Powdery Mildew: Identify, Prevent and Treat White Powdery Mildew on Cannabis: Part 1 – Identification
By Cannabis Chris on Tuesday, August 22, 2017

Powdery Mildew and Growing Cannabis
“Powdery mildew” are the two words no cannabis grower ever wants to hear. If you’ve ever had powdery mildew while growing medical marijuana, you know it is like the herpes of cannabis plant problems and not one you want to have. If you’ve never had powdery mildew on your cannabis crop, then please congratulate yourself and read on for more information on preventing powdery mildew in the future.

If you are currently dealing with powdery mildew on your cannabis plants, have no fear! There are options for treating, and even eliminating white powdery mildew from your grow room or crop.

Let’s start off with some of the basics that we learned from doing research while battling this problem in the past.

What is powdery mildew:
If you are going to diagnose, treat, eliminate or even prevent powdery mildew on your cannabis plants, you have to first know what you are looking for – right?

First off, powdery mildew is considered to be a fungal disease caused by several different species of plant pathogens that thrive in different parts of the world and affect different varieties of plants. Powdery mildew is partially made up of tiny mycelia and spread by microscopic spores which travel mostly by wind and infect other plants once the spores land and later ultimately germinate.

The image above shows a heavily covered leaf that is severely infected with powdery mildew. It looks almost as though the leaf has been coated with white powder that looks similar to flour. While this is a very heavily infected leaf, many times you can spot powdery mildew when it is contained to a very small area and stop it in it’s tracks.

Powdery mildew, or PM as it is often called, is a fungal disease that affects many plants including the cannabis plant. Powdery mildew has many different species and the one that typically affects cannabis, which is cultivated for medical marijuana, is the same as the white powdery mildew species that attacks hops and even hemp in the wild.

Identify Powdery Mildew on Cannabis Plants
The following image shows an early break-out of powdery mildew. In this stage, you have a lot of hope in treating this disease. In this early stage, and even earlier, you can spot the patches of mildew starting to form. By giving your plants a regular visual inspection, you will notice issues before they become too serious.

Spotting powdery mildew in the early stages isn’t always easy. Sometimes all you have is a very small patch hidden in the crevice of a leaf. This is why I like to give a thorough visual inspection regularly and from different angles. By turning your head to the side and looking at the leaves of your cannabis plant from a side-view, you may just save your entire crop by spotting something you wouldn’t have otherwise seen.

Make daily visual inspections to all plants in your grow for the best chance of spotting a problem early. Doing so will help you keep issues like mold, mildew and pests at a minimum when they do show their ugly crop-destroying faces.

Now that we know what powdery mildew is and the signs to look for in our cannabis grow rooms, let’s talk about preventing it, and then treating it if your attempts at preventing powdery mildew fail.

In part 2 – we will discuss powdery mildew prevention methods, as well as treatment options if you do find yourself unlucky enough to catch a case of the PM blues.