Fungus gnats

I noticed a few of these little bastards and have treated with just water and soap. It seemes to have helped. I am ready to begin flowering and was wondering if repotting in different soil would benefit me or cause more problems at this point? I am currently in Fox Farm soil from a bag i just purchased. Any help please!!!

get some neem oil and gnatrol or gnat off put sand on the top 1 inch of the pot to stop the gnats laying eggs, as the gnats lay eggs in the top 3 mm of soil. plants should recover.

DUDE, ONCE AGAIN, DRY YOUR SOIL OUT LIKE A BRICK AND THEY DIE.. K!? K! then water it slowly once you go to water it again... (wait for the leaves to droop a bit, make sure soil is DRY DRY DRY... then slowly give it water.. like a pint or two. then come back later, once it's gotten all in the soil... and add another pint or two, good growiN!

Thanks I will try all those ideas. Would it benefit me to repot before flowering? They are ready to start flowering? Thanks again!

i use this stuff with cedar oil in it . i dry those little shits out then water from the bottom to keep the top dry. then i spray the surface soil with the cedar oil ( its called go gnats)i fought those bastards through three cycles step one is good fresh soil ilearned the hard way the sand works too but they will find a way be diligent and kill those fuckers

gnats have hampered my last three grows. if you get gnats you wont be able to get rid of them. the only option is hydro if you want too continue growing cannabis indoors.

the widowman said:

gnats have hampered my last three grows. if you get gnats you wont be able to get rid of them. the only option is hydro if you want too continue growing cannabis indoors.

Click to expand...

are you sure ? is it impossible to get rid of fungus gnats ?

Slices of raw potato placed on the soils surface (for a while) will attract the larva. Simply replace the infested slices (flush down the toilet?) with fresh ones until no larva are found on the potato slices 2-3 X's in a row. They be gone.

It's a watering thing . . . not allowing the top of your soil to dry out. I've always had a gnat or two around (not really) and they've never done squat. Definitely can be eliminated from any grow.
Fix watering routine. Sand works on the surface, where they lay. I use diatomecious earth on the surface. Same idea, with added security.

charlesweedmore said:

are you sure ? is it impossible to get rid of fungus gnats ?

Click to expand...

no just turn the soil over a coupla times a day and theyll die

Wavels said:

IMO the easiest and most effective way to kill and prevent fungus gnats from breeding in your soil is to simply sprinkle a little bit of Diatomacous Earth on top of your soil.

It causes the little bastards to "bleed out" upon contact .

Click to expand...

Silica gel dust is used the same way. They use it to keep insects from crawling under wood siding shingles on houses. Insects can't go through it without getting dried out. Probably safer to use because you are supposed to be very careful not to breathe the Diatomacous Earth powder at all because it's harmful to humans. I saw Silica dust being applied on a TV show and they didn't even have to use a mask. Might be a safer choice. I guess you would find it in home renovation stores. It's worth a try. Might not work as well as the DE but maybe it will.

Yellow sticky traps are also good to keep the number of adult flies down to a manageable level. They get completely covered with flies but it can't get them all.

If you like apple cider, get some, the real shit with "fresh squeezed apples" as the only ingredient. Put some in a small dish and place the dish on the floor of your grow room or even on the plant pots. Gnats will get stuck in the cider and die. Hit them with the GoNats also to get the larvae, and blue sticky traps work too.

Mosquito dunks in your water res will kill any larvae in the soil also.

HailTheLeaf said:

If you like apple cider, get some, the real shit with "fresh squeezed apples" as the only ingredient. Put some in a small dish and place the dish on the floor of your grow room or even on the plant pots. Gnats will get stuck in the cider and die. Hit them with the GoNats also to get the larvae, and blue sticky traps work too.

Mosquito dunks in your water res will kill any larvae in the soil also.

Click to expand...

Guys- Gnats are the easiest pests to control and eliminate. No chemicals, no sprays and no voodoo rituals needed.

The gnat life cycle consists of adults laying eggs in your moist soil and then the larvae hatching and eating your ROOTS!

Both of my parents are nationally certified master gardeners and they can make anything grow and grow well. One of the tricks I learned from them was... SAND.

You basically add about 1 inch of CLEAN playbox sand (can be bought at the big box reatilers, Home Depot,etc) to the top of ALL your pots soil. Make sure you shake the pot around to distribute to every possible entry point in the top soil.

The silica and quartz crystals in sand are sharp, and they harm both the emerging larvae and adults trying to get into the soil. Leave the sand topped containers like this for at least 1-2 weeks and your gnats should should die off. I have used this method for years with great success.

DE is another way, but the sand method actually works better and doesn't shift the soil PH like DE can.

After the 2 weeks are over you can pour off, let the top sand layer dry out for a few days and then you should be able to pour it off or remove with a shop-vac for reuse later if needed.

Good luck!

Does your plant absorb the DE powder? I read it is not biodegradable and is actually used as a potting medium for bonzai trees. I wonder if it will get sucked up the plant? If it is microscopic razor sharp can it cut roots if it gets down into the soil????

I used DE powder. I gave them a good soaking then sprinkled a layer of DE. Interestingly enough, when I watched them, they looked like they were dancing on the DE. Then they stopped moving. Any gnat that came into contact died.

I am following a regiment I gleened thru other posts. The DE powder stays on top. I will let the pot dry all the way out. This makes them die of thirst if they dont come up and step on the DE. Then, since the DE is dry, I will suck it off the top (no way to get into soil) and replace with another layer of soil.

Another interesting note, I am 2 days into this process. no water, just DE on top soil. I empited my dehumdifier this morning and it spills a little water when you pull the bucket. 4 or 5 winged gnats IMMEDIATELY flew to the edge of the pool of water and began to drink. Yah I squashed them but it looked like they were desparate for water. There is no available H2O for these guys and the tops of soil are dry. So it appears to be working.

Ever gone on a hike and had no water? These guys are hurtin! I think thats awesome cuz they ARE ALL A BUNCH OF STINKIN FREELOADERS!!!!

I had not a huge infestation, but I can tell they stunted the growth. My girls were plumping up nice and then slowed down. The gnat babies eat the roots!

My last stage after complete drying of soil and removing DE is to water the 1st 3 inches with 1 part Hydrogen Peroxide to 4 parts water. Soil should fizzle. This kills baby gnats in soil on contact and does not hurt the plants. It actually benefits them as it releases oxygen into the soil.

does putting a layer of sand effect the abillity to water the plants? or for the plants to absorb nutrients?

Potato slices seem to be one of those things that work mysteriously for some people and not others.

Diatomaceous earth has to be dry in order to work properly. The components of DE do actually get absorbed by plants (silica and mineral oxides), and it can be used as a soil amendment (it will make stems stronger). Along with sand I feel these things make for a big mess on the soil surface and can hinder the ability of the plant roots to breath. DO NOT use any old kind of sand, there is a specific type of sand I've read others recommend and I forget what they call it.

Fungus gnats are not caused by over-watering. While watering too frequently may exacerbate the issue, letting your soil dry out to the point where your plant roots yellow and growth is effected probably does more harm to the plant than the gnats themselves do. The problem is that when a gnat finds it's way to your grow room with your nice organic-matter rich potting mix, and decides to lay hundreds of eggs in said potting mix, a few gnats turn into tens upon tens very quickly. The real problem is that in your grow-room environment there is likely to be absolutely no predation upon the fungus gnats, their eggs, larvae or pupae. Hence the gnat population grows because it is unchecked. The real solution is to introduce predator organisms or other counter measures. Sticky traps only deal with the adults. You need to take care of the eggs and larvae in the soil. One way is Bti (Mosquito Dunks, Gnatrol) which is bacterium that produces a biological toxin which kills only fungus gnats and a very few other species of insect larva. This needs to be re-applied every other week.

The absolute best ways are with beneficial nematodes or, my favorite predator mites like Hypoaspis. Both of these organisms attack not just gnat eggs and larvae but hundreds of other species of pest insects that could find their way into your soil. Hypoaspis has worked best for me and I now keep them in all of my container plants. They turn gnats and other pest insects into fertilizer, aerate the soil surface and shuttle micro-organisms around.

yea i have them. bug strips collecting alot from them. Had to have my windows open for a few weeks because my ac failed. Learning the hard way! They are not too bad, but def stunted my growth. i put a new strip down every week and they are covered. hopefully when i let the soil dry out for a minute they dissapear. They are on my feminized heaband

blazinbj said:

I noticed a few of these little bastards and have treated with just water and soap. It seemes to have helped. I am ready to begin flowering and was wondering if repotting in different soil would benefit me or cause more problems at this point? I am currently in Fox Farm soil from a bag i just purchased. Any help please!!!

Click to expand...

Gnatrol, works good. Spray over top of soil, use as needed. It is a larvacide so it won't kill adult gnats, just the larva. The adults will die naturally and the larvae will be killed off by the gnatrol... circle of life ends. Once they are gone, spray periodically to make sure none come back. Gnats are simple little bastards to kill.

Sprinkle cinnamon on the surface of the soil and water less often. For fungus gnats.