A Complete Guide to Powdery Mildew and Keeping Your Plants Healthy

Whether you’re a first-time gardener or a seasoned pro, gardening is hard work and it’s tough watching for all the potential pests, pathogens and problems that can show up and damage your precious crops. Many new growers, including us when we got started, don’t know what all the different jargon stands for. While there are dozens of problems you should be aware of while running a grow operation or a farm, powdery mildew is one of the most problematic, and easily preventable issues that you’ll encounter. Powdery mildew can literally kill off your entire harvest if you aren’t careful. Whether you grow inside or out, there’s always a risk for the fungus to spread to your crops and leave them weak, sad looking and starved for sunlight. That’s why we put together a guide in powdery mildew explaining exactly what you can do to avoid the problem entirely. Read through the guide and you’ll learn what to watch for, and how to react if you notice mildew affecting your crops. Whether you spot the mildew the first week of your grow, or you see powdery mildew on week 7, there are steps you can take to keep your plants healthy. Read on and find out what you can do.

A Complete Guide to Powdery Mildew and Keeping Your Plants Healthy

Understanding Powdery Mildew

Powdery mildew is a pesky fungus that grows over top of the leaves of many different plants. The mildew doesn’t kill plants directly, but it can lead to poor production and eventually death indirectly. The mildew grows along leaves on many different types of plants. The fungus starts off slowly, but can spread rapidly.

After finding a spot to grow, small little bits of white form along the plant. They look like powdered sugar, but will spread to larger spots over time. Eventually, the mildew spreads over most of the leaves of a plant, causing them to turn yellow, get weak and die. It’s a minor problem that can quickly turn serious for your plants, which is why it’s so important for you to understand the problem.

What Causes Powdery Mildew?

Powdery mildew is caused by a special fungus that thrives in cool, damp environments with minimal airflow. When the right set of conditions exist the mildew can grow and spread with ease and cause all sorts of trouble throughout your garden.

Why is Powdery Mildew Problematic?

Not only can powdery mildew cause health issues when contaminated leaves are ingested in any way, but it can cause health problems in your plants as well. Even though the mildew doesn’t specifically attack your plants, it slows or even stops the photosynthesis process. Photosynthesis is key to plant growth and plants with inhibited photosynthesis end up being small, weak and producing a poor crop yield. No matter what sort of plants you’re growing, if they’re not going through photosynthesis the way they should be, you’re going to be left with an unimpressive yield. Not only is powdery mildew a serious risk for your plants, it can also be a risk to your health or your customer’s health if it infects a crop that’s later consumed. Smoking powdery mildew can create real health issues and will also make your product seem like a low quality option that will scare away future buyers. The last thing that you want is to have powdery mildew on buds, which is why you have to take care of the problem before it has a chance to spread that far.

Powdery Mildew Spreads and Persists for Multiple Seasons

The fungus that causes powdery mildew is particularly problematic because it spreads through the air in later stages, and it can live on plants through multiple seasons if they aren’t removed from the area. That means, you could be fighting this fungus for many seasons if you don’t properly deal with it the first time. There could be a powdery mildew weed sitting at the edge of your garden box right now, just waiting to spread its sickness to your important crops. Whenever you deal with a plant that suffers from powdery mildew, make sure you remove it from your growing area so you aren’t fighting a perpetual problem.

When you deal with powdery mildew outbreaks indoors, you should also try and limit air flow over infected crops, because the spores spread through the air and good air flow can help them spread more rapidly to your other healthy plants.

A Complete Guide to Powdery Mildew and Keeping Your Plants Healthy

Identifying Powdery Mildew

As a serious grower you need to understand what powdery mildew looks like and also what stage the fungus is in depending on how your crops look. Learn to recognize the problem and you’ll know what you can do to treat it when it shows up. Fail to recognize it and you’ll be left wondering what you should do for your failing crops.

Early Signs to Watch out For

Knowing how to spot powdery mildew sooner, means treating your plants faster and keeping your grow in better health. That’s why it’s important to look for these early signs while monitoring your grow for health.

  • Small sections of gray or white fungus on the upper portions of the leaves, usually on the fan leaves first. It starts off as tiny white bumps and progresses.
  • Even before the mildew shows up, bushy and damp sections of your garden are likely spots where the mildew will show up. If you see an overcrowded section in your garden, or an area where sun can’t reach all the plants, you have a location that’s ideal for powdery mildew contamination to occur.

What You Can Do About Powdery Mildew

It’s one thing to know about how to spot powdery mildew after it’s already on your plants, but it’s also important to know how to treat any mildew that you do find, and how to prevent the fungus from attaching itself and growing in the first place. Below we explain just how you can deal with powdery mildew cropsor any other type of plant that the fungus is affecting.

Eliminating Risk Factors

One of the best things you can do to prevent powdery mildew from affecting your grow, is to reduce your risk factors as much as possible. Keep the below recommendations in mind when operating your grow, and you’re less likely to run into issues with fungus and mildew in general.

  • Manage Humidity Levels – Humidity levels over 60 percent dramatically increase your chances for powdery mildew to develop on your crops.
  • Space plants out as much as possible – Overcrowding your plants is never good to do, and it can help the fungus spread between your plants, and encourages higher humidity levels to develop as well.
  • Invest in Good Ventilation – If you’re growing indoors or in a greenhouse environment, make sure your plants have ample ventilation. This can be achieved by installing oscillating fans and an air extractor system. A dehumidifier is an excellent option for closed systems.
  • Implement a quality light and pathogen prevention tool like the BioRadiance BRe3 wand that boosts growth while eliminating pathogens.
  • Practice Good Canopy Management – Keep excess fan leaves trimmed and carefully prune your plants to allow sufficient airflow to make it to the inner layers of the canopy.
  • Choose clones with care – It’s important to obtain your clones from reputable growers, because it’s possible for clones to be infected with mildew without you know it. The problem will show up later after you establish the clones, and then you’re forced to act fast to eliminate it.
  • Avoid low temperatures – When growing indoors it is easy to control your growing temperatures. Powdery mildew sets in most commonly when the growing temperature is 68 degrees Fahrenheit or less. By keeping temperatures safely above that level you will minimize your problems with the fungus.

Taking Care of Powdery Mildew After It Sets In

If you’re a serious grower plagued with the fungus, you’re probably wondering “How do I treat powdery mildew?” The answer is that it depends. There are a few different treatment options proven to work, though the best tool is a powerful light called the Bio Radiance BR3e. This powerful light effectively kills bacteria and fungus when installed properly. Not only does it eliminate those harmful pathogens, it also boosts plant growth, enhances root development and can help improve clone production. The BRe3 isn’t a UV light, and offers better penetration results than UV lights. Not only that, but can effectively kill off powdery mildew in just 24 hours after installation.

BioRadiance Wand BRe3

If you don’t want to invest in the BRe3 light, the next best option is a sulfur vaporizer, but they must be used with care. Install the vaporizer to operate for approximately 10 hours at night, and take care to evacuate all the air away before turning any lights on in the space. Use the sulfur vaporizer improperly and you can do real harm to your plants.

You can also apply a commercial product known as Eagle 20 to your plants to reduce issues with powdery mildew. Many agricultural states require a pesticide applicator’s license to purchase it and use it. It is strong and effective. Make sure to coats your plants heavily before taking effect. Otherwise, most of the home remedies represented as a powdery mildew treatments such as baking soda or Safer Fungicide don’t work fast enough and deliver unimpressive results compared to the BRe3 wand light. In order for them to have a chance at working them must be applied very early on, and more serious infestations are almost impossible to overcome.

Once you notice infected plants, you must also consider whether or not you want to remove the powdery mildew from the rest of your plants. Most of the time if you treat the area using the BRe3 wand you can restore your plants back to good health. If you’re relying on one of the other methods you could end up having to separate the healthy plants from the unhealthy ones. The fungus spreads from one plant to another, and sometimes it’s best to take out one heavily infected plant to spare the rest. If the plant is too far gone to survive you should remove it far from your grow area, and make sure it doesn’t get composted or you could re-introduce the fungus into your next batch of plants.

A Complete Guide to Powdery Mildew and Keeping Your Plants Healthy

How you handle a powdery mildew infestation really depends on how serious it is and what your growing conditions are. Be careful to assess the situation and to try the most proven options first if you can before investing in the more serious measures like removing infected plants. Most outbreaks can be controlled if you move quickly, but only if you’re willing to invest in effective tools like the BRe3 wand and install it over your plants properly. Watch your plants closely and react fast when you notice the early signs of mildew and management should be simple, or better yet, just invest in the BRe3 light now, boost plant production and avoid issues with powdery mildew later.

The Powdery mildew fungus is a serious menace to growers all over the country, but it’s nothing that you can’t beat! By following our tips for identifying the fungus, isolating it from your plants and treating the problem before it can spread, you can successfully grow crop after crop without issue. Follow careful preventative practices and you might not ever have to treat the mildew problem at all.

If you would like to learn more about powdery mildew and how to keep your plants healthy, read through some of our favorite resources provided down below. They’ll help you understand the problem even more accurately and should help you grow with a restored level of confidence.

  1. Understanding the Benefits of the BioRadiance BRe3 Wand 
  2. Treating Mold on Plants
  3. Properly Ventilating a Grow Room
  4. A Powdery Mildew Fact Sheet
  5. A Scientific Explanation of Powdery Mildew

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