White Powdery Mildew

Have you seen white areas on your leaves? Are your leaves cleaned with round spots of powder that appears like flour?

If so, you’re probably handling White Powdery Mildew, likewise called White Powdery Mold or simply “WPM” to marijuana growers.

White Powdery Mildew is typically a small inconvenience that can be quickly repaired, however if you do not capture it early, WPM can develop into a disaster that ruins a whole cannabis harvest!

For those who have not skilled WPM, picture circular spots of a living, breathing, fuzzy, flour-looking compound appearing on your plant’s leaves with no caution. From there, the mildew can quickly infect other leaves and buds, rendering the buds unusable.

You’ll see “powder” on your leaves”:

Example of a pretty bad case of white powdery mold (WPM) on a cannabis leaf

White Powdery Mildew has such a simple time spreading out that even mindful growers who take appropriate preventative measures can still experience it.

Powdery Mildew

Thankfully, the problem in the photo above was quickly dealt with due to the fact that it was captured early and because White Powdery Mildew is totally reversible approximately a point.

This post will equip you with the info to stop WPM’s expansion prior to it even has a possibility to take hold!

White Powdery Mildew Defense

What’s the simplest method to eliminate versus White Powdery Mildew? Products below are recommended to prevent and treat Powdery Mildew.

AgroMagen, GrowSafe Bio-Pesticide for Spider, Organic Natural...
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Athena IPM (32 Ounce) - for Spider Mite & Powdery Mildew
Athena IPM (32 Ounce) – for Spider Mite & Powdery Mildew
Complete powdery mildew management: Control, Killer & Cure; Broad Spectrum Insecticide & Fungicide

Last update on 2024-04-22 / Affiliate links / Images from Amazon Product Advertising API

What IS White Powdery Mildew?

White Powdery Mildew is a quickly replicating (both sexually AND asexually) fungi who just understands how to do 2 things:

  1. Consume your plants
  2. Make more White Powdery Mildew

Luckily, White Powdery Mildew is simple to identify given that it develops white spots of fungal development that stand apart versus the green leaves of a marijuana plant.

It can be gotten rid of from plants with appropriate treatment if spotted at an early stage, however any buds with WPM need to be disposed of as they probably include lots of more spores than your eyes can see.

Buds ravaged by white powdery mildew!

What are the best ways to prevent, control and treat powdery mildew on your crops?

There are many ways to prevent, control and treat powdery mildew. The most effective way to control PM is to prevent it from spreading. The best ways to do this are:u003cbru003e-Plant resistant strains.u003cbru003e-Keep humidity levels low in your grow area.u003cbru003e-Prevent air circulation in your grow area.

WPM dusting an otherwise healthy plant

What triggers White Powdery Mildew?

High Humidity

  • WPM requires wetness to prosper, however that does not always suggest it requires water. Having a grow location with high humidity is all WPM requires to get going. This appears to be a bit troublesome given that young marijuana plants grow finest in reasonably damp environments (40% -60% RH). Thankfully, high humidity typically just ends up being a concern when it’s integrated with the next cause (low/no air flow).
  • Individuals who reside in environments with incredibly high humidity (such as the southern United States or throughout the UK) can buy a dehumidifier to manage humidity in the grow location. This is particularly crucial throughout the blooming stage when humidity requires to be much lower (45% rh) to avoid widespread development of WPM and bud mold.

Low/No Air Flow

  • White Powdery Mildew has a tough time settling in a grow space where the air is being moved. High humidity will provide WPM the conditions it requires to make it through, however bad air flow is what provides it the capability to settle in the very first location. In truth, a little (ideally oscillating) fan moving air in a grow location will avoid the large bulk of White Powdery Mildew issues.

Poor Ventilation

  • If you have WPM spores in your grow location and the air in grow location is never ever exchanged for fresh air, the spores get several possibilities to arrive on your plants and replicate. This takes place usually in conditions where marijuana is being grown in a closed, unventilated area such as a closet and preventative measures aren’t required to exchange old stagnant air for brand-new fresh air.

Leaf-on-Leaf Contact

  • Leaves that are touching each other will form wetness in between them, and hence they end up being most likely to contract WPM. Inexperienced bushy/leafy plants with great deals of brand-new vegetative development are particularly vulnerable given that they will frequently have their leaves mashed up versus each other as they attempt to reach towards the light.
  • Advanced growers can defoliate a few of the fan leaves that are totally shaded from the grow light to make less option landing areas for White Powdery Mildew. Likewise, defoliation maximizes energy for the plant to utilize when done properly and increases yields! See our post on defoliation for more information.
White powdery mold on the stem of an outdoor plant - White powdery mold can grow nearly anywhere on the plant that's exposed to air.

How to Remove White Powdery Mildew

As I discussed previously, I just recently had a fight with White Powdery Mildew. Rather, it may have actually been a fight if I observed it later on or waited to repair the issue. That’s the one good idea about WPM: in many cases when WPM is captured early, you can eliminate all traces of the mildew without hurting your plants.

There are numerous items and homemade mixtures individuals utilize to deal with WPM. Amongst the reliable treatments are:

  • Milk (1:9 ratio of milk to water)
  • Sodium bicarbonate (2 tablespoons per gallon of water)
  • Neem Oil(4 teaspoons per gallon of water)
  • Hydrogen Peroxide (1 teaspoon of 35% H202 per gallon of water)
  • SM-90(1:5 ratio of SM-90 to water)

Instead of enter into these approaches, I’m going to provide you the basic method I utilize that eliminates White Powdery Mildew on the very first shot, whenever! Here’s my relied on 3-Step White Powdery Mold remedy:

  1. Eliminate White Powdery Mildew from leaves: Get some water (faucet water works fine) and some paper towels. Wet the paper towels and utilize them to carefully clean the mildew off the impacted leaves whilst taking care not to scramble any leaves with spores on them. Utilizing a damp fabric will make sure that more spores stay with the fabric rather of ending up being air-borne. Keep in mind: While it isn’t essential to utilize paper towels, their disposability assists to suppress the spread of spores from one leaf to another.
  2. Ensure plants have appropriate air flow and ventilation: Even if you have definitely no air flow or ventilation in your grow space, having simply 2 fans will considerably decrease your possibilities of coming across WPM while likewise benefitting your plant’s general health. One fan needs to be oscillating if possible and need to carefully blow air over your plants. All the plants require suffices air to carefully rustle their leaves which will make it hard for WPM to settle. The 2nd fan needs to remain in your grow space pointing outside to exchange old air with fresh air. Having a fan explaining of your grow space will require old air out of the space, and in turn, pull brand-new air into the space. At this moment, you’ll have brand-new air can be found in, being utilized and distributed, then tossed out. Bear in mind that 2 fans is a minimum.
  3. Deal with the contaminated plant with among the alternatives listed below to eliminate spores avoid future development: Blend your treatment of option in a tidy sprayer/mister. We advise Lost Coast Plant Therapy(1oz/2btsp per gallon of water) or GrowSafe (2oz/4tbsp per gallon of water) as a safe 2nd alternative. Make certain to speak with the directions on your treatment of option to discover the advised dose. Wait up until prior to your lights for off for the day and mist your (freshly cleaned up) plants. Get all the leaves even if you do not see WPM on them!
White Powdery Mold: Ruiner of beautiful plants.

If you’re growing cannabis, you might want to keep an eye out for White Powdery Mildew. This plant illness can be tough to deal with, but following these simple tips can help you avoid it altogether. First and foremost, be sure to keep your cannabis plants healthy by providing them plenty of light and water. If you do encounter White Powdery Mildew, follow these steps to get rid of it: treat the affected plants with a fungicide, water them well, and then protect them from further exposure to the sun. Keep in mind that this is only a basic guide, so if you have any further questions, be sure to reach out to a cannabis grower or a cannabis dispensary for more advice.