I just made a new discovery that I haven't heard people talking about.
I've been having minor problems with fungus gnats in pretty much all my grows, past I have been using organic bottled nutrients for my grows, and I've always had some minor problems with fungus gnats. I've tried to ward them off with pretty much all the methods found in the books. Some methods like yellow sticky traps have warded off their numbers, but none have killed them off completely.
I'm now experimenting with super soil for the 1st time, and as usual I've had some gnats flying around. I've been using bark mulch throughout this grow (in past grows hydroton). However now I started flowering and had some nutrient deficiencies in week 3 of flowering, so I decided to top dress with some Florganics pre-mixed compost. After about 1,5 weeks the compost has formed a concrete like layer on top of the soil, which seems to be impenetrable to fungus gnats. 100% of my gnats have gone, and I can't see a single fungus gnat flying around.
Amazing! From this day onward, I will always make sure to mix a top dressing of wood bark and compost to prevent gnats in the future.
Hope this post can help anyone who is trying to ward off the gnat attack :)
thanks FM...I just top dressed my outdoor plants with diatomaceous earth for the thrips but will file this in for my indoor grow later this year. Gnats aren’t bothering the cannabis but they are all over the tomatoes...bet it would work there!
Addition: The Florganics compost that I use has palm ashes and powdered oyster shell, I suspect these two are very important to be added into any compost to have the desired effect of reducing pests. As the ashes are what seem to stay on top of the soil, and form the "concrete like" surface.
How does all this stuff on the top impact watering? 1. Do these things change PH? 2. Do these inhibit water penetration into the soil? 3. I just noticed three or four gnats at my early stage of seedling to veg and want to know if I need to treat soil now before transplant (4” pots now) or treat the soil in the 5 gallon pots I’m about to put them into.