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Sterilising compost.
Brickman0430
Posts: 182
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.
0
Posts
Fungus gnats, brickman. Sometimes they damage root systems, have a look at the link below.
https://www.rhs.org.uk/advice/profile?PID=804
Many thanks for your help.
You can sterilize small quantities of compost by heating it in a microwave.
...if you don't mind the smell.
Tricky after you've sown in it though
and the OH doesn't catch you doing it..
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 nozzle
I caught a load on houseplants back in the autumn like that. Great fun!
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.