Gnats, the umpteenth question.

10 years ago

I have an issue with gnats. Pretty common, I know, but I need advice because I really donÃÂ´t know why they just donÃÂ´t go away. I think they came because of my Peace Lily, from the store. At least I started noticing them after I got that plant (along with ants, thank you, but thatÃÂ´s another kind of nightmare). I repotted the plant, and sure enough, I think I overwatered it, because I had a huge amount of gnats a few days after. Since I donÃÂ´t have a fan in the room where I have my plants, I took them all outside and they have been out for three weeks or so. ItÃÂ´s been quite breezy, and I only water the plant when I notice it drooping, so I think (and this is where I may be wrong) that the soil gets pretty dry if the plant starts to droop. Still, all the plants that are outside seem to have gnats around them. What am I doing wrong? IsnÃÂ´t the soil dry enough if the poor plant starts to droop? How can I improve the soil? I was thinking of changing the soil and adding perlite for better drainage/areation. Anybody can recommend a ratio that would work?
I appreciate all advice and ideas!

Comments (4)

tommyr_gw Zone 6
10 years ago
The problem is that peace lily likes the soil to be always moist.

Go to the garden center and buy a pack of "Mosquito Dunks". Put one quarter of one in your watering can. This will kill the larvae in the soil. It is BT, which is a NATURAL larvae killer. For the adults use sticky traps.
rhizo_1 (North AL) zone 7
10 years ago
It is perfectly possible to grow peace lilies without being plagued by fungus gnats. The key is in providing a coarse, fast draining medium. Amendments such as perlite and conifer bark fines work well achieve that goal. If perlite is your only option, I'd mix it in at least a 50:50 ratio.

The addition of the perite will allow you to water freely as needed without providing an environment for the fungus gnats. I second the recommendation about the Bt, which will help bring the larvae under control.
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PhytoRo
Original Author
10 years ago
thank you both!! great advice!
faerybutterflye
10 years ago
I had a problem with gnats, also, for a little while. My mom told me to sprinkle diatomaceous earth over the entire exposed soil & it got rid of them. I think you can buy DE at any garden center or online & it's non-toxic.

P.S. What rhizo says will certainly work, also. The following year, when I repotted my houseplants, I used a much faster-draining medium with perlite & orchid bark mixed with some potting soil & haven't had any problems wtih gnats since switching.