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Gnats best and safest spray for top layer of soil

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Gnats best and safest spray for top layer of soil

marsfan300 31 Replies 3,301 Views
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marsfan300

marsfan300

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#1
Looking for something safe to spray on top layer of foxfarm ocean forest soil to deal with gnats.I know the best thing is to keep the top inch dry but that as we all know isn't always possible and bag soils like ocean forest come with a healthy dose of gnats to begin with.I appreciate any help ty.I have this but it doesn't say gnats .My wife grabbed it randomly just to be a possible help.She doesn't grow so she doesn't know
 

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#3
marsfan300 said:
Looking for something safe to spray on top layer of foxfarm ocean forest soil to deal with gnats.I know the best thing is to keep the top inch dry but that as we all know isn't always possible and bag soils like ocean forest come with a healthy dose of gnats to begin with.I appreciate any help ty.I have this but it doesn't say gnats .My wife grabbed it randomly just to be a possible help.She doesn't grow so she doesn't know
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Ah, yes. It's insect season again. It's one of several challenges when growing during the summer months.

With fungus gnats it's important to consider their life cycle. It's about 17 days. The soil is where the larvae live (and probably the eggs, too). A very light dusting with baking soda misted with a water spray will kill the larvae. Don't let it soak in. That needs to be repeated 5 to 7 days to kill the newly hatched larvae. It works quite well. The only caveat is its high pH, which is about 9.0. That's why to use it lightly. That's not so bad, though, because soils with high organic content tend to become acidic as the organics decompose. I drilled holes in the lid of a jar to use like a saltshaker. Anyway, baking soda effectively kills gnats and is found in most kitchens.

That said, letting the soil dry is the best method, and it doesn't cost a dime.
 
#4
If it has roots and fungus gnats can get to them , they most certainly will invade even a healthy, thriving plant. They introduce the fungus to kill the roots wherever they lay eggs to provide food for them when they hatch. Soil that stays wet is their preferred habitat but any plant is fair game. If the plant is in a pot with drainage holes they will access the roots that way too.

There are much better options than baking soda. First is tightening up your watering game. If your soil stays wet you'll end up with bigger problems than just gnats. Letting your soil go thru complete wet/dry cycles will discouraged them and be better for your plants.

Where I live fungus gnats are everywhere. They're more of a nuisance really. Anything that's basically just stinky water like that Dr. Earth type product or neem oil just drives them away until the stench dissipates. They will fly up into the canopy or nearby but before long they come right back. I've tried diatomaceous earth, amended with neem seed, you name it. IME biologicals are the way to go. I apply BTi to the soil along with fungus fighting bacteria and trichoderma. If they show up and try to get at my plants I don't give them a second thought. They can try but won't succeed.
 
#6
I put sticky-paper things in, it grabs so many adults if you keep up with them that the population nosedives to zero. Total war? Net bag the plants and take them outside, wipe the whole tent with alcohol then water, sticky paper, little tuna tin of half borax and half sugar just left alone in the bottom of the tent, diatomacious earth over coffee filter material covering soil for 3 days then remove all filter paper and DE.
*I'm on plants #4 and 5* So not an expert.
 
#7
ChairmanFester said:
I put sticky-paper things in, it grabs so many adults if you keep up with them that the population nosedives to zero. Total war? Net bag the plants and take them outside, wipe the whole tent with alcohol then water, sticky paper, little tuna tin of half borax and half sugar just left alone in the bottom of the tent, diatomacious earth over coffee filter material covering soil for 3 days then remove all filter paper and DE.
*I'm on plants #4 and 5* So not an expert.
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Thanks !
 
#9
I've never found the sticky paper to be effective. At best, it's a way to detect the presence of gnats. It doesn't get them all. Once I learned to let the soil dry, gnats haven't been a problem.

The pH of baking soda isn't necessarily a problem. It's an effective method to quickly raise the pH of soil. From what I've read about managing pH, however, it is a short-term pH fix, unlike other methods.
 
#13
Someone else mentioned mosquito bits. Good thing to incorporate if it's a lingering problem. The mosquito bits are like spinosad and BT. Harmless to you, your pets and your plant but a deadly bacteria to mosquitoes, and it also works pretty well on the gnats.

I've got a gutter for the condensation runoff of our central air that pools up and I use dunks to keep it from becoming a breeding ground. Don't need it for my cannabis here. The top half inch of soil is usually dry by the afternoon of a watering.
 
#15
Ninjadogma said:
👍👍👍 and you get a little extra side benefit from the silica when DE is used right
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Neem meal kelp meal with DE top dressing otherwise I use bt, spinosad or just peroxide, soap, iso alcohol 1 to 9 then respray with bacillus, soil regularly gets healthy dose of various bacillus as well but I guess im a all or nothing type
 
#16
ken81 said:
Neem meal kelp meal with DE top dressing otherwise I use bt, spinosad or just peroxide, soap, iso alcohol 1 to 9 then respray with bacillus, soil regularly gets healthy dose of various bacillus as well but I guess im a all or nothing type
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After veg I'll only use peroxide soap no neems, various bacillus in soil, they get a pretty healthy dose up to bud of bacillus typically a bt for later caterpillars otherwise I stay away from spray if I can usually last resort putting stuff on em budding
 
#18
ken81 said:
After veg I'll only use peroxide soap no neems, various bacillus in soil, they get a pretty healthy dose up to bud of bacillus typically a bt for later caterpillars otherwise I stay away from spray if I can usually last resort putting stuff on em budding
Click to expand...
That’s where Enzymes Komplete and/or Lost Coast Plant Therapy come in really handy. You can use it through the entire cycle. You can still win Cup events with their use.
 
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