Arrrgh! Fungus gnats

Okay, I had read somewhere on this site that you could kill 'em with hydrogen peroxide in the water when you watered them. I put about 2 tbs in a quart of water and used that, but it has had little to no effect ... more peroxide? Different trick? Help, please?

Hey, I just did a search and found this ... get em' drunk! http://davesgarden.com/community/forums/p.php?pid=5521091

PC, are you using a fan in the room to get the air moving?

I'd also watch your watering--I never have trouble with the fungus gnats unless I've been watering a bit too much. You can use yellow sticky traps to get the adults and you can use mosquito dunks or Gnatrol to kill the larvae.

Some one had aquarium rock around some of her plants that she said helped with the gnats too.. They can't get down in the soil if you can get rid of them before hand.

If you don't have tons of pots, a layer of sand on top of the growing medium seems to help (Great Fungus Gnat Invasion of 1998 survivor) The sand will dry out quickly and the gnats don't have any dampness to procreate in. Sticky traps will eventually catch the adults, but it is terribly annoying to find them everywhere... (on the TV, on the counter, in the bathroom...not fun..)

They love moist soil and lay their eggs there. I use 1 tablespoon of liquid dish deregent in one half gallon of water and water the plant. They don't like that and it hasn't hurt my plants in the past and has always worked for me.

Hey ya'll, thanks for all the suggestions! This is my first year growing new plants (starting seeds and propagating plants, both) inside and yeah, I probably (heh, yeah, I did) overwatered - I haven't quite worked out the seedling needs yet. It didn't really bother me until someone mentioned that it can harm the plants after a while.

In the past if I have had some in a houseplant I could usually cope by taking it outside for a day or two - they don't seem like to like the great outdoors, but now I have a 4-tier rack with a lot of coleus and a few others very young starts, so adding something to the water sounds like a good way to go... the sand or gravel would be great on houseplants, but not this many, I think.

Wow, Melody - sounds like it *was* an invasion. Luckily mine are confined to a small area in the basement.

Wrightie, I do have a fan going, but due to the height of the racks it doesn't get to everything all the time...

Thanks all, for the suggestions. I think I'll start with letting things dry out a little bit, then do the dishwasher soap with the wine (little for them, little for me, little more for me... 8* ) )....and work my way up to the bT from there.

Happy New Year!

PC sounds like if you got enough of the wine in you, you could handle them LOL

Snort - *then* I just wouldn't care!

Yeah i don't think I would care either LOL

Pagen, if you are using soil to start your seedlings in, or even to plant in, that will keep the gnats going. soiless mix is the way to go in the house. I think the soil, being organic, is like having fruit on your kitchen counter.

Just my 2 cents.

Jeanette

1/2 cup (4 oz) H2O2 to 1 gallon H2O- and use it every time you water.

Cut back on watering like ecrane mentioned and a small layer of sand or gravel like Melody said will usually fix most fungus gnats problem. A few gnats won't harm anything but a swarm means things are out of balance (too much food and breeding places for them).

As I sadly discovered in my first big seed starting extravaganza in 1998. Got everything way too wet and had a terrible time getting it all in balance. I'd done small projects before, but had about 10 flats. Was overwhelmed by the invasion.

I'm OCD about keeping things on the dry side now, and everything gets watered from the bottom...not one drop from above, until they go outside.

Ha- I don't think I'm OCD about anything, but this could be a place to start! I got out of wack about the gnats before it became a swarm, luckily...

Thanks nedweenie - that tells me that my 2tbsp per1 or 2 quarts was waaaayyyy on the low side.

Hi Jeanette - I start in a soiless mix, but have been moving up in size with soil... the only protection I've had is that I've been putting the soil in the microwave (after putting it in a bag!) for about 10 minutes. It definitely kills all the seeds in the soil (and it pops all those little fertilizers beads that were in there, too) so I'm hoping it would damage and larva as well.

Thanks, everyone - I appreciate your wisdom and help!

Here's my 2 cents on what works for me. Hot water. Not boiling, hot enough to be uncomfortable, hotter than you would give a baby. I try not to pour any on the leaves or stems and an inch or so away from the stem coming out of the soil. I will sometimes stir the soil with a pencil before adding the hot water. This has always worked for me.

No kidding - has it ever hurt one of your plants, like maybe a bit too close to the stem? I've heard of people plunging hostas in hot water to get rid of the hosta virus, but this is a new one.

I am trying something new a good grower told me about. First of all the gnats are coming from a hoya supplier who is using Miracle Grow or something besides soil less mix. My friend said to get the Hartz pet shampoo........mix 1 tablespoon to a gallon of water and spray spray spray......even letting it get down in the soil........works everytime she said. (will even kill mealies if you don't know you might have them)

**edited to say I forgot that it is flea shampoo for pets

This message was edited Jan 2, 2009 10:44 PM

My 2 cents.

First I, starting last year have decided to bake my starter soil. I had an issue with the starter soil being bad from the start. Baked the soil for my second round of germination and that seems to have done wonders. I simply put it in the oven in a roasting pan at 250 for 15 minutes. Some people use a microwave to do the same.

Thought two is you can use straight up H2O2 with no water added. The drug store kind is already diluted with water. It's cheap and you can pour is directly into any pot and nothing bad will happen. It actually adds oxygen. I think I remember one guy who said that's what he waters seedlings with and uses no straight water.

I have also noticed Vermiculite used as a top dressing is very useful. It seems to hold water in yet will not grow fungus or let fungus get into your soil. If anyone has a comment on that I would like to hear. I'm not 100% on that one. LOL.

Forgot something. Soap is fine for plants but deadly for bugs. Nothing special, just dish soap will work. If you want to ramp it up a little tabacco tea will kill just about any insect too.

Interesting... now, vermiculite on top I could do - it's a little cheaper than gravel. But you said fungus, not gnats - ? It probably wouldn't do the same for them, eh?

I bought my Hartz flea shampoo today from Walmart...........amazing product for sure. It has pyrethins and two other ingredients.

The Gnats and fungus have something to do with each. No sure exactly what's going on but where there Gnats there is usually a fungus problem. Comes down to what I've tried and what has worked for me. Over watering plays a part in all this too. Not going to get my PHD any time soon. LOL.

LOL - you're doing better than I am!

Ok gessiegale, you use flea soap for the gnats and fungus?

Yes, and it works...........let me go back and see exactly what the measurements are to a gallon of water. My friend said to let the plants get almost dry and then spray like crazy letting some of it go down into the soil.............be back when I find the amount to use. I am thinking it is 1 tablespoon per gallon of water. If I don't come back, then you know that is right.......

Two questions:

1. I apologize (with much sheepiness) for my ignorance, but I never took Chemistry. What is H2O2?

2. I had read that coir is better to use than peat-based mixes to deter fungus gnats from laying eggs. Does anyone know if that's true?

Last year I started a bunch of seeds in Jiffy pellets. which are made of peat (my daughter loves to watch them expand). There appeared little white spots on the surface, which I was afraid were gnat eggs. I scraped off the surface of the peat--white spots and all--and the plants survived. Of course, it might not have been gnat eggs after all.

I thought I had read somewhere that gnats LOVE PEAT and but not so much coir. So for this year ordered a bag of Garden Solutions (TM) First Start Seed Starting Mix, which consists of "coir, perlite, worm castings and mealworm guano."

What are your thoughts? Thanks.

(Edited to add: I just noticed that this thread is in the "propogation" forum, and my question targeted seed STARTING. But the peat vs. coir question still applies, I think?)

Denise

This message was edited Jan 9, 2009 12:11 AM

H2O2 is peroxide household type The rest I can't answer, and you will probably get a lot of different opinions from everyone, on the coir versus peat. My self I think it is more what you chose to use. I have heard pros and cons on both.

Thanks, flowerfantasy.

I don't want anyone to think I am trying to hijack this thread by discussing the overall benefits of coir vs. peat. I am asking specifically if coir is less likely to beckon to the gnats..."Lay your eggs here, lay your eggs here..."

I have bad luck with peat pellets but some people do well with them. I tend to be an over waterer. LOL. Peats not for me.

No I don't think they will think that. There is a lot of nice people on here and I am sure someone will come along and give you a more exact answer to your question. There is another thread you might pose your question on also. Someone there might help too.

I'm not sure if coir is slightly more forgiving than peat or not in that regard but I think if you keep things a little bit (or a lot) too wet you'll have a tendency to get fungus gnats no matter what medium you use.

... although.... I was told that the eggs for the larva are already in the peat.

NisiNJ, don't worry about hijacking this thread - it's not one of my sensitivities, especially as I already got some great answers. The only problem you might have is exposure to your question - usually starting a new thread with a header about your question will get more eyes on it....

.... however, I have posted about your question specifically, as I bought a 6 pk of coir bricks, and didn't get a whole lot of response, I think it's still a fairly new product and few people have tried it, but keep on using the tried-and-true peat. Plus,. most pre-mixed products of potting soil, etc.., incorporate peat into their mixes. I would not add coir to a mix that already had peat in it, just because they both hold water, and could cause some problems with root rot.

There's two advantages that coir has over peat that I know of. Peat is not the easiest thing to re-wet once it dries, it takes some patience to get to back to a state where it's absorbing easily (although I've heard adding soap to your water helps). Secondly, the consumption of peat has grown to the point where the peat bogs are being depleted quicker than they re-grow. Even if the ecological impact is not something that bothers you, the chance that it will become protected or simply run out makes me want to find an alternative.

If there *are* gnat eggs in the peat when you buy it, that would be another big reason, as well.

HTH!

Proper watering is an art form, and one I haven't mastered! In the GH, plants can go from "adequate" to "dried out" in a matter of hours depending on ambient conditions. Only thing I've found that works is constantly prowling the GH, which is rather labor intensive. But H2O2 definately helps.

Thanks for your diplomacy and your answers. DG people are so nice. And informed.

I have found that watering from the bottom on inside plants under gro lights makes a big difference. Also, I just use that Hartz flea shampoo in the form of 1 tablespoon to a gallon and spray once a week. It keeps the gnats away.

I couldn't grow without peat moss and perlite.

I'm curious - many people have mentioned bottom watering - but that still only works if you don't put in enough water that the top doesn't end up moist, too, right?

I'm with you, Stono - - it's as bad as water color painting. I either overdo or under-do.

You can over do bottom watering. As stono said watering can be tricky to get it just right. I have to say starting seeds especially if you have a bunch is time consuming. One thing I do and I think others do as well is don't use all your seeds in one batch. I get one batch going and then the next of the same seeds. That way if there is a problem the first time around you don't ruin all your seeds. Veggies are different because they're time senstive so I don't think you would really want to break those up into different batches. Not sure I really don't grow much edible wise.

Nope Core, you're dead on! At least in my experience. I have found that the "batching" thing works, especially with the edible crops. With our squirrely weather here, I plant a "best guess" main crop at the appropriate time, then back it up with 2 week seedings "before and aft". One of those plantings has always emerged superior, but no (yet discernable )pattern as to which one. Don't think there's any way to predict the weather in any particular year, but we can optimize the probability of survival/harvestability by sequential planting...