Black flies around and on cannabis plants. What to do?

Black flies around and on cannabis plants. What to do?
Adam Parsons

What to do when you have small black flies in your grow tent and on your plant? Find out what our expert growers think.

Hi there guys and ladies,

Few days ago I noticed little black flies around flying around the grow-tent. I got a bit worried when I realized some of them stick to my young buds. Is this normal? Should I panic? What do I do?


Hi there Diane,

It seems like you’re probably dealing with Fungus Gnats. There is no reason for real panic, but these little flies can certainly be a pain for growers.

Usually they come into the grow room with cheap substrate or settle around the soil when it is continuously wet without proper drying out periods and unfortunately, they will not leave on their own free will.

We would first of all recommend deploying sticky fly traps to find out how severe the infestation is. Meanwhile, try to keep the medium on the dry side for the next couple weeks.

If you still see them coming, possibly you can look for biological solutions such as Bacillus thuringiensis bacteria for example, which should help you get rid the problem within a matter of time. You can usually find products that contain Bacillus thuringiensis (Bt) in your local Home Depot or grow shop.

As for the ones that got stuck to the buds, simply remove them delicately with tweezers. If possible, use a covered light hood, this way the flies that get to close to the light will not be dropping dead on your plants.

We hope you will manage to control the problem with this advice and will be able to save your plants. Let us know how things turn out!

Adam Parsons
Adam Parsons

As a professional cannabis journalist, author, and copywriter, Adam has been writing about all things psychoactive, CBD, and everything in between for a long time. In an ever-changing market, Adam uses his BA (Hons) Multimedia Journalism degree to keep in stride with contemporary research and contributing worthwhile information to all of his projects.