Mold Gnats

Nullis

Nullis

Moderator
lol... what the heck are you talking about? Are you alright?

Nullis said:
... And how do you suppose you come off to me? Am I cussing at you and calling you names like a child?
Aside from that I guess I don't see what you're on about... so you did your own research, Good for you? Looks like some of the same advice I gave; is the author of that article also a wannabe know it all?

IF you're over-watering, by all means stop - it certainly might help. But over-watering doesn't CAUSE fungus gnats like people seem to think. It is important to realize this if you actually have fungus gnats but do water properly - and this does indeed happen, but if you haven't actually had them or witnessed for yourself where they are capable of laying eggs then how can you have such a huge opinion about it?
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Yah, that was directed at you. Sure looks like I shut up... :roll:
 
CanadianEh

CanadianEh

Active Member
Over watering can cause fungus gnats in soils with the eggs already inside it; that is what we meant.
Mositure hatches the eggs in soils; thats why if you let the soil dry out extremely well between waterings you can avoid
hatching tons of eggs even when infested with light watering and dry periods. (Like MG soils because they dont sterilize)
 
Nullis

Nullis

Moderator
CanadianEh said:
Over watering can cause fungus gnats in soils with the eggs already inside it; that is what we meant.
Mositure hatches the eggs in soils; thats why if you let the soil dry out extremely well between waterings you can avoid
hatching tons of eggs even when infested with light watering and dry periods. (Like MG soils because they dont sterilize)
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Does that really make much sense? If the eggs where there then an adult fungus gnat had to lay them. I disagree that you should let your soil dry out "extremely well" I think that is horrible advice. There always has to be some moisture in soil; especially in organics. If you let your soil get so dry that it hardens up and pulls away from the sides of the container, then when you do water it first pools up on top and then pisses right through down the sides then you are under-watering. Bacteria and fungi, protozoa and nematodes; they all need moisture and above all the plant needs moisture. Bacteria and fungi go dormant when things dry up that much. Plants don't absorb nutrients so well when you let the soil dry out so much. Not to mention that soil really shouldn't be sterilized... it's about manufacturing\storing it in a sealed environment so no eggs get there in the first place.

Over-watering sure as heck can make the problem worse and in that case gnat populations really get out of hand; but under-watering is no solution and it probably isn't even great prevention. Not every grower gets fungus gnats and not every grower that does get fungus gnats is over-watering. Bti is popular in commercial greenhouse production for fungus gnat prevention and control... are those growers over watering their crops, too?

But whatever I am just an asshole wannabe know it all that doesn't know anything. :wall:
 
sniffer

sniffer

Well-Known Member
Nullis said:
If you have an infestation you're going to need to take a few steps to get the populations down considerably.

First step is to just grab a vacuum and suck those little fuckers to a dusty end. Vacuum around the pots, near the soil surface... where ever you see them. It is best to do this while watering. When you flood the soil surface they are going to fly up in an effort to not be drowned; but you'll be waiting there with the vacuum on and the nozzle ready to take them away. If severe you should take an effort to vaccum away as many of the adults as you can.

Pyrethrin as a botanically-derived insecticide that kills on contact and breaks down within several hours, it is no toxic to birds, mammals or amphibians and leaves no toxic residues which is ideal for our purposes. The spray is widely available, again at most home improvement centers. I am pretty sure this is the same stuff as Dr. Doom, only that brand costs more than it should. This is also good for killing adults on the soil surface.


Mosquito Dunks or Bacillus thuringiensis isreali (Bti) is a natural bacterium that produces a larvacide which is toxic only to a handful of species of insect larvae including fungus gnats and mosquitoes. It is widely available in compressed circular pucks under the brand name Mosquito Dunks, sold in most home improvement centers. They also sell Mosquito Bits, which is the same thing and other brand is Gnatrol but these products are usually less available. If you get dunks you use them by soaking in a bucket of water over night and irrigating. This should kill most of the larvae.

Then of course you should have yellow sticky traps around and Safer brand or Gnat-Stix sticky traps in the containers. But it is hard to bring absolute elimination if you have a lot of plants, house plants, etc. Biological controls are really the best.

I recently noticed herds of micro-arthropods (Hypoaspis or predatory mites I suspect) in my organic soil and consequently gnat populations there have dwindled fantastically.
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yes , and use Mosquito Dunks
 
CanadianEh

CanadianEh

Active Member
Nullis said:
Does that really make much sense? If the eggs where there then an adult fungus gnat had to lay them. I disagree that you should let your soil dry out "extremely well" I think that is horrible advice. There always has to be some moisture in soil; especially in organics. If you let your soil get so dry that it hardens up and pulls away from the sides of the container, then when you do water it first pools up on top and then pisses right through down the sides then you are under-watering. Bacteria and fungi, protozoa and nematodes; they all need moisture and above all the plant needs moisture. Bacteria and fungi go dormant when things dry up that much. Plants don't absorb nutrients so well when you let the soil dry out so much. Not to mention that soil really shouldn't be sterilized... it's about manufacturing\storing it in a sealed environment so no eggs get there in the first place.

Over-watering sure as heck can make the problem worse and in that case gnat populations really get out of hand; but under-watering is no solution and it probably isn't even great prevention. Not every grower gets fungus gnats and not every grower that does get fungus gnats is over-watering. Bti is popular in commercial greenhouse production for fungus gnat prevention and control... are those growers over watering their crops, too?

But whatever I am just an asshole wannabe know it all that doesn't know anything. :wall:
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My wording may of been strong; but i wanted to stress that the soil needs to be dryer rather then wet on a more consistent basis to help reduce mass hatchings.
I guess the weed may of made me over dramatic, who knows..

Aside from that its correct advice;
 
Nullis

Nullis

Moderator
CanadianEh said:
Agree, my wording may of been strong; but i wanted to stress that the soil needs to be dryer rather then wet on a more consistent basis to help reduce mass hatchings.
I guess the weed may of made me over dramatic, who knows..

Aside from that, not too bad advice on both our posts.

Cheers dude.
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Nope, don't worry about your wording... this is the internet; we don't always have time to cherry-pick our words and come off super sweetly. If anything my wording is strong and for the same reasons, but so long as we aren't just slinging insults it's all good.

There's a fine line between being the cause of something, or being a contributing/exacerbating factor. And again constant surface moisture/over-watering can certainly contribute to a huge gnat problem; but it just isn't that simple. You can have a gnat problem in conjunction with sound watering practices, you really can. If you have gnats and over-water your problem is probably going to be worse than it otherwise would be but I can say from personal experience that under-watering doesn't solve the problem and under-watering isn't good for the plant either.

Even if you were to bottom feed\water; gnats get in through the drainage holes on the sides and bottom of the container. They might even be able to find another place in your residence to lay eggs which fare well; such as a house plant or maybe even your sink.

The reason why most pest insect problems arise indoors is because of the lack of predation. Aphids, spider mites, you name it; they all have predators in the outside world and that is why we don't encounter so many of them everywhere. Where there are no predators, which usually includes inside your grow room, there is huge opportunity.

Los Muertos said:
Aren't you supposed to water till you get runoff?
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It helps to. Then it is time to water again when the soil gets dry and light, but it still shouldn't be totally dried out. If you wait too long it becomes even more difficult to water properly; water will bead up on top and run down the sides of the container without being absorbed. In that case you would really need to water a little bit, wait and then follow up with the real watering\feeding in about an hour (I do this anyways); and if you have fungus gnats appearing use a couple prevention\control methods like Bti and sticky traps ASAP.
 
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