Fungus Gnats, Desperately searching for answers.

TheWhiteRabbit420

Active Member
Right into Flowering my plant starts to show signs of a Cal/Mag Deficiency. (Rust Spots, Blotches on the leaves)
This started from the bottom of the plant and continued to work it's way up to the tops of the colas.
I tried everything to fix this deficiency / toxicity in my plant.
Then I find out I've had these white larvae crawling around my drip tray, and on the top 2" of soil.
These fuckers are eating my roots. My plant can't absorb nutrients properly and is slowly dying.

SAM_0364.jpg

She was 6 weeks flowering, I ripped her out after I noticed a pupa crawling around the outside of my smart pot.
If there is an infestation growing in the soil I want that plant out and away from the rest of the flowering plants.
With about two weeks left until harvest it wasn't worth trying to figure out a solution or even apply it.

I assume this is common in indoor, organic grows with high humidity.

How many people out there grow or do not grow in these conditions and often notice signs of a cal / mag deficiency or toxicity in early flowering?

There is a lot of unorganized and misleading information spread across different forums.

I believe these pests came from Fox Farm Ocean Forest Soil.
I'm not saying their soil is shit but with the humid conditions and the less than strict feedings, these root sucking pests were able to thrive.

I was trying to be very precise with things at first which helped and hurt in someways. I was water or feeding every other day.
I would water, wait a day, feed, wait a day, water, etc.. The 2" of top soil was dry but the rest was soggy.

If you're reading this you probably already know about the large thread on Fungus Gnats in another forum:

https://www.icmag.com/ic/showthread.php?t=159960

The information you may be looking for is spread across 150 pages of debates and personal experience.

It would be nice if every grower was aware of exactly what to prevent when growing indoors.

Again, this is an Organic Grow so I'm not going to drench my soil is any Home Depot chemical pesticides while in the middle of flowering..

My Theory: If you catch these guys early in the larvae stage, First let the soil dry out. They thrive in dark humid / wet conditions.
Then add some mycorrhizae. I read somewhere that Oregonism XL by Roots Organic Nutrients has the right species that will essentially kill off these root aphids.
Water Less, and maybe use some Neem Oil. Hopefully these guys will be flushed out if they are in small numbers.

I assume larger infestations would require a more aggressive approach but I noticed there was something wrong immediately when the plant was showing these rust spots.
I was able rule out different causes fairly quickly.

I think a complete infestation of the soil and or grow room would just be too late. They are very hard to kill in large numbers. I just don't think it's worth it.
Remove the plants, pot and tray out of the grow room. Start over. I'm going to run boiling water through my smart pot before I use it again. I am not using Ocean Forest anymore and I am going to start adding mycorrhizae to my soil.
 

growingforfun

Well-Known Member
My girl read a tip that putting a fan it the kitchen makes it harder for them to land on food or other surfaces and thus slows them substantially. My plan is more fans at dirt level to fight gnats and the plants love that breeze anyways
 

RockyMtnMan

Well-Known Member
Right into Flowering my plant starts to show signs of a Cal/Mag Deficiency. (Rust Spots, Blotches on the leaves)
This started from the bottom of the plant and continued to work it's way up to the tops of the colas.
I tried everything to fix this deficiency / toxicity in my plant.
Then I find out I've had these white larvae crawling around my drip tray, and on the top 2" of soil.
These fuckers are eating my roots. My plant can't absorb nutrients properly and is slowly dying.

View attachment 2683984

She was 6 weeks flowering, I ripped her out after I noticed a pupa crawling around the outside of my smart pot.
If there is an infestation growing in the soil I want that plant out and away from the rest of the flowering plants.
With about two weeks left until harvest it wasn't worth trying to figure out a solution or even apply it.

I assume this is common in indoor, organic grows with high humidity.

How many people out there grow or do not grow in these conditions and often notice signs of a cal / mag deficiency or toxicity in early flowering?

There is a lot of unorganized and misleading information spread across different forums.

I believe these pests came from Fox Farm Ocean Forest Soil.
I'm not saying their soil is shit but with the humid conditions and the less than strict feedings, these root sucking pests were able to thrive.

I was trying to be very precise with things at first which helped and hurt in someways. I was water or feeding every other day.
I would water, wait a day, feed, wait a day, water, etc.. The 2" of top soil was dry but the rest was soggy.

If you're reading this you probably already know about the large thread on Fungus Gnats in another forum:

https://www.icmag.com/ic/showthread.php?t=159960

The information you may be looking for is spread across 150 pages of debates and personal experience.

It would be nice if every grower was aware of exactly what to prevent when growing indoors.

Again, this is an Organic Grow so I'm not going to drench my soil is any Home Depot chemical pesticides while in the middle of flowering..

My Theory: If you catch these guys early in the larvae stage, First let the soil dry out. They thrive in dark humid / wet conditions.
Then add some mycorrhizae. I read somewhere that Oregonism XL by Roots Organic Nutrients has the right species that will essentially kill off these root aphids.
Water Less, and maybe use some Neem Oil. Hopefully these guys will be flushed out if they are in small numbers.

I assume larger infestations would require a more aggressive approach but I noticed there was something wrong immediately when the plant was showing these rust spots.
I was able rule out different causes fairly quickly.

I think a complete infestation of the soil and or grow room would just be too late. They are very hard to kill in large numbers. I just don't think it's worth it.
Remove the plants, pot and tray out of the grow room. Start over. I'm going to run boiling water through my smart pot before I use it again. I am not using Ocean Forest anymore and I am going to start adding mycorrhizae to my soil.
I have been battling these fuckers for 6 mos.
I did the 1"-2" of sand on the surface and that slowed them for a couple months, but checking your soil for dryness is impossible through the sand, and the added weight of the sand makes it hard to judge dryness that way also.
Plus the sand washes down the sides of the pot with each watering, and you have to push it back to the edges constantly or correct large wash-out divets in the surface of your soil.
in my experience, that method is mostly for managing and controling the infestation, not eliminating it.

I just bought some mosquito dunks and dissolved some in water and watered all my plants with it, both in my veg tent and in my flowering room.
The product consisits of bacterial spores which are consumed by the larvae.
My neighbor used these and says he hasn't seen one in months.
I do believe it comes in the soil, and that is frustrating.
From what I understand, all the manufactureres of these soil mixes have to do is cook the soil to kill any larvae or other creatures.

How many of us have an oven large enough or even the time, to cook our soil?

I am starting to lean towards coco coir for that reason.

I feel your pain!
 

blindbaby

Active Member
i had a smaller version of your problem. i was using an organic soil. i used a decent, organis soil called 'gardener&bloom'. it was real good. but, i allways got free gnats, with every bag!! lol. i used a product called "gognats", cedar oil, and watered in my transplants with this. it helped alot. i added some yellow stickys. this helped more. and now, im using a 'sterilized soil, called promix hp. and i have not seen a gnat since. how about that? the soil is very nice. very light and fluffy. it has NO NUTES in it, so its also good for cuttings, and seedlings. also, to add. since i stopped using "organic" ferts, etc, i have also stopped burning my plants. i had been adding a small amount (not small enough) of bone, and kelp meal to my large planters. my plants got decent burn. i lowered the amount. still burn. i went to non organics. NO BURN. BETTER GROUTH. GREENER. FASTER. just my exp. non of the stuff out there anymore, is "poison". the epa has made sure of that. anyway. i love the new soil, and, i know im the only one adding anything. the only thing in it, is some mycortizae, added AFTER it was sterilized. i hope this helps. just ask for steril soil.
 

burgertime2010

Well-Known Member
Right into Flowering my plant starts to show signs of a Cal/Mag Deficiency. (Rust Spots, Blotches on the leaves) This started from the bottom of the plant and continued to work it's way up to the tops of the colas. I tried everything to fix this deficiency / toxicity in my plant. Then I find out I've had these white larvae crawling around my drip tray, and on the top 2" of soil. These fuckers are eating my roots. My plant can't absorb nutrients properly and is slowly dying. View attachment 2683984 She was 6 weeks flowering, I ripped her out after I noticed a pupa crawling around the outside of my smart pot. If there is an infestation growing in the soil I want that plant out and away from the rest of the flowering plants. With about two weeks left until harvest it wasn't worth trying to figure out a solution or even apply it. I assume this is common in indoor, organic grows with high humidity. How many people out there grow or do not grow in these conditions and often notice signs of a cal / mag deficiency or toxicity in early flowering? There is a lot of unorganized and misleading information spread across different forums. I believe these pests came from Fox Farm Ocean Forest Soil. I'm not saying their soil is shit but with the humid conditions and the less than strict feedings, these root sucking pests were able to thrive. I was trying to be very precise with things at first which helped and hurt in someways. I was water or feeding every other day. I would water, wait a day, feed, wait a day, water, etc.. The 2" of top soil was dry but the rest was soggy. If you're reading this you probably already know about the large thread on Fungus Gnats in another forum: https://www.icmag.com/ic/showthread.php?t=159960 The information you may be looking for is spread across 150 pages of debates and personal experience. It would be nice if every grower was aware of exactly what to prevent when growing indoors. Again, this is an Organic Grow so I'm not going to drench my soil is any Home Depot chemical pesticides while in the middle of flowering.. My Theory: If you catch these guys early in the larvae stage, First let the soil dry out. They thrive in dark humid / wet conditions. Then add some mycorrhizae. I read somewhere that Oregonism XL by Roots Organic Nutrients has the right species that will essentially kill off these root aphids. Water Less, and maybe use some Neem Oil. Hopefully these guys will be flushed out if they are in small numbers. I assume larger infestations would require a more aggressive approach but I noticed there was something wrong immediately when the plant was showing these rust spots. I was able rule out different causes fairly quickly. I think a complete infestation of the soil and or grow room would just be too late. They are very hard to kill in large numbers. I just don't think it's worth it. Remove the plants, pot and tray out of the grow room. Start over. I'm going to run boiling water through my smart pot before I use it again. I am not using Ocean Forest anymore and I am going to start adding mycorrhizae to my soil.
Not a big deal actually, I get them all the time. So, first just relax and I will walk you through it. With 3 weeks left I assume....... it is not too late to use an ovicide (egg killer). I use Gnatrol and reccommend you do as well (bacterial) this disrupts the breeding and kills their 5 day life cycle at its earliest point. You should pick up some liquid kelp extract and depending on the extent of the root damage you might want to pick up some Hydrogen Peroxide and do a root zone conditioning(sterilization). This kills their primary food source and although it destroys beneficials too it rejuvenates the root zone. Do not use it with the gnatrol as it will kill the active bacteria that make it work. Next, if you have a pump sprayer put cinnamon, cayenne, neem, and a surfactant in hot water and spray the soil surface as well as the bottom 1/3 of the plant so long as you are able to avoid misting the flowers.....you dont want the smell is all. This is a very effective repellant as well as a contact killer....all organic. Dr bronners peppermint soap can also be added. So basically, Kill their eggs, their food, repel their return and focus on root zone restoration. I would use Myco, humic acid, kelp...thing of that nature as they are innoculants and they encourage the renewal of old roots. So, now you must deal with with the Ph problems they cause that are locking out nutrients giving you spots and such...If you want more info on that let me klnow. Dont give up.
 

Luscious.Earth

New Member
Out oh, i hope that's not what's going on here... I'm a bit lax on the feeding regimen which I attribute the yellowing to. Bottom leaves are always dying off, but i noticed some rust scabbing on lots of em. I should mention i let them get dry between watering and have a small fan running 24/7, I don't think humidity is an issue. The plants get checked every week or so with a magnifying glass for pre-flower sexing and any problems. Never seen any mites or gnats. These are mostly moms, and i know when you "prune" any plant it causes roots to die off and decay, becoming part of the soil. Would that be mimicking some of the symptoms? I've had fungus fly/gnat problems in house plants before, and haven't seen any white stuff on soil, or the pesky buggers themselves.IMG_2489.jpgIMG_2490.jpgIMG_2492.jpg
 

TheWhiteRabbit420

Active Member
Not a big deal actually, I get them all the time. So, first just relax and I will walk you through it. With 3 weeks left I assume....... it is not too late to use an ovicide (egg killer). I use Gnatrol and reccommend you do as well (bacterial) this disrupts the breeding and kills their 5 day life cycle at its earliest point. You should pick up some liquid kelp extract and depending on the extent of the root damage you might want to pick up some Hydrogen Peroxide and do a root zone conditioning(sterilization). This kills their primary food source and although it destroys beneficials too it rejuvenates the root zone. Do not use it with the gnatrol as it will kill the active bacteria that make it work. Next, if you have a pump sprayer put cinnamon, cayenne, neem, and a surfactant in hot water and spray the soil surface as well as the bottom 1/3 of the plant so long as you are able to avoid misting the flowers.....you dont want the smell is all. This is a very effective repellant as well as a contact killer....all organic. Dr bronners peppermint soap can also be added. So basically, Kill their eggs, their food, repel their return and focus on root zone restoration. I would use Myco, humic acid, kelp...thing of that nature as they are innoculants and they encourage the renewal of old roots. So, now you must deal with with the Ph problems they cause that are locking out nutrients giving you spots and such...If you want more info on that let me klnow. Dont give up.

I gave her some Oregonism XL which has the kelp and mycorrhizae. This will kill their primary food source right?
I will go get a pump sprayer and use the cinnamon, cayenne pepper, and neem oil with hot water.

I already used the beneficial bacteria so I don't want to use the Gnatrol right? Well since the mixture of cinnamon, cayenne and neem oil is a contact killer shouldn't this kill their eggs? But will it also kill the beneficial bacteria?

The PH has been kept around 5.5 with the nutrients from the beginning.. run off is around 6.5
 

TheWhiteRabbit420

Active Member
Out oh, i hope that's not what's going on here... I'm a bit lax on the feeding regimen which I attribute the yellowing to. Bottom leaves are always dying off, but i noticed some rust scabbing on lots of em. I should mention i let them get dry between watering and have a small fan running 24/7, I don't think humidity is an issue. The plants get checked every week or so with a magnifying glass for pre-flower sexing and any problems. Never seen any mites or gnats. These are mostly moms, and i know when you "prune" any plant it causes roots to die off and decay, becoming part of the soil. Would that be mimicking some of the symptoms? I've had fungus fly/gnat problems in house plants before, and haven't seen any white stuff on soil, or the pesky buggers themselves.View attachment 2684105View attachment 2684106View attachment 2684107

I don't think there are any pests eating at your roots. It is always a good to keep checking for them though! Your soil looks dry and mixed well. I can't say exactly what the yellowing is but it doesn't look serious.
 

burgertime2010

Well-Known Member
I gave her some Oregonism XL which has the kelp and mycorrhizae. This will kill their primary food source right? I will go get a pump sprayer and use the cinnamon, cayenne pepper, and neem oil with hot water. I already used the beneficial bacteria so I don't want to use the Gnatrol right? Well since the mixture of cinnamon, cayenne and neem oil is a contact killer shouldn't this kill their eggs? But will it also kill the beneficial bacteria? The PH has been kept around 5.5 with the nutrients from the beginning.. run off is around 6.5
Ok, so the larval form of the gnat feeds on roots and decaying organic matter in the top couple inches of the soil. Essentially, the kelp and myco are rooting stimulants that will help to restore....they are not anti fungal. Since you are so late into flowering dont worry about destroying myco...it is the last of your worries. There is a sequence that you need to do each step in to make this work. The spray mixture is a contact killer for the adult gnat but is not intended for use as a flood. Remember that gnat larvae do nothing but eat and shit, they spread infection and virus and cause PH swings and nutrient issues. First, we kill the underground funk with a peroxide dilution in tap water that is phed. After this runs its course(a few hours later) you are ready for gnatrol application. You have a sterile root zone and the gnatrol will be in full swing within 24 hours. Now the spray is just for the very top of the soil to ward of and kill adults, do not let it saturate the soil. Watch your eyes and lungs too.
 

Pepe le skunk

Well-Known Member
Gnatrol, Nematodes and soaking the bottom drain holes with gnatrol with sand on top of the pots did the trick for me. I also used soap, water and vinegar traps (in plastic dishes) to catch the little flyers. They love the smell of vinegar in the morning! I also cut yellow sticky traps into strips to get them at the top of the soil. Makes the traps work better in my opinion at the soil surface level.
You have to use the gnatrol 3 times over 14 days as a soil soak AND DON'T FORGET TO SOAK THE BOTTOM DRAIN HOLES OR THEY WILL BREED FROM THERE.
 
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