I don't use any antibacterial soaps on plants because they are phytotoxic (poison to plants). I use either Murphy's Oil soap or Safer's Insecticidal Soap. ;o)

I have safely used a 50/50 mix of 70% isopropyl (rubbing) alcohol and water on everything I over-winter indoors. I've used 100% alcohol on many plants, but it's probably overkill, so I'd stick with the 50/50 mix. If you're worried - try it out on a few leaves before you go all out, but as I mentioned, I've yet to encounter a plant that reacts poorly to it.

Al

I don't want to interfere with your post but was wondering what you and Tapla were overwintering because I try to do that also. Am so glad to know about the rubbing alcohol. I did not know about that. Does that work outside or only on the inside? Thank you so much for your comments - Barb

It works inside or outside. I over-winter mostly tropical & subtropical bonsai trees under lights + a fair number of succulents & a few other uncommon houseplants along side of the trees.

Al

Hi Barb, I'm actually not using this for over-wintering, my sis has some plants that have a fungus knat problem, I am trying to figure out what will help them.

Al, do you use the above mentioned as a spray, water it in, spary leaves or just the foliage? I ask this cuz these knats are on the soil surface, not on the leaves, and I was told they attack the roots if left untreated. I would thinnk watering in (something) would be the way to go. Thanks, maid

Fungus gnats are a whole nother problem, alcohol will not kill them, you need to fix the soil. Remove any and all peat from the soil. Fungus gnats are the product of over watering and decomposing of the soil. Their larvae will not be affected by the alcohol and that is what you need to kill.

Ahhhh - you didn't SAY fungus gnats ..... Lol - alcohol will kill them, but the problem is their mobility - getting them to hold still long enough to spray them ..... and then it does nothing for the generations of soil residents ready for ascension, so it's pretty ineffective. ;o)

The coming and going of f. gnats is usually directly related to how you bend your wrist. Truly so. When you feel the urge to bend your wrist so water comes out of the spout of your watering can, think twice. Check to see if the soil feels dry at the drain hole. If it does, then go ahead and water, but if it doesn't - wait until it does & your gnat issue will likely disappear. If it doesn't, you could try 'Gnatrol'.

Al

I use one quarter of a "Mosquito dunk" in my watering can. It contains BT which kills the larvae in the soil. I use sticky traps for the adults. I also have Sundews (carnivorous plants) to catch them.

I think the point we need to take from this thread is "YES", there are things remedial that will rid you of fungus gnats, but unless you're growing bog plants, in almost all cases you can discourage them by adopting an appropriate watering regimen, and w/o adopting any other measure(s).

Al