Dave...sounds like fungus gnats.

What type of soil are your plants potted in?

Soil gnats enjoy continuously wet soil, dry/humid, stale, non-moving air.

You can either pot your plants in well-draining soil or make sure soil dries between waterings.

If it's warm outside, crack open a window and run a ceiling or rotating fan.
Before watering, stick a thin stick deep in soil as far as it will go. If the stick comes out wet, withhold watering. When the stick comes out clean, 'an example..baking a cake and inserting a tooth-pick,' clean. lol

If your soil is too heavy, it's better to repot plants in a well-draining mix.

Toni

Dave, sorry you didn't like the info I gave you already, which was very similar. But glad you're here to chat! Hope you find something that works for you and your lettuce.

Certainly fungus gnats. Yes, there is something perfectly safe that you can use when you water your plants. It's called Bacillus thuringiensis Israelensis (Bt-I). It is available as a product called Gnatrol or you can buy a pack of mosquito dunks....the things people put in their ponds to kill mosquito larvae.

Bt-I will kill the little gnat maggots in the potting mix.....which means no more adults emerging after a few weeks.

But the bigger problem IS the quality of your potting medium, watering practices, and other growing conditions. It's possible
to grow plants, even those in moist seedling flats, without seeing the first fungus gnat. I've done it for years, without Gnatrol.

I was plaged with those flies last year and I couldnt get rid of them. No matter how much I left the surface of the soil dry out.I repotted this past spring adding a lot of perlite. This fall so far I dont see any.

purpleinopp, I appreciated your advice very much. I'm just trying two forums to make the most informed decision I can. :-)

I have heard a few things. (1) 1 part rubbing alcohol and 1 pat water in a spray bottle. The alcohol is supposed to kill the bugs but also will evaporate without harming the soil. (2) A lady told me one time to use yellow sticky paper. Which I later found out was a rat trap. I didnt have the bugs crawling in the soil as you do but I had gnats flying around the whole house. I have tried the alcohol and it didnt work for me...but I did change my potting mix and repotted all my plants and they are pretty much gone with one popping up here or there. Its been 2 weeks almost now.

I'll toss my hat in the ring with everyone else who said or suggested an ounce of prevention ...... The best way to find relief is by examining your soil choice and watering habits, then modifying either/both in such a manner that extended periods of soggy soils become a condition associated with the increasingly distant past. I can use the superlative 'best' because in addition to being rid of the gnat issue, which is more an annoyance than a real problem, you get the added benefit of your modifications carrying with them greater potential for a healthier root system, which means greater potential for a healthier plant.

An interesting aside - several weeks ago we had a large number of fungus gnats, drain flies, fruit flies invade our home. At the time, ALL my plants were still outdoors, and I never have a gnat problem anyway; but for some reason, there were dozens of the little buggers in mainly the kitchen and a few in a lower level recreation room. They stayed about 2 days & then simply disappeared - strangest thing.

Al

Tiff, lol, rat traps..Sticky paper rat traps.

Actually, small/yellow sticky traps, work great, trap flying bugs such as whitefly. Been there, done that.

However, I don't know if traps work for gnats..guess if gnats are flying, and trap is attached to the plant, or for those crawling on soil, gnats will end up glued to traps.

Al, is it possible the little flying insects were fruitflys and not gnats? All it takes is a small piece of ripe fruit...
You mention your grandkids visiting? Maybe one of the kiddies dropped a piece of fruit behind the couch or chair, which attracted fruitflys?? Just a thought.

Entirely possible - I mentioned them as one of a trilogy of possible offenders in my post previous, along with drain flies. No kids - no rhyme - no reason - just came & went ...... That it was an idiopathic incident is the only thing that made it notable.

Al

Dave, are you still around? I'd like for you to describe the 'things' you observed crawling around on the surface of the potting soil. Fungus gnat larvae are tiny, whitish-translucent maggots that we usually only see when we water our plants. Once they pupate, their wings are fully operational.

Didn't get a real answer from any of this. I have what is known as fruit flies (possibly gnats) in my lemon tree plants. I would like too know in plain english what I use, how I use it and any watering positive suggestions that work to rid of these and make my plants healthier.

Thank you

Quoted from above & paraphrased:

"You can either pot your plants in well-draining soil or make sure soil dries between waterings.

... Before watering, stick a thin stick deep in soil as far as it will go. If the stick comes out wet, withhold watering. When the stick comes out clean, 'an example..baking a cake and inserting a tooth-pick,' clean. lol ...

If your soil is too heavy, it's better to repot plants in a well-draining mix." [Toni]

These suggestions seem pretty plain English to me.

I think Fruit Flies & Gnats are 2 different things. Do you keep ripening fruit near the plants? Is that where they're coming from?

If you have gnats: Fungus gnats like decay - so wet soil rich in organics will provide the ideal breeding ground for them. Wetter the soil (or stagnant water sitting in saucers), more of them will be around - and actually they indicate that plants are likely over-watered...not good for their roots. So you can take care of the problem (wet conditions) which is the best, or keep trying to eliminate them with yellow sticky traps, BT, slices of raw potatoes sitting on top of soil (+few other techniques)...or chemicals that will also kill beneficials. But that is like covering the problem.

I had them in my giant heart leaf Philo, and they're very obnoxious. I let the soil dry out completely; bone dry. Usually kills them off. I've heard you can do a 50/50 mix of water and Hydrogen Peroxide but I've never personally tried it.

Anything that you treat it with will make your plant inedible. Soak the whole pot in water for 15-20 minutes. The larvae will float to the surface and then scoop them out of the water. Then let the soil dry out between waterings, do not let the soil stay moist or else you will have a repeat. Soil is also very important. If you have soggy soil, you will probably get fungus gnats again and again unless you follow the advice given above.

Better soil, with more drainage, Less watering, let your soil dry out. It doesn't matter what you treat your plant with if you do not curb your watering practices, they will come back.

I have two plants in my home that are infested with these horrible little gnats. I've tried everything apart from repotting. Traps, reduced watering, homemade insecticide, gravel on the topsoil all work, but not enough; i want to kill them all. Gnat genocide is my intention.

I should just repot the plant but it is big and heavy. I've decided to attempt one last shot with the insecticide and then cover the gravel with plastic to see how much they enjoy it.

One last thing. The two plants infected with these flying pests have one thing in common (which I find slightly disturbing), I put my used coffee on the top of the soil. Is it possible that the eggs of these Gnats were in the coffee (yuk!) and managed to survive boiling water? That shouldn't be possible!

Was there sugar in your coffee? I think the gnats are attracted to the sugar rather than your suggestion. Hopefully!!! I also don't think coffee is good for plants.

I think you should put your plants into a fast draining soil. Gnats like wet peaty soil. I have some that fly around a bit but most of my plants are in a bark based soil so I only see a few.

I've heard mosquito dunks workwell but correcting the soil is the best course of action.

Gnats like organic, wet soil. And water standing in saucers. I doubt that they were in coffee grounds, but adding them created more moist environment. Best to have potted plants in well draining soil - as jamila said: ..."correcting the soil is the best course of action"... Using methods you mentioned helps somehow, but does not get rid of them...it would have to be repeated again and again...

Those irritating gnats are what caused me to change the soil I use and I haven't had to worry with them since!!!

Go to your local garden center and buy some Mosquito Bits (or order a small container of them on Amazon). You may have to reapply after two weeks to make sure you get all life cycles of the little brats, but it's the only thing that ever worked for me, and it works REALLY WELL.

Repot and if you find the plant that brought them in get rid of it. I bought a plant from a garage sale that brought them in . Put it out and repotted. All are gone.

Gnats are a symptom of an underlying problem. A wet soil with a rotting organic component. Organic fertilizers also contribute to the issue. Fish emulsion and fertilizers that rely on various meals (horn meal, feather meal, cottonseed meal, .....) as nutrient sources send them into an orgiastic frenzy. Poisoning them, traps, sand/gravel, mosquito dunks ...... all treat the symptom. If you use an appropriate medium and monitor your watering, they'll disappear on their own.

Al

If there's one.....there's a hundred waiting in the soil somewhere. And all it takes is one.

Tapla- it is an underlying problem, but most of the time the origin is the store/grower or bugs are already in the potting mix bag. I guess one could fly into the house when the door is opened and lay eggs in the soil, but that is less likely. When you buy plants, do you treat them before you bring them inside?

I don't use soils someone else made and I don't treat for gnats because the soils I use don't support gnat populations. Makes remaining gnat free easy.

Al

Some of us live in areas where we can only garden indoors, don't have cars (to transport heavy bulk supplies, nor the space for those supplies if we do get them home), and don't have a huge variety of gardening supply choices. We also like to or have to travel, so watering extremely well-draining gritty mix every two days isn't an option. Regardless, we love plants, so we keep trying.

Personally I order Black Gold, Repti Bark, perlite, and charcoal online and mix it into something approximating "jungle mix" (see ExoticRainforest.com) for most tropicals. However, you're all right — the Black Gold is organic and is probably contributing to my own gnat population (I've been waging war for some time).

Repotting everything (dozens of plants, lost count) would be absurd, and I don't even know what soil I could acquire online to replace the BG that isn't Miracle Gro. (Happy to see recommendations.)

Drying out also isn't an option with plants that must be kept moist (certain tropicals, ferns, etc.)

I've found that a slow and steady but unrelenting attack schedule with Neem oil (both water/Bronner's/Dynagro neem spray and adding a bit to watering pitchers) and BTi (Gnatrol, mixed into watering cans) is helping. They're becoming quite stupid: slow, forget to fly, easy to squish. Possibly sounds psychopathic but it's satisfying to see.

I also have on hand: mosquito bits, diatomaceous earth (extremely messy, needs reapplication too often, inhalation danger, limited success), regular pesticide spray from Big Box stores (especially for new plants from outdoor markets and stores; no idea what they might drag in) and 2-sided sticky traps for the adults.

Anyway I've been lurking here and learning for quite a while. Wanted to add my two cents because, while I understand the point of quick-draining mixes and prevention, I've observed a tendency toward a homogenous approach to gardening. It may be the "right way", but again, we don't all have ideal environment/supply/budget situations to work with and I hope that we can learn more about how to deal with the circumstances and supplies we do have access to.

(On budget: some supplies can be very cheap or expensive depending where you live. I've seen recommendations for "cheap" solutions that are less so in areas without easy access to them.)

How much of the Black Gold are you putting in your mix? It sounds like you may be putting too much if its attracting gnats!!!!

If your chemicals are working for you that's fine.

TN - Glads to see you enter the flow! I, for one, absolutely agree there are different strokes for different folks, which is essentially what you said. Repotting (including root pruning) might seem absurd to grower A, but to me it seems absurd not to because of the limitations root congestion presents. Everyone recognizes that not having a car, being able to grow indoors only, the need/want to travel, ..... are issues the grower needs to resolve however he sees fit; however, deciding what seems appropriate to the grower doesn't change the impact those decisions have on the plant. My discussions are always (well, almost always) from the perspective of the plant because I figure people are smart enough to weigh how much time they have and how industrious they are against what the plant needs and make personal adjustments. My job isn't to criticize someones personal decisions; rather, it's more nearly to point out the impact those decisions have on the plant.

I might explain in detail how to make a superior soil, and you might choose an entirely different course, which is fine by me - but I always feel obligated to speak up when there is something better for the plant .... to clear up confusion by pointing to the fact that 'good for the grower' is more often than not contra-positive for the plant; that is unless the the grower's only want is to provide what's best to the plant. That last phrase is offered for no reason other than to close a logical loophole.

When we look at things from the grower's perspective, there are no right or wrong ways, not even better or worse ways, because no one has walked a mile in the other person's shoes. When we look at things from the perspective of the plant, there ARE rights and wrongs as well as good, better, and sometimes best ways. We can't figure out what's right without contrasting it against what's wrong (from the plant's POV) and we can't figure out the comparative degrees of good/better/best unless we compare them against each other.

It's interesting that you provided a link to the Exotic Rainforest site. You might be interested to learn that the late Steve Lucas and I often had exchanges in these pages and we were always on exactly the same page when it came to soils. If you like, I'll look up some of the quotes that illustrate how consonant our views were.

Al

Thanks for the reply, Al! I've read many of your posts. My comment wasn't meant to be a criticism of your methods (I have none to give) but more to add to the discussion.

In the past I was frustrated when coming to these threads and not seeing any answers about specifics (brands, alternative methods, etc.). It's difficult for a newbie with unideal conditions! Prevention is great but if you're already in trouble, you should know how to fight! (Or run, whatever.)

Now that I've experimented a bit, I wanted to offer my plan of action so that hopefully others like me can find them useful. (Granted, I still know so little.)

I'm currently sprinkling Bonide Systemic everywhere... Got new plants recently and I think they've brought in a new family of flies. Sigh. The war continues.

Hey Al, do you have photos of your plants/gardens anywhere? As said, I've read so many of your posts, but would be awesome to see what you're growing!

Many pictures on this thread.

I'll post some here later if I remember or the thread stays active to remind me.

Al

Oops sorry. I was thinking this was your thread. It wouldn't be appropriate for me to post a bunch of garden pics on someone else's gnat discussion ...... but the link should give you a good feel for what sort of results I consistently achieve.

Sorry for the temporary derailment, Nephifofum.

Al

Water soil with camomile tea. It keeps fungus gnats off.

Can someone please explain exactly what type of mix of soil I would make for ideal conditions for my plants? I recently got two indoor plants from my local florist who brought them home from her nursery and one of them for sure came with what look like little gnats. I know very little about indoor plants and I'm learning as I go but I have no idea how to go about making my own soil mix! I would appreciate any help. Also I live in a small town that doesn't have many resources so if you can maybe let me know where a good place to purchase these things online would be I would really appreciate it!! Thank you!

http://forums2.gardenweb.com/discussions/2842847/container-soils-water-movement-and-retention?n=8

Al

In my firm, we use nematode predators on planting and our interior compost comes with MET52 in, a fungal disease which attacks the flies. Sciarid is our most annoying pest; as we used sealed pots and water fortnightly, our compost is probably wetter than many on here would counsel.

Just a random fact - I was taught this at a conference - the flies do not come in new compost as is widely believed, but are attracted to it. You can test this by putting some new compost under a cover. They are in the environment and are attracted to new compost, which like sharks and blood they can smell from some distance.

I've noticed a definite correlation between warm, damp weather and outbreaks of Sciarid. In the UK we had a really wet summer three years ago and they were everywhere!

Not a pro here, but if this helps, here's my fruit fly experience;

I took up vermiculture (worm composting), following online instructions. The instructions indicated to have them live in newspaper shreddings, I don't know if that worked for anyone else, but for us it began a fruit fly issue that did spread into some of our houseplants. For one thing we hadn't sterilized the worm castings before using them, that was a definite thing that allowed the fruit flies to spread to the plants. Google search some safe ways of sterilizing compost and soil that you think might have parasite eggs in it.

But to get the fruit flies out of my worm castings, I changed the system. I brought in a bucket of sand and a bucket of old dried out clay/dirt from outside, and every time I added a bucket of plant waste to the mix, I'd bury it in the surroundings, then put a fine layer of dirt and then a finer layer of sand on top of all of the mix.
That made it apparently entirely uninhabitable for the fruit flies. My theory is that to lay and incubate eggs, they need specifically the surface to be moist and rotten, I don't think they do a lot of burrowing, I'm guessing their wings would get damaged. So regardless of how organic the compost underneath is, they couldn't use it as a breeding ground so long as there was a barrier of dry sand and old clay-heavy soil.
After figuring that out, I always pot my plants with a drier, older, nutrient parched soil for the top couple of centimeters. Haven't had the fruit fly issue since.

Sorry if that wasn't concise! I thought it might help.

When I get fugnus gnats, I used to use the yellow sticky sheets- but they're inconvenient and I inevitably wind up yanking out a piece or two of hair dealing with them. But the bowl of water trick never did anything for me.

So these days, I take a white bowl, fill it with water, add a drop of dish soap and a drop of yellow food coloring. Works like a charm. The yellow attracts the gnats and the soap does something to the surface tension of the water such that they can't fly away.

Any time I bring home a new plant, I put together a mug or similar of this mix just to catch any gnats that might pop out before I change the soil.

*sigh* I rarely get fungus gnats anymore. :-( My carnivorous plants tend to eat them all. :-)

How can they eat them if you don't have them? ;-)

Al

ThT is indeed the dilemma, Al. Suppose I could pot up some peat and keep it wet in somewhere away from my cps in hopes that the occasional strays I do see might set up residence therein.... heh

Amazes me how effectively my cps eradicate fungus gnats.

So what do I do if i have gnats coming out of a gritty mix?

I have various plants in granigrit, turface, coarse perlite and a pinch of potting soil under a grow light. Medium dries within a day and a half, yet I still have gnats flying out of it... dry grit! I'm stumped, haha. I also have seedlings that need to stay moist, what do I do about those?

Forgive me if you already mentioned it, I've been skimming the other comments as there are so many

Thanks in advance

Do you have plants in soils other than gritty mix near those that ARE in gritty mix? If you have plants infested with gnats nearby, it wouldn't be unusual for them to explore the gritty mix looking for suitable accommodations, only to move on when they don't find rotting vegetation (which the potting soil you added does supply) to satisfy their hungry tummies.

Al