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How to Prevent Powdery Mildew

If unmanaged, powdery mildew (PM), mould and fungus can easily devastate a crop. Next to harmful pests, PM is the single most damaging hazard in the garden. PM on plants promotes deficiencies, reduces quality, impairs yields, and severely devalues a crop. If left unchecked, powdery mildew can even encourage rot in fully formed flowers, or worse, curse a grow room with systemic issues of mould, fungus and plant disease. While fairly common, powdery mildew is a potential hazard that can be easily prevented. However, if problems do arise, products and solutions are widely available to help treat and prevent powdery mildew. Read the following passages to find out more about powdery mildew and solutions available for treatment and prevention.

What is Powdery Mildew? 

Powdery Mildew creates white patches of fungal growth that stand out against the green leaves. 

Powdery Mildew is a fungal disease that is common in a wide variety of plants and typically forms in white splotches on the tops of large fan leaves. Powdery mildew develops fast in environments with high humidity and moderate temperatures. Greenhouses, for example, provide the best environment for the widespread development of plant diseases like powdery mildew. As destructive as PM might be, luckily, it is one of the easiest plant diseases to identify. Plants exposed to spores may appear to have been dusted with flour, as powdery mildew starts off as small, circular white spots and later develops into widespread patches of white mildew that can be wiped or brushed off.

What Causes Powdery Mildew? 

Weak genetics, an unstable environment and irregular feeding patterns can all contribute to the development of plant disease. For instance, if a mother plant has had previously spells of powdery mildew, the offspring of that plant carries on the disease, and can also be easily susceptible to spores in the future. Environmental conditions present growers with additional concern for the spread of disease.

For example, “day-time” temperatures and levels of humidity are something every indoor gardener is concerned with maintaining. In the range of 80 degrees Fahrenheit (26C) and 50-60 percent humidity, plants have an ideal environment in which to grow. However, “nighttime” temperatures and humidity levels must also be managed and maintained. If not, spikes in humidity coupled with low nighttime temperatures may lead to an increased risk of disease development.

For the best chance of cultivating a disease-free crop:

Breed your own genetics
Maintain a consistent, stable environment
Feed your crop appropriately with nutrient supplements

How to Prevent Powdery Mildew 

If your garden’s genetics and environment are both strong and stable, powdery mildew prevention is the next step to think about on the path to cultivating the cleanest crop possible. Like pest control, the best solution for managing PM is not having it at all. So, before dealing with the headache of disease treatment, consider the options available to stop PM from becoming a problem in the first place. 

Look out for round patches of powder that looks like flour.

Environmental Control 

Identifying the environmental factors that put your plants at risk for PM is the first issue to consider when trying to avoid it. If the levels of temperature and humidity in your garden are ideal, the next step to avoiding powdery mildew is to consider the garden’s air movement, plant placement and potential sources of disease.

PM will thrive in environments with little air movement. So, to increase prevention measures, consider purchasing additional air movers like floor or wall-mount fans – with adequate air movement, all the large fan leaves in your garden should be gently swaying. “Plant placement” is equally important. Plants too close to each other, or too close to the wall will have an increased chance of contracting and spreading diseases like powdery mildew. For the best chance of avoiding the later issues that come with treating PM, make sure that all the plants in your garden have enough physical space to grow and transpire without the extra buildup of humidity. 

Here is an example of good airflow and ventilation for indoor growing.

Finally, if you’ve noticed an unexpected outbreak of powdery mildew, search your outdoor property for potential sources of disease. Plant disease is possible even in the cleanest gardens. If you manage a clean garden that has suddenly contracted PM, it’s quite likely that an outside source of mould has infiltrated your grow room. To combat this concern, consider cleaning outside sources of fungus and protect your crop with clean sources of fresh air: Intake or HEPA filters are a low-cost method of preventing exposure to powdery mildew. 

Strengthen Your Crop With Supplements 

Along with a stable feeding program, the most adept growers enrich their crops with supplements like GreenPlanet Nutrients Vitathrive and Plant Guard to reduce the development of plant disease. Vitathrive is GreenPlanet’s propagation supplement that contains a full complement of b-vitamins and elements that aid the plant through the vegetative stage. Among other benefits, Vitathrive helps to reduce the stresses that come from rapid cell growth, environmental conditions, and heavy fruit loads. GreenPlanet’s potassium silicate supplement, Plant Guard, also helps prepare your plants for poor environmental conditions by strengthening cell walls and increasing resistance to environmental stress and plant disease.

How to Treat Powdery Mildew 

If you’re concerned about contracting PM, inspect your crop daily for the earliest possible signs of disease. Depending on the control solution, plants can be treated for powdery mildew at any stage of growth; however, treating your plants sooner rather than later is ideal, as some treatment methods can negatively affect the outcome of plants in flower. A wide variety of treatment solutions are available for plants in the vegetative stages, these include home-remedy options, sulphur sprays or burners, and/or chemical removal. While these treatment options are effective against powdery mildew, most are not recommended during the flowering period. 

Need continued support with your crop? GreenPlanet is here to help!  For more information about the products mentioned above, please contact GreenPlanet Nutrients directly. For all other inquiries about products and services offered by GreenPlanet, contact our team or your local garden supply store for more information. 

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