Fungus gnats and coco

Hi all,

On my first grow in soil I had a massive battle with fungus gnats. On this grow 2 weeks in (only one plant), I'm already paranoid about the little buggers coming back but this time I'm growing in 70% coco / 30% perlite. Because i'll be feeding daily in this medium, i'd imagine the soil will be damp most of the time. I'm also going to be using Airpots this time, over standard plastic pots, when she gets to veg. I'm growing in 60cm x 60cm x 160cm tent which is pretty well sealed (one exhaust fan and double-covered the lower vent hole with fine mesh). Is it likely i'll get fungus gnat issues again with the above? I thought I saw one the other day, but none in the tent yet. What other preventative measures can I take to avoid them this time around?

Cheers,
JM

Pictures

I had this exact problem and it was a bitch to deal with. Until I discovered the answer, Mosquito dunks. They're a life saver. They come as little donuts, break it apart a stick a little chunk a few inches into the coco. It's a slow release of bacteria into the medium that kills the gnat larvae. That and just yellow sticky paper to get adults. Good luck.

WintersBones said:

I had this exact problem and it was a bitch to deal with. Until I discovered the answer, Mosquito dunks. They're a life saver. They come as little donuts, break it apart a stick a little chunk a few inches into the coco. It's a slow release of bacteria into the medium that kills the gnat larvae. That and just yellow sticky paper to get adults. Good luck.

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Ah I forgot about these. I shall get some just in case - does anyone happen to know if they are harmful to the final product in terms of ingesting / inhaling? I've already got a load of yellow stickies in there but no adults caught yet, so think i'm okay for now.

Trickyticky said:

Pictures

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They aren't a problem yet, so there's nothing to show! This is asking about preventative measures / first line fixes.

JMystery said:

Ah I forgot about these. I shall get some just in case - does anyone happen to know if they are harmful to the final product in terms of ingesting / inhaling? I've already got a load of yellow stickies in there but no adults caught yet, so think i'm okay for now.



They aren't a problem yet, so there's nothing to show! This is asking about preventative measures / first line fixes.

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Nah it's nothing the plant takes up. Haven't heard of any issues and can't imagine there could be any harm to the plant or users.

I just had a look at the toxicology report on their website and have queried them about an active ingredient which they dont seem to be clear on. Will keep this thread updated if they reply.

JMystery said:

Hi all,

On my first grow in soil I had a massive battle with fungus gnats. On this grow 2 weeks in (only one plant), I'm already paranoid about the little buggers coming back but this time I'm growing in 70% coco / 30% perlite. Because i'll be feeding daily in this medium, i'd imagine the soil will be damp most of the time. I'm also going to be using Airpots this time, over standard plastic pots, when she gets to veg. I'm growing in 60cm x 60cm x 160cm tent which is pretty well sealed (one exhaust fan and double-covered the lower vent hole with fine mesh). Is it likely i'll get fungus gnat issues again with the above? I thought I saw one the other day, but none in the tent yet. What other preventative measures can I take to avoid them this time around?

Cheers,
JM

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Cover your airpots in pantyhose to prevent them from getting in the coco from the sides.........and layer the top with perlite.

Make friends with the gnats is my advice

What he said....Dunks ftw.
Crush and top dress pots.
Drop 1 in your res.

i keep a fan moving air over the top of my coca so the top inch dries out quick. ive not had an issue with gnats ever since doing that i say gnats are telling you your coca is staying wet to much.
im pretty sure most first time grows that use end up having a massive battle with fungus gnats
before starting your next run bleach everything and vacuum even go as fa as taking your lights apart cos ive seen them live inside lone of my old blurple lights

JMystery said:

They aren't a problem yet, so there's nothing to show! This is asking about preventative measures / first line fixes.

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If they aren’t a problem yet yellow stickies.

I had a problem with them on my first grow and the last one was good but this one I had them back. Took the plants outside and sprayed off the larva, coils of sticky paper. I made a little fram to hold the paper flat rather than it coil up so both sides get the buggers. I got rid of them last time by leaving some weeks in between grow, not happening this time so hope to control them.

Thanks for the feedback - yeah, they aren't a problem yet but I can see it coming for sure.

MickFoster said:

Cover your airpots in pantyhose to prevent them from getting in the coco from the sides.........and layer the top with perlite.

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That's genius - I'll definitely be doing that! I did try a top layer of perlite but the gnats here didn't seem to be bothered by it, even when I made it a really thick layer they were still coming and going through it. Little sods.

outsiders said:

i keep a fan moving air over the top of my coca so the top inch dries out quick.

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I think i'll try this too for this grow. Seems logical to (a) dry out the very top layer of soil and (b) make it difficult for them to land.

On my first grow I spent a lot of time with my head in the tent looking at my fine work (lol) but this time it'll be open only briefly for feeding. there's no other way into that tent except for the vent (covered in two layers of mesh) and the exhaust fan (blowing too hard for them to get in that way).

printer said:

I had a problem with them on my first grow and the last one was good but this one I had them back. Took the plants outside and sprayed off the larva, coils of sticky paper. I made a little fram to hold the paper flat rather than it coil up so both sides get the buggers. I got rid of them last time by leaving some weeks in between grow, not happening this time so hope to control them.

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I caught hundreds of them on yellow stickies last time. I think though, they'd already laid eggs before I got them in the tent. This time, they were in the tent before the plant was, and the tent was cleaned out with isopropyl alcohol thoroughly before I started. Bloody hate them - the thought of them makes me feel itchy. I'm also single-handedly responsible for the direct deaths of at least a 100 of them.

outsiders said:

go as fa as taking your lights apart cos ive seen them live inside lone of my old blurple lights

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I switched to Spiderfarm LED this time. That sucker is so thin, there's nowhere for them to hide!

JMystery said:

Thanks for the feedback - yeah, they aren't a problem yet but I can see it coming for sure.



That's genius - I'll definitely be doing that! I did try a top layer of perlite but the gnats here didn't seem to be bothered by it, even when I made it a really thick layer they were still coming and going through it. Little sods.



I think i'll try this too for this grow. Seems logical to (a) dry out the very top layer of soil and (b) make it difficult for them to land.

On my first grow I spent a lot of time with my head in the tent looking at my fine work (lol) but this time it'll be open only briefly for feeding. there's no other way into that tent except for the vent (covered in two layers of mesh) and the exhaust fan (blowing too hard for them to get in that way).

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I would suggest the pantyhose over the pot if your not using regular plastic pots. It will help prevent the gnats from getting through the size. Keeping the top layer dry and putting 2inches of perlite will help reduce the gnats. I also used sticky traps and put them over top of the pot like on top of the perlite and between every pot as well as fly traps hanging. They were gone just as fast as they came

Midwestsmoker419 said:

I also used sticky traps and put them over top of the pot like on top of the perlite and between every pot as well as fly traps hanging.

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In my first grow, I did this too but I think I just did it too late. The stickies actually on top of the pot did catch a load of gnats (on both sides of the paper) but I think by the time I did this, I already had an infestation of them. Mind you, i'd rather that than aphids or other leaf-munchers.

JMystery said:

In my first grow, I did this too but I think I just did it too late. The stickies actually on top of the pot did catch a load of gnats (on both sides of the paper) but I think by the time I did this, I already had an infestation of them. Mind you, i'd rather that than aphids or other leaf-munchers.

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Yes the way I kind of looked at it was by cover the tops of the pots with sticky traps wouldn't allow the larvae that hatch to fly out and prevent older gnats from going back to the soil. I had seen one flying around and went crazy. Most times if you see something there is usually more than one and I didnt want to risk infestation

Just in case anyone was interested, earlier I queried the toxicology report for the Mosquito Dunks with the company who make them and their rep confirms that produce is 100% safe to ingest. His words, not mine. He also said this:

"The insecticidal toxins (in the report) refers to the bi-product of the bacteria that is toxic to the "true flies" or dipterans"

let the plants dry out,i mean bone dry,then cover the top of the soil in pot with either perlite or clay pebbles and have plenty of sticky strips laying around.Its the only way you will get areal idea on how they are doing.But once the plants have dried out give them just enough water to get by.its the reason i love auto pots ,the medium is pretty much dry has a bone,so anything wanting to live in that soil would find it hard .And you not using excessive amounts of water ,any water that is been taken by the plants is been uptake into the growth of plant.Rather than them sat in moist soil or coco for a while.A lot can be learnt from growing in this way ,i learn near enough how much my plants drink daily .Also I know what kinda result I'm gonna get ,from just from how hungry the plants are at the minute there drinking 9 litre of water every 12 hour ,3 plants nothing during lights off .And you also have the water locked off in the res and trays.So cover the medium and also keep anything wet down to a min ,because they can become areal problem.But they are pretty easy to get shut of.I always try to get rid of insects like this naturaly ,i have two of the largest house spiders i have ever seen living in my room.The way you know everything is sound is if you find these dead lack of food.There not spiders that make webs,i normally have ladybirds in my room has well,but found last lot dead .So at minute everything seems OK,I only left Ronnie and reggie the spiders because I just put new clones in there.

I tried controlling watering her but this happened. In coco, she doesn't like being dry even for a short time, and it does dry out quick (2 - 3 days). Gonna need to find another way.