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north53zone2b

fungus gnat invasion

north53 Z2b MB
10 years ago

A few weeks back when I was bringing houseplants back in and rescuing other plants that I wanted to save I needed to purchase some potting mix. Seeing that I live in a small town, I had to get the only thing available which was Miracle Grow brand. I've read lots of negatives about it but bought it anyway. What a mistake!

I now have fungus gnats everywhere. Some plants are crawling with them. I've stuck the Safers yellow sticky flags everywhere.
I'm not sure what else I can do... Except to make sure next year that I have something decent on hand. I don't know how they can sell that garbage.

Comments (5)

  • tapla (mid-Michigan, USDA z5b-6a)
    10 years ago

    Use a wick to help drain the excess water; or, after watering, if your pots are small enough, hold your pot over the sink & move it up and down. You'll soon discover that as you reverse direction from down to up, the water keeps moving down. The faster you move the pot down and the sharper the reversal, the more excess water you're able to remove by putting the physical law of 'inertia of motion' to work for you.

    You could always change soils ..... or ck out the link I left that will offer other tips on how to live with excessively water retentive soils.

    Al

    Here is a link that might be useful: Try this for tips

  • Danielle Rose
    10 years ago

    You've got to kill the larvae. Use Mosquito Bits and/or Mosquito Dunks. I buy the Bits on Amazon; it's $10, and you can treat 20 or so plants for a couple of months with it. With the Bits, you shake a good amount over the top of the soil, and whenever you water, the bacteria will wash down into the soil ... kills the gnat larvae, not the plant. The dunks go in the watering container.

    What will also help immensely is to allow the plant to stay as dry as possible, even to the point of stressing the plants. Larvae can't live in dry soil. Most of my plants are succulents and can take a little drought, but I have a few that need moisture at all times or the leaves will start dying. I refresh the Bits on those plants once a week. Eventually, the gnats will be gone. It will take 2-3 weeks of vigilant treatment every time you water.

    Good luck. I HATE FUNGUS GNATS!

  • rhizo_1 (North AL) zone 7
    10 years ago

    Time to do some homework, north. Click on the link below to view some of the manh (hundreds) of old threads on this very subject, here in the GardenWeb.

    Here is a link that might be useful: Fungus gnat solutions

  • birdsnblooms
    10 years ago

    The Yellow Sticky Traps should help.
    Do you see gnats on the traps?
    Traps definately attract whitefly; never used them for gnats.

    For the time being, 'besides following advice from other members,' made sure soil dries between waterings.
    If it's not too cold to open a window, do so.
    A fan helps, too. Air from fan should not hit leaves directly, unless it's rotating.

    Good luck, Toni

  • north53 Z2b MB
    Original Author
    10 years ago

    I don't usually have a problem with the fungus gnats. I never overwater my plants. I'm sure the larvae was in the soil when I bought it. There's just too many of them for it to be anything else, IMO.
    Tapla, I would transplant the affected plants if I could buy any decent potting mix. There's none in this town. Even in the spring it was difficult to get anything good. I usually stock up when we go to the city, but we didn't get there this summer.
    Anyway, the yellow flags seem to be reducing the number for now. Plus the furnace is now running regularly so the lower humidity should help. Thanks all.