Fall is approaching for the cannabis/ marijuana harvest. Cultivators have to protect their time, money and energy during this crucial time or the whole harvest could be ruined by mold and mildews. We have witnessed entire crops lost primarily due to green houses with poor ventilation, early precipitation events wetting crops and dehumidifiers that stop functioning when they are left unattended for long periods of time. The following information is a reminder during this phase of outdoor cannabis cultivation. You can refer to this information in the future from our most current Mold & Mildews page.
Botrytis (Grey Mold):
Grey mold is a very common occurrence when cultivating outdoor cannabis annually or when humidity in an indoor environment is not kept in check, grey mold is very easy to identify during flowering stage due to its destruction of flowers and stalks and its distinctive fuzzy grey or black appearance.
Once identified this mold can be treated using 1tsp food grade potassium bi carbonate to 1gal pure water or products such as Green Cure (potassium bi carbonate w/ wetting agent) or Serenade (a type of bacteria that actually eats mold and mildew) There are countless anti fungal treatments available but some of them like Eagle20 are dangerous and should not be used on product intended for consumption!
To prevent infection of plants make sure that you keep the environmental humidity at around 45-50% too much humidity can cause growth of any fungus but in order to spread quickly the spores need to have a dry environment so keep temps and humidity consistent and if you discover a small patch of mold indoors it is best to separate that plant away from other healthy plants and then correct the humidity or treat the room.
PM is something that every gardener has or will have at some point, and once it gets out of control it can become a huge mess!
Fortunately this is a relatively easy issue to cure and prevent.
To identify PM one needs only look as far as the tops of their plants leaves, if you see a thin powdery white coat that can easily be brushed off with your finger this is powdery mildew, once discovered you can treat with the potassium bicarb that we covered in (grey mold) above or you can prevent it using methods such as sulfur burning (indoors and greenhouse) or making sure that your humidity never goes lower than 45 and never higher than 65.