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Sterilising compost.

Brickman0430Brickman0430 Posts: 182
in Problem solving
Hi all, due to impatience I have started a few canna seeds in an electric propagator, however, after about a week or so, I've noticed quite a few little black flies appearing from the compost. Is there a way of sterilising compost before use? Or any other ways to get rid of the little lighters? Thank you in advance of any help, Pat.
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Posts

  • Dave MorganDave Morgan Posts: 3,123

    Fungus gnats, brickman. Sometimes they damage root systems, have a look at the link below.

    https://www.rhs.org.uk/advice/profile?PID=804

  • Brickman0430Brickman0430 Posts: 182
    Thanks for that Dave. Yes, looking at the rhs link, that's the little buggers. Which leads me to another conundrum, I can't let the compost dry out as I need to keep it slightly moist for the seeds to germinate, and chemical control (which I'm loathe to use) seems to offer only temporary relief. So, I need to find either a supplier of "clean" compost, or find a way to sterilise the stuff I'm using at he moment, which I should say is multi purpose compost.

    Many thanks for your help.
  • BobTheGardenerBobTheGardener Posts: 11,384

    You can sterilize small quantities of compost by heating it in a microwave.

    A trowel in the hand is worth a thousand lost under a bush.
  • Steve 309Steve 309 Posts: 2,753

    ...if you don't mind the smell.

    Tricky after you've sown in it thoughimage

  • BobTheGardenerBobTheGardener Posts: 11,384

    and the OH doesn't catch you doing it..image

    A trowel in the hand is worth a thousand lost under a bush.
  • Brickman0430Brickman0430 Posts: 182
    Yes, I did think about putting some in the microwave, I could wait until she's out shopping ???? But the compost was from one of the big diy stores, and the quality of it is shocking to say the least, and I actually did think there could be tiny bits of metal in it, along with the plastic etc. Many thanks for the replies, thinking about it, I'm giving these flies/gnats the perfect conditions for breeding, so unless I can think of a way of getting rid of them, my propagating days might be at an end.
  • ButtercupdaysButtercupdays Posts: 4,546

    I find the hoover very useful for dealing with fruit flies in summer, daresay it would work for fungus gnats too! Don't get too close to your seeds obviously, but if you stir up the flies a bit, you can suck them up as they fly, using the small nozzleimage

  • Steve 309Steve 309 Posts: 2,753

    I caught a load on houseplants back in the autumn like that.  Great fun!

  • SparklesJDSparklesJD Posts: 344

    I hoovered loads off my canna lillies - with only a couple of mangled leaves. They came in when I used multi-purpose compost to divide and repot (like you, I was surprised what seemed to be in it!).

    I think the earth discs are sterile (you soak them overnight), but even if not, the gnats won't be able to survive the dryness. I think houseplant / seed compost is OK, I'm new to it, but haven't noticed any problems since switching.

     

  • Brickman0430Brickman0430 Posts: 182
    SparklesJD, I don't know if you know it, but you are a genius, I had completely forgotten about earth discs, I've ordered 200 from Amazon, many thanks for that, domestic harmony is restored.
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