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rosemctier

gnats in containers?

rosemctier
13 years ago

after a battle with gnats in some of my seedings inside, i am not worried about gnats in the containers outside. everything was planted in the same mix. has anyone ever had gnat problems?

Comments (11)

  • morz8 - Washington Coast
    13 years ago

    I have here where it's so wet all the time and mild, but I'd be surprised if you had the same issue there - at least not before later when the soil in your pots warms up.

    After one bad experience with them (brought them home in a new prayer plant and they invaded every pot in my home) I keep BTi on hand. Form I have now is Gnatrol and it's quite safe indoors, but where I'll find I'll need it is outside in containers at some point before growing season is over.

  • rosemctier
    Original Author
    13 years ago

    i live in the woods next to a creek-- it's always kind of damp, even in the sunny spots. i am happy to know that the BTi works. i've been watering indoors with it and made some home made gnat traps with tanglefoot. i'm thinking about making gnat traps for the containers outside. i will water with the bti when i need to water, but they are maintaining their moisture so far pretty well. i just hope i notice gnats before they cause too much damage.

  • gardenunusual
    13 years ago

    I just won a battle with fungus gnats indoors. I transplanted every single plant I had with fresh soil, washed every pot in a soap and light bleach solution. I found I had more than I thought.

    Then, I sprinkled diatomaceous earth lightly around the plants, not touching them. I had a few stray ones flying around after the transition, I got them with my hands. Haven't seen one since. Cross my fingers!

    Another method is putting a piece of sliced potato in the soil and yellow tape on the edge of the pot. The potato attracts the larvae, the tape attracts the adults.

  • carmen_grower_2007
    13 years ago

    Diatomaceous Earth works great and so does cinnamon. Just sprinkle it over the tops of the soil.

  • morz8 - Washington Coast
    13 years ago

    The problem I see with treating the top of the soil zone - it may work to prevent or for a lighter infestation, but once a good supply of eggs has been layed an ecco friendly soil drench (BTi) will do the best job for me. I've watched the adult gnats fly down and go in and out of drainage holes in the container bottoms, they don't seem that particular about where they can find moist soil and don't mind taking the wrong way in :)

  • SusanC
    13 years ago

    In the past, I have had fungus gnats cause considerable damage. -Here, right on the San Francisco Bay, we have the consistently mild, damp conditions that are just up their alley. After losing a bunch of seedlings, I pretty much had to declare war.

    I now sterilize my potting soil in the microwave before sowing. -This is because I actually found a wiggly little larval fungus gnat in a bag of potting soil, so I believe that is how I got such a bad infestation in the first place. I also buy mosquito dunks, which are cheaper than Gnatrol but have the same effective ingredients. If I notice fungus gnats flying around, I soak a mosquito dunk in some water and give all the seedlings a little drink to prevent any eggs from hatching. Since I started doing these two things, I haven't had any fungus gnat casualties.

  • rosemctier
    Original Author
    13 years ago

    i never thought of mosquito dunks or potatoes! trying them both. i am watering with the bti stuff but have not seen a difference yet. my tanglewood gnat traps are catching a lot of them though! plus, i feel like the karate kid or the chosen one or something-- i am getting quite adept at snatching them midair LOL
    thanks everyone!

  • morz8 - Washington Coast
    13 years ago

    rose, it takes about three weeks (consecutive) of adding the BTi water when watering before the breeding cycle is broken and larvae from any eggs laid are gone. Keep it up even if the adults seem gone in just a week or so, they only live a few days in any circumstance and they are not your target - target is the larvae so no more reach adulthood.

  • mnwsgal
    13 years ago

    I agree that the potting mix can be infected before you buy it. I had no gnats until I bought a new bag of mix and potted up some plants. These plants need to be kept somewhat dry and still there were gnats in just those pots.

    Fortunately they were kept isolated from other pots and using the m. dunks has worked to get the gnats under control.

  • rosemctier
    Original Author
    13 years ago

    thanks guys for your input! a few follow up questions:

    does anyone know how long the bti will stay in the soil? if i want to do preventative treatments,because i know those containers were exposed to the gnats and packed with the same potting mix, when should i start watering and how often should i do it? we get so much rain in the spring i wasn't expecting to have to water at all but i don't want my seedlings to be eaten before i even know there's a problem.

    i have found the mosquito stuff online in a pellet form. was thinking about scattering the pellets on top of soil so it would get worked in when it rains like slow release fertilizer or something. i am also wondering about the donut form of the dunks-- those of use who water with it, what proportion donut to water do you use? i am finding the directions on the pack rather frustrating as they give square feet water measurements and not cubic so i cannot figure out how to figure out volume. ugh. i called customer service and they had no idea.

    as always, thank you all for your help!
    rose

  • morz8 - Washington Coast
    13 years ago

    Rose, you can't make the solution too strong and you don't have to worry about how much BTi you get in there, just get some in. Rather than have bits of broken up dunk floating around to clog my watering can, when I used the dunk I just floated one whole in a bucket overnight, then used the water to water containers. Intermittent wetting and drying of the dunk isn't supposed to harm it so it can be put away to use again.

    The label on the liquid and granular water soluble products have the mixing in a wide range, it's something like a tablespoon per gal for light infestations all the way up to 8 Tablespoons.

    I think you'd need to use the pellets just as you would use a dunk, drop some in water and let it stand overnight before using the water. They aren't the same as granules that dissolve, they are time release in water. "To use at home, you simply drop these pellets into water, and they will float and slowly release BTI."

    The larvae have to be old enough to ingest the bacteria - I've never tried to use it preventively but at the first sign of an adult.

    If you can get your hands (online) on one of the Gardens Alive Coupons, they carry Knock Out Gnats granules and some times the coupon will just about cover an order.

    I've been buying 60 grams granular Gnatrol - that will easily last a couple of years which is the shelf life of the product anyway. $18.95

    Here is a link that might be useful: Gnatrol here

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