Hot Water and Fungus Gnats

[yesum]

Few drops of liquid soap in a gallon of water will kill the larvae as well. Dries them out I think. Cheap way.

I grow in my home and now make a habit of killing flying gnats anytime I see them. Clap your hands together method, after a while you get good at it. I do not have a problem now as there are never any gnats to begin with or just a few and they do not last.

Can not believe you do not have dunks there in your gardening section. Might be called something else? If you ever get the dunks break them into quarters and let a section sit in water for a day before watering with it. It absorbs into the water and will get down into the bottom of the soil that way.

You can reuse the piece of dunk and keep doing it, make sure all the soil is saturated.

 

[Aussie-Soil]

After days of searching and frustration, the simple answer is aus is fucked. To buy BTI i must purchas it in 5kg amounts (215 bucks), I must Also use my commercial chemical licence to buy it. It would appere BTI is a controlled substance in australia.

I think ill order some gnatrol via the internet. Atm I'm using neem oil soaks to dunk and spray. If it doesn't kill them at least its helping.

 

[RB56]

In that case, ongoing prevention is going to be key. I grow in soil and treat every pot the same. Fiberglass mesh is an important tool for me. I have squares cut for the bottoms each pot size I use. All of my pots have 4 drain holes. The mesh squares have sides equal in length to the diameter of the round pot bottoms. The corners cover the holes. This makes it difficult for adults to lay eggs in the soil mix at the drain holes.

I also have mesh circles, slit to just past the center. Same diameter as the top surface of the soil mix. The slit lets me position the mesh disc with the stem poking through. I cover the top surface mesh with an inch of pea gravel.

All of this makes it harder for pests to move from plant/room to soil and back. That movement is critical for gnats, root aphids and many other plant pests. It has the nice side benefit of stopping soil mix from falling through the drain holes. Since I hand water, the pea gravel and top mesh act as a mulch and spread the water out. Watering now takes very little time and I don't get any wash out.

I'm reluctant to use medium drying as a control measure. Even though I grow in soil, actually 2/3 Happy Frog and 1/3 perlite, I look at it as a hydroponic system - the soil mix provides nutrient "buffering", a little stability if I don't get things exactly right. Since the 5 gallon buckets I use don't have enough nutrients to take the plant to harvest, dry time is hungry time and I don't want that.

 

[Storm Shadow]

Spirotetramat

say adios buggies

 

[mr bub]

is your plant still alive after being doused with boiling water?

 

[BigBudBill]

I too had gnats and here is my experience:

I bought Dunks and sprinkled on top of the soil and water like some have suggested. This didnt work. I was providing the adults with moisture they needed for their life cycle all over the top layer all while not using enough Dunk. It also caused me to over water in attempts to get enough BT in the soil to do its thing. SO...

I tried DE. The DE worked to a limited extent, but the gnats are resilient. 2 observations at this point: 1) a few seemed to "attack" me, in my face every time. Most of them however would try to get back to soil, about half went to the holes on the bottom of the pots. 2) I move my pots, this movement caused adults to come out of the bottom holes and fly out of the top layer of soil.

The DE gums up when watering it. However there is a condition that can be achieved when the top layer dries out and the DE is mixed in(about top 1") that causes the DE to puff up like little explosions when you stir that top layer. I have always stirred the top layer a bit for root development. Not sure if it works but an old lady farmer showed me the technique on my veggies and I always do it. I read that the adults lay the eggs up there and disturbing their life-cycle helped reduce their numbers. SO....

Some things occurred to me while working on this pesticide free method of eliminating the gnats.
1. The bottom holes must be covered in order to prevent adults from enetering soil without passing through DE.
2. Adults that made it through the top layer with DE were now white(covered with DE) and going to die. I still slap them anyways, as I dont want a single egg laid, if I can help it.
3. Assume every adult will lay 10,000 eggs. Always. This will get your mindset to the point of total elimination.
4. Dunks should be used as meant, so I broke them up and let them set overnight in RO water.
5. VERY IMPORTANT. I water with a funnel. I stick the funnel in the soil about 1" and use it to get water to the roots without saturating the top layer, which is important to keep the DE from gumming up. When DE gums up it doesnt work. I use Safer's brand. I mix a few cups in my mix. I have a condiment bottle I cut a bit larger hole in the cap. I spread the DE on top of DRY SOIL. I mix it in. I put more on top of each new pot during each phase from Solo cup to final pot. Every pot has duct tape on the bottom holes. FORCE THE ADULTS TO GO THROUGH DRY DE TO DO ANYTHING. I still water in a drip pan, so I dont have a mess when some leaks out. I also move the funnel to 2-3 different spots to make sure I dont have to many dry zones in the roots.
It has been 3 weeks on this strict treatment and I am down from dozens flying around when I move pots to maybe 1 or 2, some days I have gone without seeing a single gnat.

So in summary....DE on top. Keep top dry by using funnel. Stir top soil gently, esp after watering. Mix what little soil got wet with your dry DE soil and let the fan dry it out, maybe 6 hours. Soak Dunks overnight in water to be used. Dont over water. Dont underwater. Cover bottom holes. Kill all adults you can. Move each pot each day. Look on the floor for adults. Stick to it. Got it?

 

[The OrigF/clred]

I too had gnats and here is my experience:

I bought Dunks and sprinkled on top of the soil and water like some have suggested. This didnt work. I was providing the adults with moisture they needed for their life cycle all over the top layer all while not using enough Dunk. It also caused me to over water in attempts to get enough BT in the soil to do its thing. SO...

I tried DE. The DE worked to a limited extent, but the gnats are resilient. 2 observations at this point: 1) a few seemed to "attack" me, in my face every time. Most of them however would try to get back to soil, about half went to the holes on the bottom of the pots. 2) I move my pots, this movement caused adults to come out of the bottom holes and fly out of the top layer of soil.

The DE gums up when watering it. However there is a condition that can be achieved when the top layer dries out and the DE is mixed in(about top 1") that causes the DE to puff up like little explosions when you stir that top layer. I have always stirred the top layer a bit for root development. Not sure if it works but an old lady farmer showed me the technique on my veggies and I always do it. I read that the adults lay the eggs up there and disturbing their life-cycle helped reduce their numbers. SO....

Some things occurred to me while working on this pesticide free method of eliminating the gnats.
1. The bottom holes must be covered in order to prevent adults from enetering soil without passing threw DE.
2. Adults that made it through the top layer with DE were now white(covered with DE) and going to die. I still slap them anyways, as I dont want a single egg laid, if I can help it.
3. Assume every adult will lay 10,000 eggs. Always. This will get your mindset to the point of total elimination.
4. Dunks should be used as meant, so I broke them up and let them set overnight in RO water.
5. VERY IMPORTANT. I water with a funnel. I stick the funnel in the soil about 1" and use it to get water to the roots without saturating the top layer, which is important to keep the DE from gumming up. When DE gums up it doesnt work. I use Safer's brand. I mix a few cups in my mix. I have a condiment bottle I cut a bit larger hole in the cap. I spread the DE on top of DRY SOIL. I mix it in. I put more on top of each new pot during each phase from Solo cup to final pot. Every pot has duct tape on the bottom holes. FORCE THE ADULTS TO GO THROUGH DRY DE TO DO ANYTHING. I still water in a drip pan, so I dont have a mess when some leaks out. I also move the funnel to 2-3 different spots to make sure I dont have to many dry zones in the roots.
It has been 3 weeks on this strict treatment and I am down from dozens flying around when I move pots to maybe 1 or 2, some days I have gone without seeing a single gnat.

So in summary....DE on top. Keep top dry by using funnel. Stir top soil gently, esp after watering. Mix what little soil got wet with your dry DE soil and let the fan dry it out, maybe 6 hours. Soak Dunks overnight in water to be used. Dont over water. Dont underwater. Cover bottom holes. Kill all adults you can. Move each pot each day. Look on the floor for adults. Stick to it. Got it?

your experience almost mirrors to a T my bud's, from using the dunks on (including the flying into your face to attack - i hadn't thought of it like that but looking back, that is what it was) - for the hey of it, try what i suggested up above, about sprinkling some in a paper plate and leaving it near the pots - there is a bait compound in safer's de, but the part that worried my bud, was the 22% of the compound that Safer said was proprietary and wouldn't identify - didn't like not knowing what was running down into the rootzone. Other vendors or suppliers do label their DE as food grade, but safer didn't - but they did recommend it for veg garden use - it left him a little concerned

my bud ended up using some fine steel wool (#000) over the drain openings - that seemed to work real well but on the soil up top, it turns to a gooey brown mess fast

something else i just remembered we did - someone had suggested a heavy watering with a tobacco tea - i had some cheap pipe tobacco ($11/lb) and we boiled a couple qts of water with a big fist of tobacco. Holy shit, within seconds of watering the plants with it, the white larvae were coming out of the soil and wiggling like crazy to get away from it - in case that helps

 

[ozzieAI]

hey aussie...yates have dipel that is bti...bunnings has it..

make sure you use pure neem oil and you should be fine...neem cake is excellent for keeping FG out of your grow...

 

[kwikness]

5. VERY IMPORTANT. I water with a funnel. I stick the funnel in the soil about 1" and use it to get water to the roots without saturating the top layer

This. Very clever.

 

[Mystic Funk]

just get some beneficial nematodes. on ebay!

gnats reproduce every 3 days. so you would have to pour boiling water on your plants every three days and I don't think plant would survive that lol.