HOW TO GET RID OF FUNGUS GNATS

[budsandtwigs]

Hi all-- For those of you who are tormented by those fungus gnats, I've got a really cheap and effective way to get rid of them without chemicals or toxins. I do quite a bit of indoor/outdoor gardening but in the last 2 years have seen many of my plants killed off by fungus gnats.

I grow patchouli plants as well as trinidad scorpions, bhut jolokias, and others and start them indoors in the usual way. I bought Gnatrol and mosquito dunks this year in anticipation of the gnats but am reluctant to try it for the multiple precautions.

A neighbor recently told me her mother used ground cinnamon to kill fungus gnats and their larvae. I sprinkled some on the soil surface and haven't been bothered by them since. That was 2 days ago with not a gnat in sight. Also, when I lift the pot from the catch tray, there are few dead gnats at the bottom of the tray. Seems like whatever is in the cinnamon kills the gnats, and pretty quickly too. Now I hope to sow my seeds this year in relative peace and less hand-wringing.

Thought I'd pass this along for those with a gnat problem.

[rainbowgardener]

I have had a bunch of these teeny little gnats this year. Other years I've had a few, but this year a lot. I didn't know what they were, but I also did notice losing more plants to damping off (a fungus) this year than in the past and it had occurred to me that the gnats were probably spreading it around. I just didn't know what to do about it, not being willing to spread poisons around. thanks so much!

[budsandtwigs]

It's worth a try with the cinnamon.So far,it hasn't burned any leaves on my plants so that must be a good sign.Another reason why I didn't really want to use chemicals is that I have some medical issues and was concerned about poisoning myself.I kept imagining those little Bt thingys in the Gnatrol and mosquito dunks swimming around to their heart's content in my lungs (a ghastly thought) if I accidently breathed in the dust.I checked my plants this a.m. and still don't see nary a gnat.Thank goodness I finally got rid of those horrid creatures.

[OldThymer]

The cinnamon isn't killing the gnats or their larvae. What is happening is the cinnamon is killing the fungus, which the larvae eat. If the food source dies so does the insect. Cinnamon is just one of many natural fungicides. You can also use chamomile tea, once it is cooled.

[The Helpful Gardener]

BT can only hurt one thing, insects. And it is VERY specific about how; your mosquito dunks only work on the larvae of flies (gnats and mosquitoes being flies); it is var. israelensis. You need a whole different strain to kill larvae of moths or butterflies (BTK, or var. kurstaki) and another to get the larvae of beetles BTSD or var. san diego). This stuff is very specific and harmless for birds, mammals, and you should be drenching it as liquid and not spreading dust anyway...

Cinnamon works on other insects; good to knock down ant trails as well. A very volatile oil though, so I'd be careful about heavy exposure. But please let us know how it turns out. I work out of the pantry more and more these days myself...

HG

[rainbowgardener]

I did try the cinnamon and it did help. Probably would have been better if I had known about it sooner, before infestation got bad. But 24 hrs after sprinkling cinnamon over all the soil, the number of gnats was probably reduced to about 1/3 of what it had been. After 2 days it's now probably about 1/4. Big relief! thanks very much. I will try the chamomile also, it would be a better soil drench, instead of just being mostly on the surface of the soil.

[The Helpful Gardener]

Thanks Old Thymer!

HG

[budsandtwigs]

I did try the cinnamon and it did help. Probably would have been better if I had known about it sooner, before infestation got bad. But 24 hrs after sprinkling cinnamon over all the soil, the number of gnats was probably reduced to about 1/3 of what it had been. After 2 days it's now probably about 1/4. Big relief! thanks very much. I will try the chamomile also, it would be a better soil drench, instead of just being mostly on the surface of the soil.

Same here. Had I known sooner, I probably would have been able to save some of my plants. I'm going to also try the chamomile tea since I hear it's a pretty good form of gnat control. I had to throw out yet another bag of Miracle Gro potting soil/mix since I found the gnats in there. I did some research recently and found there's been some studies on cinnamon oil which they say may be promising for pest control. Seems it's effective against mosquito larvae, which could make it good for fungus gnat larvae. Also, what I did with the ground cinnamon was mixed it in with the soil, then spread a thin layer on top. The mosquito bits will help too since I sprinkle them on top. When the plant is watered, it releases the Bt into the soil.

Let me know how the chamomile works. Thanks.

[Annabelle]

Just thought of this, but one of the problems I had last year was finding bugs under my pots, which I think were aphids (at one point ants were attacking the same area so I think they were attracted to the aphids)

So I'm curious if I put some ground cinnamon in the bottom of the pot (if the pots way deeper than the roots will extend so they don't get a dose of it either)... would that keep them out?

I was also going to chalk circles around the bottom of the pots (on the cement) because I know that keeps ants out - somehow the chalk "confuses" them

[The Helpful Gardener]

So would the cinnamon...

Aphids aren't soil creatures but tend to be found up in the tops of plants, so I doubt it was aphids; bottoms of pots tend to be the domain of sapprophitic feeders (eating decaying dead stuff) like wood lice and worms. Unless you have noted root damage from things like ants getting up into the pots (it can happen), I'd worry more about the tops than the bottoms...

HG

[Annabelle]

Hmm I wonder then what they were... I thought aphids because of the ants... but the ants never went onto the top of the pot just those little buggers below it... they were microscopic so it was hard to see what their bodies looked like, they were swarming just at the hole in the bottom... hmmm

[The Helpful Gardener]

Microscopic swarm at the bottom could be soil mites, which fits everything I said (aphids are bigger). Not plant killers, although there are mites that are. A little light oil deals with mites well...

HG

[ChefRob]

Wherever there is light and nutrients, algae will grow. Algae eat the nutrients you are trying to feed to your plants, and when pieces of algae die they attract fungus gnats. Fungus gnats lead to many other problems.

Some tips that help (dependant upon the plant):

Keep humidity at 50% or lower
Keep heat below 75 F
Don't let stagnant water sit inside any trays
Don't mist the leaves of plants
Apply water directly to soil when it's dry and amend the top inch of soil with a dryer mix
Apply a gentle insecticide to leaves in serious cases

[Selborne]

I joined this forum 5 minutes ago and I've already found some useful info. I'm going to love this place!

[The Helpful Gardener]

CooL Hang around a while Selbourne. Like Jimmy Durante used to say, we've got a million of 'em...

And Anabelle? I've been thinking about it and I think your tiny critters were likely Springtails... pretty common and they like water. Means your soil is healthy; these little guys dissapearing is a first sign of soil pollution. But completely harmless...

G'night Mrs. Calabash; where ever you are...

HG

[rainbowgardener]

Well, HG, you're definitely letting us know what generation you are in. My otherwise well educated 28 yr old son has no idea who Jimmy Durante is (but I do!) !

[The Helpful Gardener]

I'm not old, just well informed...and preserved

Ink...a dinka doo....

HG

[maveriiick]

I didn't read all of the post so i don't know if this was mentioned. But I had persistent fungus gnats and larvae that were finally killed with Neem oil.

I used Dyna-Gro Neem Oil 100% with consisted of one tsp of neem into a quart of water and 1/4 tsp of dish soap. I sprayed the affected plant and also flushed the soil with this combination so that all the soil was drenched, and the gnats were dead within a day.

They thrive in over-moist soils so water less frequently or change soils for quicker drainage. A fan also helps to keep the top soil surface dryer (where the larvae collect and eat away at the plant roots).

http://www.bustan.ca/product_detail.asp ... 33&PID=680

Neem appears to be safe with plants. I've had no ill effects from it use on the plants I've used it on (ficus, sageretia, grewia), but do your due diligence just in case.

[Ely]

I there
I've read some of the notes posted by you guys on GNATs subjects and one that realy made me try is the cinnamon.
I would like to ask those who've experienced with the cinnamon, what do you do with it? Do you boil and after cooling it down you pour it on the top of the soil or do you just mix the powder with the soil? Please I would be very greatfull for your help.

I've got lots of gnats in the house and my partner said that is going to throw my house plants out of the house, only that I love my plants.
I know where the problem started. This spring 2009 I've repoted all my house plants with the Miracle Grow compost and I over watered them and the roots start to roten (most roted). The living room where most my plants are is very dark during the day and very cool in the summer and overwater them didn't helped either.
I've lost a dracaena tree and I've got left with a rubber plant, umbrella tree and orchids. At the end of October I repoted all of them again with more well drain soil because I tend to overwater them and the rubber plant recovered well new leaves come out now, but the umbrella tree seem to loose it leaves. I don't know if it's because doesn't have enough light OR I repoted too late in the winter when the plant goes dormant and no chance of developing roots till spring.

Now, the main issue is the gnats, even though I have changed the soil it seems that there are even more gnats.

Please help.
Thank you

[rainbowgardener]

Yup, just mix the powder with the soil. But you describe perfect gnat conditions -- dark, cool, moist. You are going to have to restrain the overwatering and let your plants dry out between waterings or the cinnamon won't do anything.

If the cinnamon doesn't take care of it the next step up would be treating with Bt (a bacteria that kills the larvae in the soil), yellow sticky traps for the adults, beneficial nematodes, or ultimately pyrethrins (insecticides that are plant derived).

It is the larvae in the soil that damage your plants

Planet Natural and Gardens Alive are two places that sell non-poisonous fungus gnat control products:

http://www.planetnatural.com/site/xdpy/ ... ntrol.html

http://www.gardensalive.com/article.asp?ai=129

But really, stop over watering!

I have had the same experience of getting fungus gnats that came with the Miracle Gro potting soil. Perhaps it would help before we bring the bags in the house to open them up and let the soil dry out some. They pack that stuff moist.

[maveriiick]

But really, stop over watering!

+1

Let the soil dry fairly well between waterings so that maybe the bottom 3rd of the pot could be moist. I would also suggest putting some quick drainage material at the bottom of the pot below the soildto speed up drainage (i.e. hydroton, turface, small rocks/pebbles).

Neem oil works too. I've had 2 prior experiences with Fungus Gnats and this worked both times.

[applestar]

This is a timely reminder with all the containers of plants wintering indoors.

I've mentioned this before, but for some reason known only to themselves, fungus gnats love to go swimming and drown in containers of soapy water.
When I have an outbreak of fungus gnats, I put a small wide mouth container -- re-using cottage cheese containers work well -- of slightly soapy water. I usually use floral scented shampoo bubbles, but it probably doesn't matter what you use, dish soap, whatever (avoid scents that usually repel them like lemon, mint, eucalyptus, etc.) I also make a point of using the vacuum hose to suck up any flying ones around the plants. These two methods work well to diminish the adult population. I love the abovementioned ground cinnamon trick because it smells so lovely. I believe it works to kill the larvae. I also use diatomaceous earth, but DE doesn't seem to work so well on the adult gnats. I've seen them COVERED white and still flying around.

[Ely]

Hi guys, its me again
I've used the cinnamon method and it is working.
Thak you so much for the help.

[The Helpful Gardener]

Good to hear, Ely!

HG

[JasonsIndoorGuide]

One product that works very well on fungus gnats is SM-90. It is a citrus-based product, organic and non-toxic to people and animals.

With many organic gardening methods, it is very difficult to prevent the appearance of fungus gnats. With hydroponics, however, here is the key.....

Algae will grow whenever water, nutrients, and light are present. As individual cells of the algae die, they are naturally decomposed by both micro-organisms and fungus (both present in almost every environment). Unfortunately, fungus is the food source for fungus gnats- and they seem to be able to detect the stuff from miles away, lol.

Once you have some fungus (even a microscopic amount) in your garden, fungus gnats are practically inevitable. So the key to preventing fungus gnats in a hydro setup is to prevent the growth of any algae......

And the key to preventing algae growth is to prevent the light from coming in contact with your nutrient solution......this means using a light-proof nutrient reservoir, using a relatively light-proof hydroponic system, and eliminating spots in your system where the nutrient solution is exposed to light. This is especially a problem with drip systems, where the nutrient solution is dripped onto the surface of rockwool cubes.

For drip systems using rockwool, you will want to use covers on the rockwool and feed the drip emitters underneath the light-proof covers. Otherwise, you are inviting fungus gnats to lay eggs in your rockwool (which leads to larvae chewing holes in your roots)

[The Helpful Gardener]

Try the cinnamon, Jason; probably cheaper and we are getting rave reviews...

HG

[rainbowgardener]

Yup. Last year I had a bad problem with fungus gnats in my seed starting operation, in all the potting soil. I started using the cinnamon after I already had a serious infestation. It helped, but didn't really get rid of them.

This year I started preventatively. I have a pitcher of water that I fill and let sit over night to use for putting water in the trays in the AM. I am keeping cinnamon sticks and chamomile tea bags (another natural anti-fungal) in the water all the time, just replenishing them when they seem pretty depleted. (Fill the pitcher with water as hot as it gets from the tap, to steep the herbs, then let it sit so it is room temp in the AM.) So far zero fungus gnats! And I definitely had some by this time last year.

[maveriiick]

Yup. Last year I had a bad problem with fungus gnats in my seed starting operation, in all the potting soil. I started using the cinnamon after I already had a serious infestation. It helped, but didn't really get rid of them.

This year I started preventatively. I have a pitcher of water that I fill and let sit over night to use for putting water in the trays in the AM. I am keeping cinnamon sticks and chamomile tea bags (another natural anti-fungal) in the water all the time, just replenishing them when they seem pretty depleted. (Fill the pitcher with water as hot as it gets from the tap, to steep the herbs, then let it sit so it is room temp in the AM.) So far zero fungus gnats! And I definitely had some by this time last year.

What is your recipe for each item? i.e. 3 cinnamon sticks in 4 gallons of water? 1 chamomile bag per litre/quart?

[rainbowgardener]

I don't really have a recipe. It's about a half gallon pitcher. I throw a half cinnamon stick and a chamomile tea bag in there and just leave them there for a week or so, until they no longer seem to be "flavoring" the water at all. I have no idea if this is what experts would recommend. But so far it seems to be working. If any fungus gnats show up, I will let people know, but so far still zero.

[The Helpful Gardener]

RBG, have you tried cinnamon just sprinkled on the soil?

[maveriiick]

RBG, have you tried cinnamon just sprinkled on the soil?

I tried it and it didn't seem too work. RBG's method seems more sound as the active ingredient in the cinnamon seems to be fully dispersed in the water. I'm gonna try it.

[The Helpful Gardener]

That's what I was asking after, mav, thanks.

Huh, I have never had to resort to infusions, but it usually doesn't get bad if you sprinkle as soon as you see them. Sounds like the infusion actually cures a bad outbreak... I like the anti-fungal addition too; really good thought (attacking the symbiot algae the gnats bring with them). Barley staw (available as a pond supply) would work there too. Nice idea, RBG.

S

[rainbowgardener]

Last year after I already had the bad infestation, I tried just sprinkling powdered cinnamon on the soil. As noted, it did help, but didn't really eliminate all of them. And since I already had sprouted seedlings at that point, it was hard to sprinkle it on the soil without getting some on the seedling leaves. It seemed to burn some of the baby seedling leaves a bit.

What I'm doing now, I'm doing preventatively. So far, working! And infusing it into the water that is just poured in the tray for bottom watering, I don't risk burning anything.

[The Helpful Gardener]

It is a volatile oil, hence the effectiveness. I'm not entirely surprised about the burn on tender babies (should've warned more; sorry RBG )

And preventative beats curative every time. Nice work, lady.

[applestar]

Definitely jumping on board with the cinnamon/chamomile tea water for the baby seedlings.
Thanks, rainbowgardener!

Now, a question : I'm trying to move away from sterile/dead container soil to a more lively soil mix. What about the more mature plants in larger containers? I make my own container soil mix from home made compost, leaf mold, decayed wood, topsoil, sand, etc. and top/mulch older containers with compost. I encourage at least one earthworm to live in every container. I water with dilute AACT, vermicomposter and bokashi leacheate, mushroom substrate revising soak water, used coffee grounds and teabag soaked water, last swish of juice bottle and milk/sourcream/yogurt container water, etc.

Won't cinnamon/chamomile tea water knock back the built up fungals? Or do you see a more bacterial soil from what I've got so far?

Does an outbreak of fungus gnats indicate things tipping too much into the fungal, so push with more bacterial like bokashi leacheate and dairy container wash water? Go ahead and knock them back with the c/ct water?

I recently sent a baby centipede into the Jalapeno pepper plant container in hopes that it will find gnat maggots tasty.

[The Helpful Gardener]

Easy AS, it's easy to start making assumptions about what is going on in soils based on what we do know, but there are so many complex interactions that it is very difficult, if not down right impossible, to realistically draw conclusions.

All fungus gnats mean is you have wet soil conditions. The bugs bring the rest with them; they "carry" their biological buddies (that green "algae" that I suspect is actually a slime mold) with them. A wet soil tends towards bacterial conditions as oxygen levels drop, so pushing harder could move you out of the ideal ranges for veggies and into the higher bacterial conditions that favor weeds.

Can the antifungal regimens of the chamomile set back fungal culture in your soil? Some I suspect. But there are antifungal aganets llike lactobacillus common in any soil; Trichoderma is an anti-fungal fungus, fer cryin out loud! But these natural fixes have a commonality not shared by chemicals; very low residuals. They break down and dissappear quickly and easily because they alway have. Nature knows how to deal with these because it has always had to. We are finding out that Nature is learning to deal with some of our nonsense as well (witness the polyester eating bacteria), but it has been dealing with the other stuff for millions of years; it's got that down. I suspect you do retard fungal development some, but I doubt you stop it with chamomile and cinnamon.

Our old friends the nematodes are another discussion we should be having here; genus Steinernema to the rescue once again. S. feltiae is a great control for indoor infections, and a natural poop looper as well. If you can't beat them, have somebody else eat them...

HG

[Big Vine]

Just a quick bit of info. from an indoor grower of tropicals for bonsai...
I was plagued with fungus gnats back when I first started out using a heavily peat-based mix (involving typical bagged garden center soil...e.g. 'Miracle Gro').

Fungus gnat populations dropped drastically once I began transitioning to a much more granular/coarse mix. The mix was about 3 parts inorganic (1/8" to 1/4" lava rock) to 1 part organic (peat-based). However, the fungus gnats still seemed to linger.

Fungus gnat populations completely disappeared once I transitioned to my own indoor mix. The mix is 3 parts inorganic (1/8" to 1/4" Florida limestone) to 1 part organic (coconut husk chunks). I should also add that I fertilize at half-strength every time I water (averages about once every other day) with 'Schultz 10-15-10 Plant Food Plus.'


In sum, I have witnessed what appears to be a correlation between the fungus gnats and a peat-based potting media. Of course, I have no scientific trials to prove that this is indeed a direct correlation. Still, it is what it is.
BV

[The Helpful Gardener]

Hydrogen peroxide is another cheap easy fix for this issue; a couple (4-6 oz. of 3% H2O2) in a gallon of water. Water with that. It will set biologies back a bit, but you can wean off as you get control...

HG

[rainbowgardener]

Big Vine - I agree. I do use Miracle-Gro potting soil for starting the seeds and it does have a lot of peat in it. (My main deviation from organic gardening!) I never have trouble with the fungus gnats in my regular containers (house plants, etc) which have a bit of the potting soil, mixed with garden soil and compost.

I think the peat holds too much moisture... I've been advising people against the peat pots for seedlings for that reason, perhaps I need to do away with the potting soil as well. But I haven't found anything else that is fine enough, light enough, nourishing enough for teeny baby seedlings that is reasonably easy for a lazy gardener to do.

I tried making my own potting soil for awhile, but it involved baking compost in the oven to sterilize it (stinky!), buying a bunch of ingredients separately at garden stores, storing stuff, mixing stuff.... more money and more trouble. But I'm open to re-thinking!

[The Helpful Gardener]

Won't get any arguments about using coir over peat from me; makes good sense for that and a number of other reasons...

S