I was wondering if anyone had tips on how to rid soil of fungus nats aka fruit flies
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The top soil on your plant needs to be allowed to dry out. I put nematodes in my soil and treat the plants with Captain Jack’s Dead Bug. Also yellow sticky traps work real well on adult pests.
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Permetherin in a light soil spray usually gets them.
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Fungus gnats are often a symptom of overwatering.
+1 for Capt. Jack’s Deadbug.
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I had this problem with all of my bonsai plants. They love moist soil, so you want to make sure youre not keeping your soil drenched. The only way i was able to get rid of them was adding a thin layer of desert sand on top of the soil, and then some pebbles over that, and Im not sure if that would affect the ph tho.
The key is preventing them access to moist soil though until they die out. They breed like crazy. Outside they have other bugs that prey on them, but inside they are free to keep breeding.
Another thing you can do is buy nemotodes to put in the soil. They are micriscopic organisms that will feed on the larvae if fungus gnats, but im not sure how that would affect mj either. Some options to look into though.
Good luck! They are a pain in the butt. As long as you can keep their numbers in control though, you should be fine. Its when their numbers grow crazy that their larvae can do damage to roots.
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I use yellow sticky traps, works just fine. They like the plants, I run coco so it’s a bit hard to keep them away. But I just place a couple on each plant and they die off. I’ve found if you put them on from the start you won’t see them pop up.
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Mosquito bits soaked in water for 24 hours. Strain and water the plants. Repeat at least weekly. Kills the larvae. And sticky traps for the adults.
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Yellow sticky traps for adults, and put a product called “mosquito bits” on top of your soil, then water over it. Should reapply every so often too. I got rid of a minor infestation this way last year.
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Mosquito bits and yellow sticky traps will take care of fungus gnats, kill the larvae in the medium and reduce the adult population, gotta break the life cycle or they will linger.
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I don’t get them. We do get flies when its dry here. I went to the camping and hiking section at Walmart one day and I saw the yellow tube fly catcher by Repel. They was a $1.97 a month or so ago. They work wonders. I have two at home but I need to change the one in the tent out.
Worth every single penny. The best fly catcher I have ever seen in my lifetime. 
Another for Captains Dead Bug product.
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I’m having a problem with fungus gnats, I had the problem under control with demetrius earth on my already budding plant but my new potted germinated seeds need to stay moist at the surface of the soil. What do I do when the soil on them needs to stay dry? Can I just water the seedlings with a 1:4 ratio of peroxide and water or can I use Demetrius earth even though they haven’t sprouted? Help please.
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I use an eyedropper to water my seedlings. Watering at the base when the seedling first sprouts allows for the tap root to get long.
I use nematodes in my soil. You can also mist the soil with Captain Jack’s Dead Bug. Yellow sticky traps works real well both as traps and an indicator of the level of infestation.
Peroxide will kill even the beneficial bacteria and microbes in the soil. I’ve heard that people flush with H2O2, but I don’t see the sense of it. I definitely wouldn’t expose a seedling to it. Just spread the DE on top and mix it in or add it to some extra soil and then spread it.
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Sounds good thank you.
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I like the idea of using food grade DE on top of the soil. Then add a new top layer of soil. Then add on top more DE. Force them to go through several layers of DE.
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Welcome to the forum @Samuel85 
I mix DE in with my FFHF when filling my pots. Then I use sand on the top of my soil. About two inches of packed play sand with the really large bits sifted out. They can’t go through the sand. It’s a chemical free organic solution and cheap as ****.
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Ok thank you.
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