Organic soil and fungus gnat solutions...

[wiesser]

Hey everyone, I'm doing my first run with an all organic soil mix. I'm starting to see some fungus gnats flying around so it's time to take care of these little bastards. In the past I would use "Go Gnats" which i've had great success with, or "Mosquito Dunks", which work great also. Both combined destroy gnats in no time. The problem is now that I'm using an all organic mix, I don't want to damage any of the micro-flora or beneficial life in the soil. Go Gnats claims to be poison, pesticide free, but I've heard mixed things about the ceder oil contained in it and it's effect on organics. The Mosquito Dunks actually say on the package that they are made for organic growing, no pesticides. They have some kind of BT in them, attacks the gnat larva. I think the Dunks are my best bet but I wanted to get some feedback from the IC community. I also just read a post talking about adding crab meal to eliminate gnats, which I will do next crop. Any info on any of these three methods is greatly appreciated!

 

[VerdantGreen]

hi weisser. fungus gnats first and foremost need consistently wet surface soil (or around the holes in the bottom if they can get to them) , so simply letting the top of the soil dry out a bit inbetween waterings will help a lot. i have never felt there is any detriment to a wet/damp cycle in the soil. others might disagree with that. i used to use them as an indicator for my soil staying too wet.

as for additives, BT does work for a while and in itself i havent heard much bad about it RE organics, but the thing that made the big difference for me was using neem meal or neem cake as a soil additive (it has nutrition for the soil too) i hardly ever see any gnats since i started using it in my recycled soil. i add 2-3 grams per litre of soil each cycle, although i may leave it out for a cycle or two now its at a good level in my soil.

gnats arent a huge problem, and it sounds like your first organic run has gone well!

VG

 

[Weird]

DE has served me well in this regard

 

[wiesser]

hi weisser. fungus gnats first and foremost need consistently wet surface soil (or around the holes in the bottom if they can get to them) , so simply letting the top of the soil dry out a bit inbetween waterings will help a lot. i have never felt there is any detriment to a wet/damp cycle in the soil. others might disagree with that. i used to use them as an indicator for my soil staying too wet.

Since I am using a blumat automatic water system the surface of the soil does stay moist, all the time. So letting the soil dry isn't an option right now.

I will defiantly be adding some neem meal to my next run, thanks for the great info VG!

 

[wiesser]

DE has served me well in this regard

My brother, what is DE?

 

[bigshrimp]

I've had success using BT for gnat control, i dont think that it will completely eradicate them. If you use the liquid concentrate make sure that you check the expiration date because it will lose potency. BT will not harm your microlife.

Neem meal and Crab meal are also good choices and make your pots less habitable for them. They take a little while to kick in though.

I suspect that fungus gnats really just love a fresh organic mix. I battles them for my first few cycles but they have disappeared more or less since my mix has aged. I think this is due to increased predation and competition from soil life, and the full decomposition of compost/amendments.

When they got real bad i just got out the shop vac and went to war.

 

[xmobotx]

yeah BTi is a good choice for that & using neem seed meal will control them in your soil mix as well

w/ crab meal, you are relying on the chitinase enzymes populating your mix and that may happen/likely will

neem seed meal has properties to eliminate them whether populations get going or not

 

[Biosynthesis]

Do fungus gnats cause any issues other than being annoying? Ive had them before and they are just a nuisance. Like verdant I just let the soil dry out between waterings and this keeps them in check. This spring the grow room was loaded with the pesky bastards. Left the door open to the grow and several hornets made their way in and ate every one of them. Havent seen them yet.

 

[wiesser]

I've had success using BT for gnat control, i dont think that it will completely eradicate them. If you use the liquid concentrate make sure that you check the expiration date because it will lose potency. BT will not harm your microlife.

Neem meal and Crab meal are also good choices and make your pots less habitable for them. They take a little while to kick in though.

I suspect that fungus gnats really just love a fresh organic mix. I battles them for my first few cycles but they have disappeared more or less since my mix has aged. I think this is due to increased predation and competition from soil life, and the full decomposition of compost/amendments.

When they got real bad i just got out the shop vac and went to war.

I've been using the "mosquito dunks" that contain BT. I crush a little bit up and sprinkle it on top of the soil right under where the blumat is constantly dripping. Keeps it moist. This method works very well, also add a small amount to my res. I eliminated my gnat problem in under 10 ten days using this method. Just wanted to make sure the BT in the dunks won't cause problems with my organic soil. I'm a first timer when it comes to organics. Hopefully I won't have to break out the shop vac!

 

[bigshrimp]

If populations get out of control they can cause damage to roots, especially surface feeders. Can also spread fungal and viral pathogens.

 

[wiesser]

[FONT=Arial, Helvetica, sans-serif]Xmob- Thank you for the straight forward answer. I take that you believe the neem seed meal is the best option?

Biosynth- Yeah they can cause problems, they lay eggs in the soil and the larve feed on the fine root hairs of the plants. Not problems like spider mite problems but they can be detrimental if not dealt with. Didn't know hornets eat the little bastards, my hatred for hornets has just subsided... maybe I can train them like pets, get them on my side, make them do my dirty work for me.....

.... that last sentence was a joke, but after reading it again........ maybe I can use them.............. capture a few, put into freezer, take out of freezer, tie dental floss around the thorax, tie dental floss to bottom of plant stem. Like a pit-bull tied to a tree! Watch gaurds! This may be border-line cruelty but all hornets around my place are dispatched swiftly with no remorse.
[/FONT]

 

[Weird]

Diatomaceous Earth

 

[bigshrimp]

DE is going to shred all your good bugs too...

 

[vapor]

Diatomaceous Earth is the only thing that has gotten rid of those little buggers for me. I add a cup to 20 gal of soil mix in with other amendments and no more gnats, i have used neem seed cake for years and still got gnats. Some of your products{amendments} may have eggs... The DE mixed in the soil works well not on top it just gets hard and crusty.....DE is approximately 86 percent silicon, 5 percent sodium, 2 percent iron and many other trace minerals such as titanium, boron, manganese, copper and zirconium.DE will not hurt earthworms or beneficial soil microorganisms. Diatomaceous earth is one of the few pesticides in the world classified as non-toxic.

 

[wiesser]

So I don't add any beneficial bugs to my mix, but I know that the soil is full of micro-organisms, Vapor and Weird say yeah on the DE but bigshrimp gives it a no. Sounds like we got a little controversy over here.

Bigshrimp- You talking about bugs that you can actually see with the naked eye?

 

[EShred]

Gnatrol is good stuff

 

[wiesser]

Gnatrol in organics?

 

[vapor]

So I don't add any beneficial bugs to my mix, but I know that the soil is full of micro-organisms, Vapor and Weird say yeah on the DE but bigshrimp gives it a no. Sounds like we got a little controversy over here.

Bigshrimp- You talking about bugs that you can actually see with the naked eye?

I think he is saying insects...
I am saying microbes. Imo i would think in organics the microbes would be more help/important then some insects{some good some bad}?

 

[bigshrimp]

Yes im talking microathropods and up. Springtails, mites, roves etc..

Im after a functional ecosystem on all trophic levels, so i wouldn't use it. Your goals may be different.

 

[Tonygreen]

Mosquito dunks work every time for me, complete eradication.