fungus gnats on houseplants

anyone have an organic control that I don't have to order by mail.. there are remedies i can buy from Garden supply catalogs..but i'd prefer to not have to if there is another way..they just come back eventually even when i buy it.

now sure how big the pots are or how many pots are affected, but here's a remedy to consider.

submerse the entire pot in water overnight. the fungus gnat larvae all drown. you have to get rid of all the adults so they don't just lay more eggs into your soil again. keeping the potting soil more on the dry side helps a lot. the larvae thrive in overwatered pots.

I know you are asking for non-mail order but....

if that doesn't work, you can mail order predatory nematodes to water into your plants. these will parasitize the larvae and are effective. i get mine from www.hydro-gardens.com and find them very effective. The shipping cost is more than the product cost.

Try to water less often.

Brenda, you've got one right in the pantry I bet.

Got cinnamon?

The volatile oils in cinnamon are damaging to both the insect and the soil organism (that green slime) that it is in symbiosis with. Works great; they will dissappear almost instantly.

Hope that helps...

HG

Seomul and Paul are right; the causal agent for these lil buggers showing up in the first place is too much moisture...

HG

I like the cinnamon approach.  If nothing else, I just like cinnamon. 

So, what else might cinnamon be useful for?

I should say more about "water less":  I usually water my plants a little bit every half an hour until the tiniest bit of water shows up in the dish.  Then I usually go two weeks until I water again.  I have a shamrock that is my indicator plant for when it is time to water again - when it looks on the edge of death, I water all of the plants.

Cinnamon has helped me foil ant infestations both at home and elswhere. Completely breaks their pheromone trails and leaves em confused and wandering; they eventually just pick up their trail in and clear out.

It's amazing how many scientifically and environmentally sound cures I have found in my pantry, just by digging around for info. By contrast, our use of chemicals is poorly tested (if at all), even more poorly controlled, and uses the population as unwitting guinea pigs (I used to wonder if witting guinea pigs would put up with it, but my experience is when you try to explain it to folks, many seem to like the unwitting part; There's the hurdle to jump... )

So given a choice I choose to find ways I think are LESS likely to whack me, my family, or the surrounding biota. And if I can eat it safely, I'd say chances are good I won't hurt anyone else...

HG

We were given a kumquat tree from some friends, they put some soil from their yard in it so it has a lot of clay and doesn't drain properly, so we have a lot of the fungus gnats. Not fun. My husband put a 1" layer of sand on top of the soil and that seems to be helping... He tried bunches of other things that didn't do anything, hopefully the sand keeps working.

helpfulgardener wrote:
(I used to wonder if witting guinea pigs would put up with it, but my experience is when you try to explain it to folks, many seem to like the unwitting part; There's the hurdle to jump... )


HG

I find that too. scary isn't it? many people prefer to remain ignorant. I guess they think it keeps their lives simple, and in their mind, alleviates responsibility for the consequences. 

EXACTLY! As if not knowing is an armor against possible damages!

I just don't get it, Leah...

Jess, sand is the old greenhouse trick for this issue but it is not foolproof, and the slimemold that FGs live with is a most ancient life form for a reason; it is PERSISTANT. Try the cinnamon as well...

HG

helpfulgardener wrote:
Jess, sand is the old greenhouse trick for this issue but it is not foolproof, and the slimemold that FGs live with is a most ancient life form for a reason; it is PERSISTANT. Try the cinnamon as well...

HG

Good to know, I'll tell the houseplant man in the house.

it wasn't an overwatering problem, it was bad potting soil..the last two bags of potting soil i bought had fungus gnats IN IT when i opened it..the little fruit fly like pests flew out and all over my house and laid eggs in my plants..i was sick.

this had happened once before ..same deal..in the potting soil.

i need to find a better source of potting soil for starting my spring plants..i'll try the cinnamon..i tried some insecticidal soap and it helped some..i put the plants in a pail..soaked them with the soap until it poured out the bottom then let them drain well

i only water my plants every 2 weeks unless they show signs of drying out between..i have hundreds of healthy houseplants..but also have lots of little flies bugging me !!! i have a lot of ground cinnamon and it should smell lovely in here soon.

Brenda Groth wrote:
it wasn't an overwatering problem, it was bad potting soil..the last two bags of potting soil i bought had fungus gnats IN IT when i opened it..the little fruit fly like pests flew out and all over my house and laid eggs in my plants..i was sick.

since their life cycle is 4-5 weeks total, maybe you can buy your potting soil 6 weeks in advance, open it outdoors, and let it dry down completely before you bring it inside.

NM Grower wrote:
since their life cycle is 4-5 weeks total, maybe you can buy your potting soil 6 weeks in advance, open it outdoors, and let it dry down completely before you bring it inside.

Might just contaminate the potting soil with knats from outside though. Unless it did dry out completely, but that'd be had in the plastic bag. Could heat it up somehow.

But if you heat it enough to kill gnats, you are killing other biologies, and if not using solar power for heat, are using an additional energy source to accomplish what good production and handling should have.

Conserve energy and effort, and eliminate bad production practices by finding a good supplier...

HG

So it seems like the fungus knats in our house are spreading to other plants. A lot of other plants. So we've been putting cinnamon on all the ones that seem to be affected. How much cinnamon? Is it effective just on the surface, or after watering when it gets washed down. Is it going to hurt any plants (like any varieties anybody knows of that are sensitive to cinnamon)?

They aren't hurting the plants as far as we can see, except the poor kumquat tree is so stressed it can't really handle any extra harm, but they are really irritating.  And we're worried about the ginger my husband just planted, it's just starting out...

We have had no reports of ill effect to plants and we have been doling this cure out for a while to all sorts of plant owners. We've found just a dusting to be an effective curative to both the algal and insect symbiots.

While cinnamon is technically a volatile oil, you will not need anywhere near a plant lethal dosing to be effective...

Scott

Scott Reil wrote:
We have had no reports of ill effect to plants and we have been doling this cure out for a while to all sorts of plant owners. We've found just a dusting to be an effective curative to both the algal and insect symbiots.

While cinnamon is technically a volatile oil, you will not need anywhere near a plant lethal dosing to be effective...

Scott

Great, thanks. It's smelling very exotic lately, and hopefully we'll see improvement. We have so many plants, hopefully the gnats don't get in them all.

A lot nicer than if you used the usual suspects, Jess... 

S

If the cinnamon method doesn't pan out, 4 oz of hydrogen peroxide to 1 gallon of water does the trick.  Mix up a batch & use it every time you water- it won't harm the plants. 

I also grind up those skeeter dunks (which has the right kind of Bt) and throw about a tablespoon in a gallon of water & use that if the infestation is mild.  The bits will stick to the sides, but that's ok- if it dries out, fresh water will reactivate the Bt.  I don't bother cleaning out the gallon containers, I just add more periodically & give it a good shake.

I just got over a tremendous infestation and had to bump up the H2O2 to 6 oz/gallon.  From "play sand" that I was storing beets in.  Unbelievable amounts of fungus gnats.  Totally gross.  But after dumping the crocks & treating the plants for a few weeks, they're all gone now.

http://www.umass.edu/umext/floriculture/fact_sheets/pest_management/fungnat.html

Nice; yeah I can see how that would work. Cool. 

Thanks ned

S

nedwina wrote:
If the cinnamon method doesn't pan out, 4 oz of hydrogen peroxide to 1 gallon of water does the trick.  Mix up a batch & use it every time you water- it won't harm the plants. 

I also grind up those skeeter dunks (which has the right kind of Bt) and throw about a tablespoon in a gallon of water & use that if the infestation is mild.  The bits will stick to the sides, but that's ok- if it dries out, fresh water will reactivate the Bt.  I don't bother cleaning out the gallon containers, I just add more periodically & give it a good shake.

I just got over a tremendous infestation and had to bump up the H2O2 to 6 oz/gallon.  From "play sand" that I was storing beets in.  Unbelievable amounts of fungus gnats.  Totally gross.  But after dumping the crocks & treating the plants for a few weeks, they're all gone now.

http://www.umass.edu/umext/floriculture/fact_sheets/pest_management/fungnat.html

I think the hubby's done that some, but not every time he waters, for fear of hurting the plants, I'll let him know it's safe.

One of my moderators just logged in and told me that for her terrible infestation, which just spinkling was heading back some, but not completely killing off the gnats, has been corralled by a cinnamon/chamomile tea she made (chamomile is a low grade antifungal). She just put cinnamon sticks and tea bags in a jug, kept refilling and changing out the herbs and spices as they seemed to lose efficacy, and watered the soil (not the plants). She is fungus gnat free and swearing by this method...

Another sure fire method is nematodes (Steinernema feltiae being the most effective and best for indoor use on FG's). Predators are always a green fix, and a good link in the poop loop.

S

So long as it's 3% drugstore H2O2, and you keep within the 4-6 oz range per gallon,  it should not harm the plants.  I keep alot of cuttings overwintering under lights in the basement (AB basil & coleus, geraniums, fuchsias etc.) and have a fair amount of standard house plants (plectranthus, ivies, pothos) and have never had a problem.

Be advised though, that it's not a one dose cure all.  You have to keep using it for a few weeks, and after you think they're all gone & stop using the mix, suddenly one or two will show up out of nowhere.  Thankfully H2O2 is cheap and readily available.

I frequently load up on the skeeter dunks in late summer.  They're kinda hard to find midwinter. 

Glad to help.  Good luck.

ETA: (Oops.  This was intended as a reply to Jessica.  My bad.)

Scott Reil wrote:
One of my moderators just logged in and told me that here terrible infestation, that just spinkling was heading back some, but not completely killing off, has been corralled by a cinnamon/chamomile tea she made (chamomile is a low grade antifungal). She just put cinnamon sticks and tea bags in a jug, kept refilling and changing out the herbs and spices as they seemed to lose efficacy, and watered the soil (not the plants). She is fungus gnat free and swearing by this method...

Another sure fire method is nematodes (Steinernema feltiae being the most effective and best for indoor use on FG's). Predators are always a green fix, and a good link in the poop loop.

And I'll keep the cinnamon tea method in mind.  That might be a good use for those stale sticks you find in the back of the cupboard. I looked into the nematodes, but the amounts available & the price were too much for my small area & wallet.  (Same with Gnatrol.  Yow!)

3 of the worse plants were put into the bathtub and shook cinnamon on them and watered it in..watched the confused little bugs not knowing what to do..they wouldn't go back into the plant..just clung to the outside of the pot..which made them easy to kill.

seemed to be working well so i went around with a huge can of cinnamon and shook it into every single houseplant in the house (a lot)..not sure if it killed them all off..but i have a few days yet before they need water and i'll be hauling out the peroxide JUST TO BE SURE..

i hate them things !!! big time..!!!   will report back in a few days or week and let you know..but i think it might work..thanks so much

Glad to help...

S

So if I got this correct, just dust ground cinnamon on to the soil? I also made a garlic spray I was going to use, I guess that won't work for these little buggers? Like Brenda, I loathe these suckers!!!

If the cinnamon dusting isn't effective, a tea of cinnamon and chamomile (to counter the fungal side) should do the trick...

S

Thanks Scott!

ok, i've been using the cinnamon for a while and i've also been putting the peroxide in the water for the last 2 waterings..

the plants are really in poor shape..some are dying..and will probalby get dumped into the compost pile soon..but some are doing ok..i've only noticed a few gnats..flying, and am hoping that the peroxide is doing the trick on those..luckily we had a couple large bottles of peroxide here as hubby had bought them on sale..(he is kinda a hoarder)..and so i've  been using it up..just dump a small amount in the water each time i water..which is about every 2 weeks.

some of the plants went a little too long between waterings so i think that is why they were dying..as i was told i was watering too much..don't think so..just think it came in on the potting soil..(think that will get dumped outside and not used )

I had the same problem and I know I didn't overwater mine, it is indeed the potting soil. Its so hard to find good help now a days!

i thought about taking the potting soil and dumping it into a large bucket and then dumpin a bunch of boiling water into it and slamming the cover on..to steam them babies to death

That sounds like an ace idea, Im way past that though, all of my soil is wrapped around a banana tree and pepper plants

Bagged soil products are a crp shoot. I remember opening a bag of african violet soil I purchased and having it be like popping one of those ammonia poppers under your noe; that bad. That's fertility gassing off from the soil, and poisonous in the interim...

Making your own soil is preferable although more art than science...

S

late to the post. Get some used coffee grounds and put them on top of the soil. Let us know how it works.

the peroxide did seem to work although some of the plants suffered greatly and were disposed of.

i actually did order a bottle of the gnat killer concentrate though to have on hand as they seem to reappear from time to time..

i manage to save a few of my favorite houseplants but most are gone now..wahhhhhh

I've found laying vermiculite on top of indoor potted plants or starts helps reduce the amount of fungus gnats. A inorganic mulching layer prevents new eggs from being laid in the soil.