Getting rid of gnats in houseplants with beneficial nematodes (awesome little critters that eat gnat larvae)

I recently wrote a definitive guide to getting rid of gnats. I thought I might provide you with an update. 

The tactics I tried (specifically, a combination of covering the pots with aluminum foil, dusting the soil with cinnamon, a homemade trap using white wine, and lots of yellow sticky traps worked like a charm. Well, mostly. Every now and then at night a gnat would still fly into my face as if to say "ha ha, you missed me!"

Given that one little fungus gnat can lay up to two to three hundred eggs in its lifetime, it stands to reason that I'll still miss some. And so it was time to bring in the heavy artillery. 

David at Gardener's Supply was nice enough to leave a comment on my post talking about something they sell called Gnat Guard, or "beneficial nematodes" (if Gardener's Supply Company is out of stock, you can buy the same thing from Amazon sellers called Scanmask). I had no idea what a nematode was, but since the word "tode" is in there, for some reason I thought of little frogs. And as annoying as a home overrun with gnats are, I figured it'd be a lot more annoying to be overrun with frogs. 

Well, of course had I not been asleep in biology class all those years ago, I would know that a nematode is a tiny roundworm. Now, roundworms get a bad rap out there because there are some nasty ones out there that get into people's tummies and into dogs' tummies and whatnot. 


But something I never knew was that there are good roundworms too. Specifically, little microscopic roundworms that, if put into soil, get in there and start munching away at insect larvae (including gnat larvae), but do zero harm to the plants or to you, your pets, and your kids. Beneficial nematodes have been used by farmers for years as an effective means of pest control without using chemicals or pesticides. 

(Having said that, my hats off to the marketing folks at Gardener's Supply Company for calling them "beneficial nematodes" and not "parasitic roundworms").

So, since I was still being overrun by these gnats, I wrote a little note to the good folks at Gardener's Supply Company asking if they could send a sample. I got a nice note back from their PR department saying that a sample was on the way, and giving these instructions:

** You may apply GNAT GUARD anytime soil temps are between 35-85 degrees F.
** Ships UPS (2nd Day) only- allow 1-3 weeks for arrival.
** OPEN IMMEDIATELY upon arrival. Product arrives in a mini-cooler with a
   cool pack inside to keep it from overheating. Product itself (sponge)
   is OK if warm, room temp, or cool to the touch. Store in refrigerator
   if you can't apply right away (be sure mini-cooler is open).

Lo and behold, yesterday I get this package in the mail: 

Now what I do remember from biology class is that insects have six legs, and roundworms have none. But I figured Gardener's Supply Company use the same yellow sticker when mailing out things like ladybugs. I opened the box, and thankfully nothing flew into my face.

This is the "cooler", using a miniature version of the ice packs some companies use when sending fresh fruit or perishable food. It was all very neatly packaged, I have never seen a cooler cooler (sorry). 

Inside the cooler was this small zip-lock bag with a sponge inside:

The instructions said this:

Gnat Guard

A biological control to rid houseplants and seedlings of fungus gnats and over 100 other insect pests. Gnat Guard nematodes target insect pupa and larvae living in moist soils in the root zone.

Active Ingredient: Steinernema spp.

Contents: 1 million covers 2,000 sq. ft.

Application: (see back label for release information.) For houseplants: 2 tablespoons of concentrate per 8-inch diameter plant. Apply 1 to 2 times per year. For greenhouse plants: apply 1 to 2 times every 3 months.

Storage: These nematodes are alive and should be released as soon as possible. Inside the package is a moist sponge which contains the nematodes. (You can see them with a magifying glass.) Refrigerate at 40 to 50 degrees F to temporarily store the nematodes for a maximum of 2 weeks. The sponge must remain damp. Add a few drops of water if the sponge appears to be drying out. 

Release: Remove the sponge from the package. Nematodes migrate into the sponge during shipping. Rinse the sponge and sponge package completely into one gallon of water. You now have a concentrate. Constant agitation of the solution while applying will ensure the most consistent coverage. For smaller applications; such as for houseplants and seedlings, you may use a watering can. For larger applications; such as for greenhouse plants, you can apply the nematodes using an injector system or dilute them with more water and use a pump sprayer, hose-end sprayer, watering can or pail. Do not leave the nematodes in standing water for more than 12 hours.

Important Note: The Gnat Guard must be "watered in" to the soil. A rinse of plain water after they have been applied will help ensure they have been carried into the soil. 

And so I following the instructions. I took the blue sponge out of the package. I wasn't tempted to take a magnifying glass to look at the little squirming critters as the package suggested. I figure they'd be happier if they didn't get a good look at me and vice-versa. 


I wasn't sure exactly what it meant by "rinse the sponge and sponge package", but I figured this would do it. I bend the sponge into the spout of a one-gallon cleaned-out milk container and put it under the sink's tap. 

Once the jug was almost full, I put the sponge in and gently shook it. Presumably, millions of little wormies were now swimming around in the water.


The next step was pouring it into my big plant pots. As you may recall, one of the tactics I used was to cover the top of the planter with foil like this. 

This was pretty effective as far as keeping the gnats away, but one unintended consequence was that when I took the cover off, there were at least 2-3 other kinds of creepy crawling things that decided they liked the dark, moist environment. I suppose they'd been sitting in the soil the whole time. Hopefully the little fellows can chomp up their progeny as well as the fungus gnat babies. 

Anyway, I poured the nematode concentrate into each pot I could, and then followed it up with more water. When I looked closely at the soil, it sort of "glistened", and I knew my little friends were at work. Now, I thought I might be a little grossed out by the thought of those little things in my house, but at the end of the day I've grown quite fond of them. They're like thousands of little friends who are helping clean my house. And they're safe to have around you, your kids, and your pets. 

It's been a few days now, and not one gnat has flown into my face. And so as thanks to Gardener's Supply Company I will happily endorse this product. 

Second Plant: yur fiahed!

With apologies to Donald Trump...

Remember way back when I told a story of two plants? The plant to the left was an eager overachiever from the start, while the one to the right took the longest time popping out.

Aerogrow was nice enough to send another pod, but as I got it in the mail, the second plant finally popped up.  While I never really expected much from it, I figured I'd let it ride and see what happened.

Well, if you take a look at the garden. it's a little misleading.

It looks like both plants are thriving. But upon closer examination, the bulk of the foliage is from the plant on the left. The plant on the right really never produced a thing. It grew big, and it's sucking up a lot of the water and the nutrients, but at the end it never produced any flowers. A few weeks ago, some buds did form, but within a few days they dried up and fell off.

So, as it says in the Good Book, "any tree that does not bear good fruit is cut down and thrown into the fire". I tried all I could to get this plant to produce, but at the end it never did. So, off with its head.

Interesting still, when I removed the pod from the Aerogarden, three gnats flew out. Yes, the same gnats that I spent the last post trying to get rid of. Seems that the gnats were flying their way to the bottom of the stalk and laying eggs in the seed pod the whole time! Yet another reason to get rid of the underachieving plant.

So, it's down to one plant, but as you can see it's filled up the unit quite nicely on its own.  Hopefully now that it will get all the light and all the nutrients it'll step up even more.

Getting rid of gnats in houseplants

Remember a few months ago I was having a problem with all kinds of critters like whiteflies in the warm weather? I thought I would have a reprieve in the winter, but it seems that I'm being overrun with gnats now.

Gnats (or going by their official name, "fungus gnats") are the same general size as fruit flies (which are tan) or whiteflies (which are, of course, white), but are black. They don't bite or even hurt the plant (except for really young plants and roots) or anything like that, but they're super-annoying because like mosquitoes, they like to buzz in your face and your houseguests' faces at the most inopportune times.

For the past week, I've been obsessing with getting rid of these critters, so I've searched high and low on the Internet for answers. I suppose solace is to be taken in the fact that if these things are bothering you, you're certainly not alone.

Here are some tips for getting rid of them.

• First and foremost, get them at the source. Gnats love to lay eggs in houseplants, especially houseplants that are overwatered and have decaying matter in the pots. Here are some basic things you can do short of throwing your houseplants out:
  
  
• Let your plants dry out completely between waterings. This will kill any eggs and larvae that managed to slip in. Your plant will wilt, but it'll survive, but the fly eggs and larvae won't.
  
  
• Clear out any dead foliage in your plants. Gnats love decaying plant material.
  
  
• Repot your plants with clean soil.
  
  
• Consider piling a bunch of sand on top of your soil.
  
  
• Consider using saran wrap or aluminum foil to cover up the top of your flower pot so the soil is not exposed and flies can't get in.
  
  
• Use cinnamon. That's right, cinnamon. Buy a huge jar at BJs or Costco, and dust a whole lot of the powder onto your houseplants' surface. Any flies on there will scram, because they hate the smell. And they'll never lay their eggs there.
  
  
• Get a handheld vacuum cleaner (I like the Dyson Handheld Vacuum). When you see one, suck it up. Not only do you get rid of one more gnat, you get the enjoy the satisfaction of seeing them buzz around in the canister instead of in your face like some kind of odd science fair experiment.
  
  
• Make your own trap. Just get a jar with a tight lid. Fill it with a substance that gnats can't resist, cover the lid, and poke holes in it. The gnats will fly into the jar but they won't be able to fly out, so in a bit of poetic justice, they'll end up drowning in the very concoction they so greedily tried to get. There are a million suggestions of what to add into the jar, I've heard people say the rind of a lemon, white wine, apple cider vinegar, an old piece of a banana peel or lemon.
  
  
• Invest in some Yellow Sticky Traps from Gardener's Supply Company. These worked like a charm with whiteflies before, and they seem to be working like a charm with the gnats. The critters are attracted to the bright, very sticky yellow paper and will fly right into them to their demise. As a bonus, they'll act as a "fly detector" too...put them around your Aerogarden and around your houseplants, and the one with the most flies stuck to it will provide a hint as to where the bugs are laying their eggs.
  
  
• Make sure there's no standing water or rotting food in the house.  If there are, gnats will find them before you do.
  
  
• If nothing else, you have a chance to practice your "Mr. Miagi". You don't have to use chopsticks, but it's definitely in your best interest to use your kung-fu skills to smack them with your hands as soon as you see them. An adult can lay 150-300 eggs at a time, so you need to eradicate them as soon as you see one. They are rather quick--there was one the other day that I couldn't get no matter how quickly I clapped my hands, so it ended up sounding like I was giving it a round of applause.
  
  
• Some people swear by hydrogen peroxide. You basically mix 1 parts H2O2 to 4 parts water, and then water your plants like normal. The mixture will supposedly destroy the gnat larvae in your plants as O2 is released (think of how peroxide reacts when you put it on a cut), but then after the reaction turn to good old fashioned H2O. For me, this didn't quite work, but if you happen to have peroxide around the house it's worth a shot.
  
• Now, where your Aerogarden is concerned, gnats love moisture, and they WILL find the hole in your seed pod. And there is nothing quite as revolting as seeing a bunch of little white larvae in your seed pods. Once your plant is mature, consider taking a little aluminum foil and covering up the hole, and constantly checking the leaves and the waters for critters.   

I'm not sure how all these gnats got into my house, but I'm trying all of the above to get rid of them. What seems to be working the best are the yellow traps, which I've taped to the sides of my Aerogarden. The next best thing, believe it or not, is the white wine. Each morning I see a few more flies in the jar who partied just a little too hard the previous night.

UPDATE: Since I wrote this a few years ago, I've had to deal with a couple more infestations. Here are two other tactics that work well, if none of the above work for you.

• Beneficial nematodes. These are microscopic parasitic worm-like organisms. Now before you start freaking out, I should say that these are good parasites. They're harmless to humans, pets, and plants, but deadly to fungus gnats. Specifically, once you release these little guys into your houseplant's soil, they'll home in on the fungus gnat larvae and (get ready to get disgusted), bore into their bodies and release a bacteria that kills the larvae within 48 hours. Then, like Luke Skywalker living in his Tauntaun, it'll use the shell of the body, feeding off of it and the bacteria. Long story short, after a while all your fungus gnat larvae is quite literally dead meat.
  
  Nematodes are easy to use; I've bought them from Gardener's Supply Company and from Amazon and have had good success with both in the past. In both cases, you're sent actual live nematodes in the mail (usually packed with an ice pack to keep them live during shipment). They'll be embedded in a spongy material (in the case of Gardener's Supply) or look like a white powder (from Amazon), which you mix into a gallon of water. If you look really, really carefully, you'll notice tiny little squirming things, who will be your new best friends. You water them into your plants and let them do their thing. 

• Nematodes worked for me wonderfully the first time I tried them, but for some reason the second time I tried them they failed--the number of gnats got less but there were enough survivors to spawn a new generation--and because nematodes are pricey I couldn't afford to spend more money. That's when I turned to Gnatrol. Unlike nematodes, Gnatrol is not a living organism, but rather a bacteria found naturally in soil. Instead of being eaten, gnat larvae eat this bacteria (Bacillus thuringiensis subspecies israelensis) and then the bacteria produces proteins that react with the larvae's gut lining, basically making them unable to eat. Sure, it sounds a little mean, but after weeks or months of breathing in random gnats, you'll be thankful for it. 

Hopefully one of these tips can help you finally get rid of fungus gnats. 

Harvesting the first Aerogarden VeggiePro Tomatoes!

In the Good Book, there's a verse that says "Four months more and then the harvest". Well, four months after planting the first seed pod, I have my first harvest of tomatoes!

They are real tomatoes, all right. Somewhere between the size of cherry tomatoes and full-grown tomatoes. They're plump, red, and smell great (or as great as tomatoes generally smell)

I racked my brains trying to think of an appropriate way to prepare my very first harvest of tomatoes. The first thing that came to my mind, of course, was insalata caprese, which I've made before. In fact, I even have some former Aerogarden basil which I transplanted. Which means the only ingredient for this dish I didn't grow myself was the cheese (and believe you me, once Aerogarden releases their grow-your-own-cheese garden, I'm going to be the first on line :P).

Step one was chopping up the tomatoes. Luckily, I had not grown too emotionally attached to the little guys that this was difficult.

Look how juicy it was.

As you can see, my knife wasn't sharp enough, so remembering the old ginsu commercials, I brought out the sharp knife (which can cut through this tomato as well as a metal can).

By this point I'm getting pretty psyched up. This is the first time since I was in high school that I harvested my very own tomatoes that I grew myself. And it's the first time in my life I harvested my very own tomatoes in January!

The next step was going to my truly old basil plant and picking off a couple good leaves

Now, our local supermarket had mozzarella cheese on sale, but it was the kind that was flat and you rolled it. This is what the package looked like:

Naturally, I wanted to make my insalata caprese just like they did. So I rolled out out the cheese, laid all my tomato slices and basil leaves on it.

After drizzling it with some of my cousin's olive oil and putting some salt and pepper on it, here's what I got.

Not quite the same thing as on the package, but at this point I didn't care. It was yummy yummy good.

Overall, I was very happy with the tomatoes. They looked like tomatoes, felt like tomatoes, smelled like tomatoes, were amazingly juicy, and tasted like really, really fresh tomatoes.

Looking at the plant, I see there are about four more large tomatoes and a couple flowers coming in. I'm still doing the two-week feeding, I'm still adding about 2 liters of water every few days, pollinating the plants, and  trimming the excess leaves from time to time. Let's see how long we can get this thing to last!