Medpot Minstrel: Hydroponics Medical Marijuana

Friday, March 23, 2007


Gray Mold Loves High Humidity

It’s ironic, that only a couple of weeks ago I wrote a blog entry about the importance of good ventilation in your grow room. Soon after, I was trying to be extra diligent and I took apart my fans to oil them. When I reassembled them I must have inadvertently removed the plastic shield on one of the motor wires, which in turn eventually caused a short.

The short blew a circuit breaker on my main power board and normally I would have noticed the fans being off within a few hours and that would have been the end of that. However, I took my family on a three-day hike to celebrate the arrival of spring, so my grow room had absolutely no ventilation from the time the fans went off to when we came home.

As I mentioned in my blog posting, my six ladies continued to transpire (their leaves were releasing the water in the nutrient solution that the roots sucked up) and the humidity in the grow room just went up and up. My 600W High Pressure Sodium light is on another circuit breaker, so it was working properly; controlled by a timer it went on and off every 12-hours like clock work.

The temperature gauge registered the spike in temp and shut the heater off, but the light still generated a lot of heat, which had nowhere to go. So the room was hot and muggy and airless. Very bad conditions for the cannabis plants, but very good conditions for Botrytis cinerea, the fungus that causes Gray Mold.

The first sign of Gray Mold on your cannabis plants is usually the appearance of a white powder, which soon turns gray. This fungus produces grey Mycelium, as well as clusters of colorless or grey Condia, resembling a bunch of grapes, albeit very tiny.

The symptoms of Gray Mold might be invisible, since sometimes this insidious fungus sets up shop deep inside your buds and by the time you notice that the fan leaves have turned yellow, the infestation is full blown.

Infestation is spread by spores that can either fly through the air or travel on water droplets. Avoid misting your cannabis plants for this very reason. Where did the spores come from and how did they enter my grow room? Lack of wise sanitation practices, probably, and lack of caution when entering the room from the outside.

Over eight thousand species of fungi attack plants and 88 of them are especially fond of cannabis. Fungi are actually microscopic plants that do not produce chlorophyll and they are ever present. I’m willing to bet that some are alive on your skin as you read this.

We got home yesterday and as soon as I entered the grow room to check up on my ladies, I felt there was something wrong. The excess heat and humidity hit me in the chest and I frantically started checking my plants.

I had to remove half a dozen buds (best to take them far away from the grow room and burn them) and I sprayed all six plants with a solution of Piranha. This was fighting fire with fire, since Piranha contains live beneficial fungi, including Trichoderma, which are able to fight the Gray Mold fungi.

Ten minutes of troubleshooting enabled me to discover the short in one of the fans and a bit of electrical tape fixed that problem. So my ventilation system was restored and I flushed my nutrient reservoir to make sure and get rid of any Botrytis that might have infected the nutrient solution.

I mixed up a new batch of nutrients, including Sensi Bloom A & B, the root colonizers, the vitamins, and Grandma Enggy’s Humic Acid and Fulvic Acid. I made sure to include Sensi Zym, since the Botrytis fungus likes to hide in plant debris deep in the grow medium.

I also mixed in a generous amount of Barricade, to allow its Potassium Silicate to toughen the cell walls of my ladies in order to ward off any future attacks of pathogens, such as Botrytis.

This week I had to add the first batch of Big Bud and prayed that its supply of building blocks for the bud sites would make the remaining buds big enough and strong enough to withstand bad fungi, bacteria, and other harmful microorganisms.

Next week I’ll spray with Scorpion Juice, in order to restore the induced systemic resistance that was destroyed by the abnormally high humidity in my grow room. You’ve probably noticed that if you have a cold and you go into an overheated, overly humid environment, you immediately get the sniffles and when the heat goes off and you open a window, you very soon feel much better.

I consider myself lucky, since I’ve heard horror stories of Botrytis cinerea wiping out a growers’ entire crop within a matter of days. I have no way of knowing when the circuit breaker was tripped, perhaps the short didn’t happen immediately after we left, but closer to our coming home.

Mold can live on the walls of the grow room, so I wiped every surface with Advanced Nutrients Medical's Wipe Out. I also washed the floor and got rid of any material that could harbor fungal spores.

If you paint the walls of your grow room white, use a fungus resistant paint. Cleanliness and climate control are the keys to preventing Gray Mold, as well as any other fungal infestation.

On top of everything, my CO2 generator was also activated while we were away. This added to the humidity problem. Today, I went and bought a dehumidifier and hooked it up to a humidity-measuring device. In case my fans ever have another short, the dehumidifier will help to get rid of some of the excess moisture from the air.

If this ever happens to you, carefully remove infested buds and any dead leaves. Discard and burn them. Wash your hands thoroughly both before and after handling your plants.

Some people dust with sulphur in order to fight fungal infestation, but this is a dangerous method and extreme caution is advised. Wear a face-mask, you don’t want to breathe in that poisonous chemical.

Gray Mold most often attacks mature flower buds, but it can also harm your stems, leaves, seeds and seedlings. When it attacks seeds and seedlings, it’s called Damping Off. You can read all about Gray Mold on the Advanced Nutrients Medical website, which has articles on all the major diseases and pests that plague cannabis.

Ironically, Botrytis cinerea is the very same fungus that is allowed to slightly rot grapes on the vine in order to produce some highly sweet wines in Europe, such as Sauternes in France, Auslese wines in Germany, and the world-famous Tokay wines of Hungary.

posted by Wes @ 12:08 AM

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