Hey everyone.  I've got gnats.  Every time I go in and do something (e.g. pot up a plant), I have 1 or 2 that try to escape.  I've had a half dozen sticky pads in and around my grow operation for about 2.5-3 weeks, and they've caught maybe 100-150 gnats total in that time frame, which really isn't that many.  They're not really getting much worse, but they're not getting better either.

At what point do you say screw it, and start insecticide treatment?  I don't *think* they've retarded any growth, but that's kind of a hard thing to quantify.  I know a female can lay like...300+ eggs per week, so that's obviously bad, but I've had them for well over a month, and they've not really gotten much worse...maybe 50% worse?  But I've also potted up a bunch of cuttings, so I'm probably introducing more larvae (via my media).

Thoughts?

Something that was popular in discussion at this time last year, is carnivorous plants.  Drop a Sundew or two in with the figs and watch them feast. I all found the when I had gnats, they came from my putting mix.  After leaving the mix out in sub zero temps for a few days.... no longer an issue.   If any do escape the freeze... the Sundews are happy to eat them. 

I ordered mine from WellSpring gardens along with a couple addition TC figs.

You might be able to find some at local nurseries, I was not so lucky. 

Scott

Interesting.  I noticed in a few of the search results that carnivorous plants were mentioned.  That's pretty awesome if they're that effective.  You'd think the gnats, being soil dwellers, wouldn't be interested in anything sweet or colorful.  We do have a couple local nurseries in town, and I'm always looking for excuses :-D

I found that laying the sticky traps flat caught more gnats than having them upright.  The carnivores plants are in soil, and produce a "scent" both will attract the gnats.  

Just match the plant to your growing conditions to make sure they thrive, unlike the figs, they do need a lot of water, many are bog plants. 

A lot of us have had success putting gnatrol into the water every time you water.  That plus, a couple carniverous plants plus occasionally using sand over the top and blocking drainage holes with nylon material (from old pantyhose) has worked for me.

Mosquito dunk(or bits) in your watering can should help.

I agree with all solutions mentioned. I have a large, heavily planted tortoise enclosure in my house and it's always a cyclical battle with gnats. I've used a combination of yellow sticky cards, Nepenthes (carnivorous plants) and good ol' fashioned window power with pretty good results. I've also used Gnatrol when watering houseplants. Unfortunately, when using most types of moist plant media, you'll always have gnats. The only thing you can really do is keep the population low and wait out the cycle.

However, if you find out the secret of keeping gnats away forever, I'll be your best friend :D

I been fighting gnats and now spider mites (neem oil wkly) for the last few weeks.  I noticed that the sticky fly strips from Home Depot have caught more gnats then the yellow sticky paper and it was cheaper by far.

I have also been using Gnatrol WDG, expensive but well worth it, when you consider all the money and time you have already invested in your cuttings.  The first 2 drenching have been at 3tsp per gallon (they suggest up to 4-8tsp for extreme), plan on doing that again before watering with 1 tsp per gallon.  If you like me had a medium to heavy infestation, you might consider buying the 1 lb gnatrol.  I bought the 5oz at first and it only did 10 gallons of the product. I also used dechlorinated warm water and only mixed up what I needed for the day.  Hope this helps.

Hello everyone. Brett, I'm in the same boat as you my friend. I was asking myself "how do gnats get in here so quick??? And when???!!!". I had one cutting that rooted well and was just beautiful, then all od a sudden it was producing gnats like that was it's job. I bought something from my local hydroponics place without chems, it worked well but left my cuttings drenched because it has to be applied with water. I decided to transplant a couple as a trial and as I went into my soil bag it was also full of gnats. WTF!? I thought, the bag was closed pretty good but they still got to it. That's when I realized I was using "infected soil", infected with gnats and their eggs, that's why I have gnats in my cuttings. So I made a batch of soil I had used on cuttings that rotted or died, put it in a plastic bag and zapped it in the microwave (when my wife wasn't looking) for about 3-4 mins, let it cool off and transplanted a few cuttings in the sterilized soil mix. I might get gnats again but it'll give the cuttings enough time to mature, hopefully. I did 6 cuttings in sterilized soil and put them together in a plastic bin and left 6 of the old cuttings that are rooted well but infected with dirty soil in another bin, it's only been a week but no sign of gnats in the new batch. Btw, my wife found out I used the microwave to heat up dirt and I've been banned from the house if I'm working in the yard now. Bought a microwave just for the garage and to sterilize my mixes in the future. Soooo, that's what I did and seems to be working well for me...

Some like it some don't but it worked 100% 

http://figs4funforum.websitetoolbox.com/post/gnats-and-cuttings-7154788?pid=1284950754#post1284950754

I don't keep my sundews by my fig cuttings at the moment, but man, they work well. All summer long you can barely see red hairs on the leaves because they're carpeted with gnats. I also have some venus fly traps and pitcher plants the kids and I like to feed - or rather, supplement. They catch plenty. The pitcher plant, by end of season, must have had dozens of yellow jackets dissolving in five separate pitchers.

Brett, all i can say is that sucks and the problem is probably worse than you realize.  Lost most of my cuttings to em last year and in some previous years.  Sadly I'm close to taking the title of Gnat Expert except for one key point... I don't have a solution.  Only lots of experience with the problem.  I've tried many things last year to no avail.  Check some of my old threads to see some of what I tried last year.  I was using Jon's Uline bag method and I think I completely removed all cuttings, sterilized medium in microwave and started over multiple times.  No luck.  Put a dent in em and felt good knowing i was nuking those freaking larvae, but ultimately proved useless.  One point of consideration however, if you sterilize your medium in microwave, make sure you don't do it too long or too short.  Too short and you don't kill em, too long and it causes soil to release toxins that are bad news.  I think the official time is something like 2:30 for a gallon ziplock with 1-2 lbs damp soil.  I would google it and double check the times.  I'm testing a number of new techniques this year.  Will make a new thread if I have luck with any of them, but short of having a solution, don't want to waste your time.  I will mention that the biological gnatrol products didn't get it done for me, likely bc the problem was too far gone when i started using those products, but i noticed I was getting strange mold in my containers where I had higher concentrations of the shaved dunks.  Good luck!
Timothy

Has anyone tried watering with a solution of 1 part peroxide to 4 parts water?  I've read this is effective but I cant say for sure.

Only thing I can say is make sure you don't overwater from now on.  A couple years back I had a gnat problem and I used water with those mosquito dunks.  But in order to try to kill the gnats I watered too much and that made the problem worse.

Cuttings can definitely survive a gnat infestation; many of mine did.  However, if you overwater at the same time, the success rate will be very low. 

I have no experience with carnivorous plants, but it's hard to imagine they eat enough gnats to control a major infestation.  How many gnats does each plant each each day?  Because those fly traps can get 100 in a day easily.  Seems easier and more effective (thought I admit carnivorous plants are much cooler and more interesting)

You can point a fan at the plants also, FGs are weak flyers. It will also help dry the mix out and toughen up the plants. 

I have experienced an early gnat problem this year. I have well over a hundred small starter trees in the house and its starting to get ugly. I will be watching this thread closely lol.

I've found Gnatrol works very well.
One problem is people think the mosquito dunks or bits will work just as well because it is supposed to be the same organism.
Well they don't , they may help but won't give you the complete control like Gnatrol can.
So if you've used dunks and they don't work , don't think that you've used Gnatrol , it is just not the same.
No real need for systemics , if you use Gnatrol at the medium to high rates.
I think I got mine from organicbti ( or something close to that) on ebay and the price really wasn't bad.
When I pre moisten the potting mix for cuttings the water I use contains Gnatrol .
Hope everyone has a great propagation season this Winter/Spring.

drivewayfarmer, I wasn't just using dunks if that's what you were thinking.  I mixed shredded dunks in with my mix when i bagged em, but also watered with bti.  Can't remember the name off the top of my head, but it was supposed to be the same as gnatrol.  Oh, I prewet the mix with it too.  Not trying to argue with what's worked for most, just saying it didn't work for me.  In all fairness though, I think my product wasn't gnatrol brand, like i said.
The best thing I've found so far is letting things dry out before watering again.  However, hard to do this with cuttings.  I prefer to avoid peat based mixes for rooting going forward, going coir instead.

Gnatrol (BTI) works well.  I use it at medium strength when I wet out my potting mix prior to up-potting (or cupping), and as needed when watering indoor plants (i.e. if I see even one gnat).  I had a gnat problem a couple months back and now have none.  I also use a fan which helps keep the gnats away and helps to strengthen the growing branches.

Gnats come with the organic potting medium.  As far as I know the only way to completely avoid them is to use a completely inorganic potting medium.  I believe RichinNJ uses 100% perlite and has no gnat issues.

If you see gnats, you have their larvae in your soil, feeding on your roots.  For new starts, this often results in death.  So to answer your question, now is the time to call it an emergency.

Hi Timothy ,
I wasn't replying to your thread specifically , just putting in a plug for Gnatrol because it has completely solved the problem for me and I had spent a lot of time waiting for the mosquito dunks and bits to work the same way , but they never fully did.
I hate to see any of us having to do extra work to control gnats in our cuttings when the Gnatrol works so well.
It is good if new folks know that dunks or bits won't work the same way as Gnatrol.
I wish they'd package the Gnatrol in smaller containers so it would be available on the Agway or local store shelf for anyone needing a small amount for houseplants etc...
, but I can only find it on ebay in a smaller package.
Like you , I'm trying coir for some rooting this season as well.

1.  Yellow Sticky Traps
2.  Gnatrol (Use with your regular watering/fertilizer schedule, not in addition to it)
3.  Neem Oil
4.  Carniverous Plants
5.  Nylon stockings or paint strainers over pots (the BEST!)
6.  Mosquito dunks in watering bucket (always) when it's under control
7.  Lots of swearing

I've been topping pots with limestone screenings, not a single gnat.

There are no gnats in coir, guaranteed, it is heated when compressing into a brick. Promix has always been good to me also.

I thought the dunks worked for me in the past? Must have been the reduced watering and sticky traps then. I have never had the full on infestation that some people describe. If I ever do I would never use the same potting mix inside again "an ounce of prevention is worth a pound of cure".

Kelby,

Do you have an explanation for this phenomenon? I have also heard / read that certain sands maybe a particular coarseness of sand will achieve the same effect. Thoughts?