Whats the best way to get rid of fungus gnats?

I disagree ! Not that it’s ever happened to me but there’s growing mediums out there at nurseries, grow shops,or big box stores that have FG in them already before one even purchases it, so one might be fighting an uphill battle before the mix hits the pot! I’m sure others here can verify to this statement! Any others want to pipe in here?

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I am using fox farms ocean forest organic soil I have read online that most soils contain FG I don’t think I am over watering the plants look fine and wen I do water I am only using a small amount I am not filling the pot I am going to give them a dry period of at least 7 days then with try watering from the bottom I have covered the top of soil with diatomaceous earth and before that I had Watered with BTI water

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Checked on plants this morning spotted wot looked like a tiny white or grey coloured fly crawling across top of soil caught it and killed it I had covered top of soil with diatomaceous earth and this little fucker didn’t seem to affected by it as it was just crawling about in it

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The D.E. is a slow kill, it works by scraping up insects shells (exoskeleton) or “skin” then they lose their fuids and die. It’s not like spraying a product (bug spray-raid) be patient.

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Ya what @Uncle_Al said a “Nightmare on Elmstreet” scenario works by dissication Lol!

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3 posts were merged into an existing topic: Humidity control

agree, I think “letting the soil dry out” is bad advice for gnats, they don’t seem to care if the soil gets dry or not, only Bti kills them in my garden. If you let the soil get dry enough to kill them your plants are dead.

FG’s are a normal part of organic growing. I see them every single time. A few waterings with Gnatrol after transplanting eliminates them or reduces them to insignificant numbers. Nemotodes work too but you need to apply them every time you transplant or mix soil which is expensive.

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Ya you’re right, I guess just telling people to dry their pots out is bad advice.
For me tho, pots that ALWAYS stay wet on the surface and grow algae as a result, are breeding-factories for fungus gnats. So I let the top few inches (of a 2 gal.) dry out every few days. (I also use BT and nematodes weekly tho)

The greenhouse I work at is a different story tho. Algae and gnats on almost everything because they water too much. Then they spray poison for gnats lol.

1 easy gnat inhibitor is: Cover the tops of your pots with something. Lids, or 2" of hydroton pellets…

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the problem is “drying out” can mean anything. I also wait to water until the top surface of the soil is dry & crispy. But that doesn’t seem to stop the gnats at all. They’re still scurrying around & doing their gnat bullshit! :smile:

if you wait till the top soil surface is totally dry and dust with D-earth it works great, you can see the little bastards flailing around & trying to escape and dying, they absolutely hate the D-earth. But then I need to water the next day and the d-earth stops working.

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I’v even went as far as putting a 1/2 inch layer of sand on top of the surface which I believe helps deter them I don’t think they can dig very well!

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Almost every time I use any soiless mix like promix or sunshine mix it always contains fn, or white flys, something. So, I would disagree, if it were hydro like rockwool or clay pebbles, and you have fg, yea, your fault.

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Sunshine mix is on my never again list, I have bought exactly one bag that was supposed to be organic and no nutes added. My plants began to develop nute burn and I discovered those little time release pills all through it.

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I just bought a few bales of this, my new organic base mix, supposedly pro-mix is very “cool”:

http://www.pthorticulture.com/en/products/pro-mix-mp-mycorrhizae-organik/

they’ve been sitting outside this summer at the store, I’m sure they’ll have some gnats.

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Are you talking about mosquito dunks or bits? I got lost…

he’s talking starter “charge” of fertilizer in the soil mix. It’s usually chicken “guano” in the organic mixes.

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Actually I’m speaking of neither of those, these pills are maybe 1 or 2 mm in diameter there is one type that goes by the name of osmocote. They are dry usually inorganic chemical fertilizer with a dissolvable time release coating you will find them in all potting mixes that say feeds for"X" months

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A picture of a few of the actual pills or balls I am speaking of

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they’re definitely not supposed to be in organic soil! Yuck. I notice that all the potted plants I buy from nurseries come with Osmocote pellets, seems like the industry standard.

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imagine if the potting mixes came filled with cannabis seeds instead! That’s a business opportunity for a soil company …

They are not supposed to be in organic certified products either, but there they are.


This is the offending product the only bag I purchased.

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