Root Gnats

I have had root gnats as long as I can remember. I have opened new bags of commercial potting soil and witnessed a cloud of them exiting the bag. Above ground, they are harmless, except in their capacity to lay eggs. Some say they are near impossible to eracicate. And as aphids, they can be bad news. But I have read that below a tipping point (population wise) they become beneficial. So that shouldn't be hard. I confess I've just ignored them before, but I'm going for population control from now on.What else in our grow rooms might we have a tendency to over-react on?

Root gnats are a sign that the soil is too wet. Overly wet soil can lead to root rot.
Gnats are good for converting dead vegetation into nutrients, pollination and as food for insect predators. Do you want any of that in your grow?

H2O2 will kill the larvae.
I use diatomaceous earth with sticky traps, and water from the bottom till the gnats are gone.

Good luck

Organic soil contains decomposing organic matter (That's what eventually feeds the plant), by way of bacteria, and fungus. Fungus gnats love....... fungus. No way around it. If you want to keep it organic, then natural predators help. If you don't want organic, run it sterile. Anything you add to the soil to sterilize, will also kill off the bacteria and fungus, that feed the plant. It's kinda the reason I switched to coco. I love organic, but I don't like bugs, bacteria, and fungi, growing in my house.

If you're using bottled nutes, run it sterile. You don't really need the microbes then.

I can’t remember a run without a few fungus gnats, they’ve been heavier than normal the last year. Top dressing with fresh ewc and proper watering keeps them in check and an occasional BTI watering if it gets populated. One thing I see growers over react on is falling for advertisers bs. I blame these advertisers for the fabric pot epidemic, I’ve seen way too many grows battling high rh because they watched a YouTube video.

You could try covering the top of the container with a shower cap, like earthbox does. I never had fungus gnats, with one. Bti works really well also, I forgot about that.

another vote for diatamatious earth layer on top of soil to stop them

I soil drench with gnatrol if I get nats

Right now I'm dealing with a few white flies

electricthot12 said:

I have had root gnats as long as I can remember. I have opened new bags of commercial potting soil and witnessed a cloud of them exiting the bag. Above ground, they are harmless, except in their capacity to lay eggs. Some say they are near impossible to eracicate. And as aphids, they can be bad news. But I have read that below a tipping point (population wise) they become beneficial. So that shouldn't be hard. I confess I've just ignored them before, but I'm going for population control from now on.What else in our grow rooms might we have a tendency to over-react on?

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Bmc micro lift 2-3 drops to a gallon of water use this to water your plants in till the eggs and larve are dead.

Your mediums too wet dry it out a bit make it harder on em

I’ve never heard anything good about having fungus gnats. As mentioned above, a few rounds of bmc micro lift will eliminate them. Worked for me last two grows.

big bud man 413 said:

Bmc micro lift 2-3 drops to a gallon of water use this to water your plants in till the eggs and larve are dead.

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Is there a point of toxicity with the BMC microbe lift? I just picked some up the other day and the instructions say something like 6 drops per 100 gallons. 2-3 drops per gallon sounds like something I’d do in my normally well-intentioned spirit of “fuck it, send it”. I tried using mosquito bits but they didn’t seem to do much and the plants don’t seem to like em.

MissinThe90’sStrains said:

Is there a point of toxicity with the BMC microbe lift? I just picked some up the other day and the instructions say something like 6 drops per 100 gallons. 2-3 drops per gallon sounds like something I’d do in my normally well-intentioned spirit of “fuck it, send it”. I tried using mosquito bits but they didn’t seem to do much and the plants don’t seem to like em.

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I used two drops on my first round and one drop after that (per gallon, every other watering, or once a week) for about three weeks and they were gone. They can always return of course, but mine didn’t this time. They were in all the house plants also. Pretty common.

MissinThe90’sStrains said:

Is there a point of toxicity with the BMC microbe lift? I just picked some up the other day and the instructions say something like 6 drops per 100 gallons. 2-3 drops per gallon sounds like something I’d do in my normally well-intentioned spirit of “fuck it, send it”. I tried using mosquito bits but they didn’t seem to do much and the plants don’t seem to like em.

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You won't have any problems man. Just use 2-3 drops in a gallon of water and water your plants with it in till there gone I've done this many times with no problems and it all ways works.

I've been doing super heavy drybacks so I know its not root rot. Gnats can live in pretty dry medium especially if its frequently watered (coco, hydroton etc) and I think they feed on coco coir tbh. I use a lot of organic preventatives for them Dr Bronners Peppermint Castile soap @ 1ml/gal every few days seems to make them fuck off for the most part. I still use lots of sticky traps on each plant but I avoid using the shit that works like Pyrethrins and Spinosad because I learned the plants can uptake it. Athena Ag makes a IPM that they suggest you feed the plants, then soak the rootball with the IPM then a few hours later flush them with nutrient solution again to wash it out. The idea is if you feed the plants water, THEN do the IPM and wash it out the plants dont drink it up.

I had a buddy who got so many fungus gnats in his indoor cherry tomatoes it was just the craziest thing I've ever seen. Had to be at least a couple thousand. Was in an aquarium with straight vermiculite as a medium, weird style. Got weak plants but tons of gnats lol.

I use Fox farm Ocean Forest so I do get a few gnats after the first watering but I also put up a sticky trap with one side of the paper peeled off and it finishes them off within the first few days

It's doubtful they're gone in a few days.

Sticky traps will certainly kill adult gnats but are useless in eliminating them since the larvae are unaffected.

Microbe Lift BMC or mosquitto dunks (BTi bacteria) are 100% effective but takes about a month to break the gnat life-cycle; it stops the larvae from developing.

I use the Summit Responseable Solutions mosquito bits and just water in a TBSP or two (if it's a good size pot) and I reapply once after two - three weeks and indeed the little worms will be done for.
I rarely use the yellow stickies but I've also got a 2800v UV light zapper that'll get your attention when one meets the Maker!
There's a ton of things people use for top "cover" in the pots, perlite, straw, hydrogen, rice hulls - etc.. if the adult gnats can't get into the soil/coco they are unable to grunt out the eggs in there; that's a win.

I personally don't cover the tops but I also keep BTi at the ready for the first sign of the little scumbags. If I see em flying or the not so subtle "SNAP!!" of the zapper blowing the winged worms into multiple pcs ...
I put the mosquito bits in service and they're gone in 3-4 weeks like Billy the Mountain said. The micro lift is probably more potent than the bits but those work great and I believe either is fine and around $15 or so.

Billy the Mountain said:

It's doubtful they're gone in a few days.

Sticky traps will certainly kill adult gnats but are useless in eliminating them since the larvae are unaffected.

Microbe Lift BMC or mosquitto dunks (BTi bacteria) are 100% effective but takes about a month to break the gnat life-cycle; it stops the larvae from developing.

Click to expand...

Catching the adults is not useless since they lay the eggs that hatch into larvea, it doesn't matter where you break the life cycle as long as it's broken.