ Special Boost massively increases development in all areas by utilising a patented formula that was originally developed to help plants thrive in the extreme heat of the Oman desert. It’s formulated with a complex of amino acids and silanol, and it works by delivering a super-available form of silicon that makes your plants act like they’re on steroids, creating a strong and sturdy platform for massive growth.


Once you’ve got your environment clean and sterile, it pays to keep it that way using a product like Silver Bullet Mist.

The silver stabilised peroxide disinfectant works effectively to remove biofilms and keep your grow space as clean and disease-free as possible. This provides an environment where your plants can thrive and stay healthy, especially through warm weather when the bad microbes thrive! While Silver Bullet Roots takes care of your plant’s root-zone, Silver Bullet Mist is designed for cleaning and disinfecting all the surfaces and equipment in your grow-space.


Last, but definitely not least, you’ll need to combat the powdery mildew’s ideal growing conditions by reducing the moisture in the air. A dehumidifier would help to keep levels within reasonable ranges, ensuring that plant growth does not slow down and that fungal infections don’t take hold. The RAM Dehumidifier can extract up to 10 litres of water from the air per day.


A combination of all of these methods would help to ensure your plants stay healthy, whilst giving you many other benefits.

If you want to learn more, get in touch or pop in store!

Happy growing!